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- 1Genetic transformation and functional characterization of Chimonanthus praecox SAMT gene in tobacco
- 2Forest canopy height estimation using LiDAR and optical multi-angler data
- 3Quantitative analysis of stand spatial structure of Cunninghamia lanceolata non-commercial forest based on Voronoi diagram.
- 4ENVI-met model; sensitivity analysis; three-dimensional temperature field of vegetated scenes
- 5Forest carbon sequestration potential in China under the background of carbon emission peak and carbon neutralization
- 6Responses of leaf morphological traits for broadleaved woody plants along the altitudinal gradient of Changbai Mountain,northeastern China. Journal of Beijing Forestry University
- 7Changes in forest resource carbon storage in China between 1949 and 2018
- 8Bioinformatics analysis of expansin gene family in poplar genome.
- 9Transcriptome analysis of gene expression profiling in the suspension cells ofPopulus tomentosatreated by histone deacetylase inhibitor TSA
- 10Pathway and method of forest health assessment using remote sensing technology
- More+
- 1Effects of soilforming rocks and sprout ages on the bark quality of Pteroceltis tatarinowii
- 2Changes of configuration and major chemical components for eucalyptus wood pretreated by steam cracking
- 3Biomass and net primary productivity of three plantation communities in hilly land of lower subtropical China.
- 4Overexpression of Populus euphratica peuMIR156j gene enhancing salt tolerance in Arabidopsis thaliana
- 5Quantifying the soil carbon changes following the afforestation of former arableland
- 6Rapid light-response curves of PS chlorophyll fluorescence parameters in the leaves of Salix babylonica, Salix ‘J172 and Salix leucopithecia to Cd2+ stress
- 7Effects of stand density on community structure and species diversity ofCupressus funebrisplantation in Yunding Mountain, southwestern China
- 8Spatial continuity of fuels in major coniferous forests in Beijing mountainous area: fuel vertical continuity and crown fire occurrence.
- 9Life table and survival analysis of Osmanthus fragrans wild population
- 10Studies on the wood fiber-rock wool-composites
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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
Display Method:
Abstract:
ObjectiveCarbon (C) and nitrogen (N) elements are crucial for plant growth and development, especially in extremely arid inland river basins. Plants in different functional groups would show different stoichiometric characteristics due to the variations in requirements for soil water and nutrients. It is of great significance to explore stoichiometric characteristics among different plant functional groups in the lower reaches of the Heihe River of northern China, as well as their nutrient content responses to groundwater fluctuation, aiming to further understand desert ecosystems under the background of global climate change.
MethodIn the lower reaches of the Heihe River, a total of 22 sampling sites were set up according to the vertical distance between vegetation and river. Correlation analysis and variation partition analysis (VPA) were applied to determine the relationship between plant stoichiometry and environmental factors among plant functional groups, respectively.
ResultThe results showed that the average C content of leaves and fine roots of plants in the lower reaches of Heihe River were 408.53 and 16.30 mg/g, respectively, while the average N content was 500.34 and 11.81 mg/g. The average C∶N ratios were 30.74 and 49.48, respectively. Compared with global and regional studies, it was found that plants in the lower reaches of the Heihe River had higher C content, lower N content and higher C∶N. Different from herbaceous plants, the C content, N content and C∶N of woody plants were significantly correlated with the changes of groundwater depth. We found that the stoichiometric characteristics of plant carbon and nitrogen in the lower reaches of the Heihe River were significantly correlated with soil properties. The groundwater and soil variables jointly explained 53%?5% of the variation in woody plant stoichiometry. Additionally, soil pH and soil electrical conductivity explained 20% of the variation in herbaceous plant stoichiometry.
ConclusionOur study finds that groundwater is the key factor affecting the carbon and nitrogen stoichiometry of woody plants under extreme drought and saline-alkali environment, and the carbon and nitrogen stoichiometry of herbaceous plants is mainly influenced by soil pH and soil electrical conductivity.
,Available online,
doi:10.12171/j.1000-1522.20230054
Abstract:
ObjectiveThe true interfacial shear strength of the wood/phenolic resin (PF) bonding interphase was investigated via the fiber pull-out method in composite materials, and the fracture morphology of wood strips and the failure mode of cell wall layers after pulling out, were analyzed to provide theoretical support for revealing the fracture mechanism of wood bonding interphase.
MethodTwo types of earlywood and latewood strips/PF resin bonding specimens were prepared, respectively, according to the preliminary exploration of test conditions. The average interfacial shear strength was calculated by using the data collected from a universal mechanical testing machine and measured by the three-dimensional ultra-depth of field microscope. Fourier transform infrared spectroscopy (FTIR) was used to analyze the intermolecular interaction of polymer in the bonding interphase. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were applied to acquire the macroscopic differences in fracture morphology of two types of wood strips after pulling out, the microscopic failure mode of cell wall layers, as well as the initiation and diffusion of cracks.
ResultThe load-displacement curves of the pull-out test showed that brittle fracture occurred within the wood/PF bonding interphase. The interfacial shear strength of earlywood/PF resin was (1.23 ± 0.12) MPa, and that of early-latewood/PF resin was (3.66 ± 0.11) MPa, about three times that of earlywood/PF resin. FTIR analysis showed that the chemical cross-linking reaction between wood and PF resin polymer molecules was confirmed to enhance the bonding interphase property. SEM results showed that the fracture type of the earlywood sample on the top of the embedment was “shear failure? while that was “combined tension and shear on the bottom of the embedment. The fracture type of the early-latewood sample was mainly “splintering tension failure. AFM images showed that the failure of the earlywood strip was the “Intrawall failure? The initial crack occurred in the S
2layer of the adjacent tracheid wall with a significant thickness variation and then propagated along the S
1/S
2interface. The initial crack in the S
2layer of latewood cells of the early-latewood sample simultaneously expanded along the CML/S
1and S
1/S
2interfaces. In addition, stress concentration was prone to be in the cross-field region, and the external tension load made the ray cells peel off or fall off as a whole.
ConclusionThe difference of PF resin penetration in earlywood and latewood led to the shear strength difference between the two types of bonding interphase. The difference in structure and performance between earlywood and early-late wood was the main reason for the difference in fracture morphology at the interface after pulling out.
Abstract:
ObjectiveThe dominant strains with degradation ability to dimethoate (organic phosphorus), beta-cypermethrin (pyrethroids) and imidacloprid (neonicotinoid) were screened and the effects of the above pesticides on the growth of soil microbial populations were explored.
MethodThe sensitive bacteria were screened out by artificial application, and the phenotypic characteristics and 16S rDNA of the dominant bacteria with certain resistance to pesticides were identified by dilution coating method and continuous streaking method.
ResultThe dominant bacteria screened from the soil after pesticide treatment were mainly
Bacillus,
Chryseobacterium,
Pseudomonasand
Acinetobacter: C3 strain in
Bacillusdid not have colonies in the soil treated with 4.000 g/L dimethoate and 0.100 g/L imidacloprid at high mass concentrations; Strain C5 of
Acinetobacterdid not grow in 0.120 g/L, 0.040 g/L beta-cypermethrin and 0.100 g/L imidacloprid treatment groups; Strain C6 of
Pseudomonasdid not grow in 4.000 g/L dimethoate and 0.050 g/L and 0.017 g/L imidacloprid-treated soils. Different concentrations of pesticides have different degrees of inhibition on soil colonies. The inhibition rate of bacterial and fungal colonies in soil was positively correlated with the concentration, and the inhibition rate showed a decreasing trend over time. On the 14
thday, only 0.100 g/L imidacloprid treatment group did not recover to the normal level. In the treatment groups of dimethoate and imidacloprid in fungi, the number of fungal colonies in the low concentration soils on the 14
thday was significantly higher than that in the high concentration soils (
P< 0.05).
ConclusionThere were dominant bacteria with certain resistance to dimethoate, beta-cypermethrin and imidacloprid pesticides in soils, provide theoretical basis for directional culture of excellent strains; The inhibitory effects of different pesticides on the number of soil fungi and bacterial colonies were also different, and the inhibitory effects were as follows: imidacloprid > dimethoate > beta-cypermethrin. Moreover, imidacloprid had the highest inhibitory effect on the number of soil bacteria, and had little effect on soil fungi.
Abstract:
ObjectiveSucrose invertase, as a key enzyme in plant sucrose metabolism, plays an important role in plant growth and development. In this study,
PtoNIN1, an alkaline/neutral invertase, was selected to do detailed analysis, including gene cloning, bioinformatics, gene expression and genetic transformation analysis, and these results are helpful for clarifying the mechanism of sucrose metabolism in
Populus tomentosa.
Method
PtoNIN1 was obtained through the homologous cloning of
PtrNIN1 in
P. trichocarpa, and then bioinformatics analysis for
PtoNIN1 were carried out. Gene expression of
PtoNIN1 was conducted at different organs (leaf, stem, root and mature leaves) and different developmental stages of male and female flower buds. And overexpression vector of
PtoNIN1 was constructed to carry out genetic transformation research on the model plant
Arabidopsis thaliana.
ResultThe coding region of
PtoNIN1 was 2 073 bp in length. The PtoNIN1 protein contained 690 amino acids, and its molecular weight was 77.80 kDa.
PtoNIN1 contained a specific domain of glycosyl hydrolase supergene family 100. The phylogenetic analysis showed that it is the member of mitochondrial-type invertase cluster.
PtoNIN1 was widely expressed in the plant, including roots, stems, leaves, mature leaves, male and female flower buds. Thereinto, the development stage of male and female flower buds had an influence on the expression of
PtoNIN1. Genetic transformation studies in
Arabidopsisshowed that overexpression of
PtoNIN1 significantly increased the fresh weight of rosette leaves, stems and siliques. The sucrose contents in stems and siliques of transgenic plants were also significantly increased. And higher expression patterns of other sucrose metabolism-related genes were found in transgenic plants when compared with wild-type plant.
Conclusion
PtoNIN1 is the member of mitochondrial-type invertases in
P. tomentosa. It is widely expressed in various tissues of poplar, and has a specific expression in the early developmental stage of male and female inflorescences. Overexpression of
PtoNIN1 in
Arabidopsiscan significantly increase plant biomass accumulation. This study provides a reference for the functional verification of other invertases in poplar, and lays a foundation for revealing the sucrose metabolic process of poplar.
Abstract:
ObjectiveTo discuss the historical distribution changes of
Corylus heterophyllaFisch. complex ＇i>Corylus heterophyllaFisch,
Corylus kweichowensisHu,
Corylus yunnanensisA. Camus.）since the last interglacial, and understand the response mechanism of its geographical distribution to environmental evolution, so as to provide reference for clarifying the evolutionary relationship of three species, and also provide scientific basis for resource protection and development.
MethodBased on the distribution data of the three species of
C. heterophyllacomplex and the corresponding environmental variables, MaxEnt model and ArcGIS software were used to simulate their potential distribution in the last interglacial, last glacial maximum, mid-Holocene and modern times to explore its historical distribution changes; then, the distribution areas of three related species in different periods were superimposed to speculate their ice age refuge, which was verified by hazel pollen data. Finally, the niche differentiation among the three related species was detected by principal component analysis, and the main environmental impact factors were comprehensively evaluated.
ResultOn the whole, the contribution of the first two environmental factors affecting the distribution of
C.
heterophyllaand C.
kweichowensisis similar, while the first two main environmental factors of
C. yunnanensisare related to water. Compared with temperature, water has a more important impact on the distribution of the three tree species. In terms of the suitable areas,
C. heterophyllaof northern China experienced glacial contraction and interglacial expansion during the Quaternary, whereas
C. kweichowensisand
C. yunnanensisof southern China presented population expansion even during the last glacial maximum. The refuges of the three related species obtained after overlapping of the suitable areas are in good agreement with the palynological results.
ConclusionThis study accurately simulates the distribution changes of
C.
heterophyllacomplex in four historical periods, explores its ecological differentiation, and speculates on its biological refuge, which provides some scientific basis for the conservation and management of the resources in China under the background of future climate change.
Abstract:
ObjectiveBased on multi-scale segmentation and tasseled cap transformation, to develop a detection method for forest cover change in complex plateau area.
MethodThis paper applied Landsat 5 TM and Landsat 8 OLI multi-spectral images, taking the transition mountain zone of Middle East Yunnan Plateau as the study area, based on multi-scale segmentation, using the tasseled Cap transformation (TCT) and principal component analysis (PCA), to transform the multi-feature change vector, determine the optimal threshold, extract the forest coverage change information, and verify the accuracy of the results.
Result(1) The overall accuracy of the test results by PMKT-D was 92.32%, and the Kappa coefficient was 0.843 7, which was significantly better than the control method. (2) From 2010 to 2020, the area of forest cover change in the transition mountain zone of Middle East Yunnan Plateau was 356.88 km
2, accounting for 1.06% of the total image area, indicating significant changes of forest cover.
ConclusionBased on multi-scale segmentation, The method combining TCT and PCA can effectively reduce the adverse effects of complex topography and phenology, enhance spectral characteristics of forest cover changes and improve the accuracy of the change detection significantly while take advantages of object-oriented multi-feature change vector.
Abstract:
ObjectiveThis research was carried out to explore the differences and reasons of moisture sorption thermodynamics between archaeological wood and recent wood, and provide a theoretical basis for the protection and research of excavated archaeological wood, and be conducive to improving the dimensional stability of the unearthed moisture-saturated wooden relics.
MethodAncient and recent cypress (
Cupressussp.) were used as research objects, and the microscopic morphology and chemical groups of the wood samples were characterized by scanning electron microscope and fourier transform infrared spectroscopy respectively. The adsorption and desorption isotherms for both wood at 25 and 50 were measured by dynamic vapor sorption, and fitted based on the Hailwood-Horrobin moisture sorption theory. The differential adsorption heat
Q
S, Gibbs free energy change Δ
Gand differential adsorption entropy Δ
Sof the wood samples were calculated by Clausius-Clapeyron formula, to analyze the discrepancy of sorption thermodynamics between archaeological and recent wood.
ResultCompared with recent wood, the cell wall of archaeological wood was decayed obviously. A large number of cell wall pores and mycelia were found. The cellulose and hemicellulose were degraded seriously with increased relative content for lignin. The content of polar group −OH and −COOH decreased. Under certain temperature conditions, the equilibrium moisture content of archaeological wood was higher than that of recent wood, while the values of
Q
Sand Δ
Swere lower than that of recent wood, and an inflection point occurred at the moisture content of 5%, corresponding to a saturation of the monolayer water. On the other hand, there was little difference in Δ
Gbetween archaeological wood and recent wood. The values of
Q
S, Δ
Gand Δ
Sof archaeological wood in hygroscopic equilibrium state are lower than those in desorption equilibrium state.
ConclusionIn this study, it was found that the cell wall structure of archaeological wood decayed after a long time of corrosion. Compared with recent wood, the degradation degree of cellulose and hemicellulose in archaeological wood was the greatest. And the moisture sorption of archaeological wood reduced. Under certain temperature conditions, the hygroscopicity of archaeological wood was higher than that of recent wood, but its thermodynamic values were lower. There were thermodynamic sorption hysteresis of archaeological wood.
Abstract:
ObjectiveThe large microfibril angle (MFA) in the S
2layer of the compression wood cell wall is the result of the adaptive growth of tree tracheids to the mechanical stimulation, so it has special mechanical functions. However, the toughening mechanisms of large MFA in S
2layer on the compressive properties of wood cell wall has not been understood yet by researchers. Based on a computational model of composite material for the ultrastructure of S
2layer of the compression wood cell wall, the effect of the MFA in S
2layer on the compressive toughness of compression wood cell wall was simulated and the toughening mechanism was explored, and the method of modeling and analyzing the compressive toughness of the wood cell wall based on the numerical model was explored. The findings presented in this paper would provide useful guideline for the optimal design of biomimetic materials.
MethodFirst, the S
2layer of spruce wood cell wall was modeled as a composite cylinder composed of continuous microfibrils as well matrix, and the equivalent elastic constants of the matrix of S
2layer were calculated using the self-consistent model of inclusion theory. Then, the finite element analysis model of the fiber reinforced composite of wood cell wall was established by using HyperWorks. The compressive mechanical behaviors of the S
2layers of compression wood and normal wood with different MFA were simulated by using Abaqus, and the relationship between MFA and the compressive toughness of S
2layer was analyzed. On this basis, the compressive mechanical behaviors of wood cell wall with and without S
1, S
2L and MP layers were investigated, and the importance of considering the plastic behavior of each constituent in the numerical model of compression wood cell wall was analyzed.
ResultAs the increasing of MFA in S
2layer, the critical buckling displacement of S
2layer of wood cell wall is increasing, and the critical buckling pressure is first decreasing and then increasing. The critical pressure of S
2layer of compression wood cell wall with MFA of 45° is equivalent to that of normal wood cell wall with MFA = 0°, but the critical buckling displacement of the former is 3.57 times that of the latter, and the strain energy before buckling is 2.95 times that of the latter. Under the same pressure, the von Mises stress of microfibrils in the compression wood S
2layer with MFA = 45° is lower than that in the normal wood S
2layer with MFA = 0°. The compressive stiffness and compressive toughness of S
2layer with large MFA are enhanced because the compression-torsion coupling of spiral microfibrils in S
2layer of a single compression wood cell wall is constrained by its surrounding tracheids. S
1, S
2L and MP layers have significant restraint effect on the buckling of the compression wood cell wall, and the critical pressure of the compression wood cell wall with the consideration of all the layers in the wood cell wall is 37.6% larger than that of the model only considering the S
2layer. The failure mode of wood cell wall under pressure is of plastic buckling, so it is very important to include the plastic behavior of each component of wood cell wall to accurately calculate its compressive toughness. Ignoring the plastic behavior of wood cell wall will cause the computed result of its critical pressure increased by 2.97 times.
ConclusionThe spiral morphology of microfibrils in the S
2layer of compression wood cell wall changes the stress transfer between the microfibrils and the matrix, which results in the matrix of the S
2layer bearing more compressive stress and the failure mode of the wood cell wall becoming local plastic buckling. Although the compressive stiffness of compression wood cell wall decreases with the increase of MFA in S
2layer, the critical buckling displacement of cell wall increases significantly with the increase of MFA, thereby the compressive toughness of S
2layer is enhanced. When MFA is about 45°, the compressive toughness of S
2layer of compression wood cell wall reaches the highest, not only its critical buckling displacement is more than twice that of S
2layer of normal wood cell wall, but also its critical buckling pressure is slightly higher than the latter.
Abstract:
ObjectiveThe tree height curve of main tree species was established based on tree classification, which provided reference for studying the growth law of
Larix gmelinii, and provided technical support for forest sustainable management in Daxing’anling Mountains.
MethodBased on the data of 56 fixed plots in Cuigang Forest farm of Daxing’anling Mountains, trees were divided into three grades of dominant, average and crushed trees according to the relative diameter
dof individual trees. Based on the adjusted coefficient (
R
2
adj), root mean square error (RMSE) and the largest red pool information (AIC) selected
Larix gmeliniilevel of the champion tree high each curve based model, and further evaluation and comparison of quantile regression and dummy variable regression trees of different levels of various tree species tree height curve model to simulate the influence of precision.
ResultThe optimal basic models of
Larix gmeliniiheight curves are Wykoff equation. When the dumb variables of stand classification were added to parameters
aand
bof Wykoff equation, the model had the best fitting effect. The adjustment coefficient(
R
2
adj), root mean square error (RMSE) and red pool information (AIC) of
Larix gmeliniitree species curve model were 0.858 8, 1.642 4 and 2 081.902, respectively. There was no difference between the optimal quantile model and the whole stand of
Larix gmelinii, and the median model was optimal (
τ= 0.5). The three statistics of height curve of the deciduous pine were 0.849 8, 1.693 8 and 2 211.037, respectively. Through comparative analysis, the tree height curve model with tree classification as dummy variable has the best fitting effect.
ConclusionIncluding forest tree species classification in Daxing’anling Mountains dummy variable tree height curve model fitting effect is superior to the basic model, and has better prediction precision and adaptability, can reflect the different level of forest tree height, DBH growth difference, can for Daxing’anling Mountains region
Larix gmelinii, provide theoretical basis for the management and growth forecasts.
,Available online,
doi:10.12171/j.1000-1522.20210416
Abstract:
ObjectiveThis study mainly focuses on continuous mating ability, the effects of adult stage and mating experience on reproductive ability, and the effect of mating behavior on the lifespan in
Bursaphelenchus xylophilus. Our data showed the difference in reproductive strategies between male and female nematodes and clarified their mating characteristics, providing a novel idea of interfering mating behavior to control the population growth of
B. xylophilus.
MethodThe synchronous virgin male and virgin female of
B. xylophiluswere obtained. The continuous mating ability of pine wood nematode was analyzed through continuous tracking observation and microscopic video playback.
B. xylophiluswere collected on days 3, 5 and 7 after sexual maturity and at different mating experience. Their mating success rate and average egg production were counted separately for analysis of the effects of adult stage and mating experience on the reproductive ability. And the lifespan of virgin male and female and mated male and female nematodes was quantified.
ResultIn
B. xylophilus, a virgin male could successfully mate with three virgin females in a row without feeding, and made them conceive and laid eggs. However, after successfully mating, virgin females laid eggs first and did not mate continuously. For virgin male and female nematodes, both the mating success rate and average egg production decreased with the increase of adult stage. This reaching significant levels of difference at day 7 and day 5 after sexual maturity, respectively. Females were more significantly affected by adult stage than males were. There were significant differences in the mating success rate of males and females of
B. xylophiluswith different mating experience. For virgin males and females on day 3 after sexual maturity, they were (60.00% ± 9.43%) and 100%, respectively. For mated males and females of the same adult stage, they were significantly reduced to (17.50% ± 4.68%) and (25.00% ± 2.34%), respectively. However, there was no significant difference in their average egg production. In addition, the mating behavior had no significant impact on the lifespan of pine wood nematode. For virgin and mated females, the average lifespan was (24.47 ± 0.22) days and (24.93 ± 0.70) days, respectively. Whereas for virgin and mated males, it was (21.80 ± 0.54) days and (23.43 ± 0.78) days, respectively.
ConclusionIn
B. xylophilus, virgin males could mate multiple times in succession, while virgin females laid eggs first after mating. Moreover, both adult stage and mating experience significantly affected their mating success rate, but average egg production is only affected by adult stage. However, mating behavior did not accelerate their senescence. This study clarified the mating characteristics of
B. xylophilusand laid a theoretical foundation for exploring its molecular regulation mechanism.
,Available online,
doi:10.12171/j.1000-1522.20210483
Abstract:
ObjectiveA scalable altimeter was developed to solve the limited landing range of measuring tree height based on trigonometric function and to realize accuracy measurement of vertical and inclined growth tree height.
MethodBased on principle of draw-wire sensor measuring tree height, the scalable altimeter was developed, of which main structure contains optical electricity encoder , brushless DC motor, coil and rope. The tree height measured by linen tape was taken as true value. A total of 20 vertical growth trees and 11 inclined growth trees were measured by scalable altimeter, Blume-Leiss altimeter and forest compass to compare the measurement precision, variance and
tresult respectively. The tree height of No. 8 sample (vertical growth tree) and No. 26 sample (inclined growth tree) were measured continuously to test the measurement accuracy by 6 times.
ResultThe results demonstrated that the precision of scalable altimeter in measuring vertical and inclined growth tree height was 0.034 and 0.028 m. The variance of scalable altimeter in measuring vertical and inclined growth tree height was 5.60 and 9.94. The accuracy of scalable altimeter in measuring vertical and inclined growth tree height was 0.028 and 0.015 m. The precision of Blume-Leiss altimeter in measuring vertical and inclined growth tree height was 0.154 and 0.267 m. The variance of Blume-Leiss altimeter in measuring vertical and inclined growth tree height was 5.76 and 10.00. The accuracy of Blume-Leiss altimeter in measuring vertical and inclined growth tree height was 0.150 and 0.125 m. The precision of forest compass in measuring vertical and inclined growth tree height was 0.059 and 0.183 m. The variance of forest compass in measuring vertical and inclined growth tree height was 5.66 and 10.02. The accuracy of forest compass in measuring vertical and inclined growth tree height was 0.056 and 0.066 m.
ConclusionThe measurement results of scalable altimeter had better measuring precision than Blume-Leiss altimeter and forest compass. The development of scalable altimeter would not only solve the problem of disconnection between field investigation and internal entry, but also meet the requirements of standing tree height measurement in national continuous forest inventory and forest management inventory effectively.
Abstract:
Objective
Broussonetia papyriferais an important ecological and economic species, which is widely planted in karst areas. However, at present, research on the impact of cutting patterns on its yield and quality is seldom, resulting in low resource utilization, low yield and quality of
Broussonetia papyriferastand. Therefore, this research study the effects of different cutting frequencies and stubble heights on the yield and nutrient content of paper mulberry, in order to determine the optimal cutting mode and guide the harvesting and utilization of
Broussonetia papyrifera.
MethodsResearch objects were two-year-old paper mulberry in Zhenfeng County, Guizhou Province. Three cutting frequencies (cutting 3 times, 4 times and 5 times a year) and three stubble heights (stubble 0 cm, 15 cm and 30 cm) were randomly set up. The number of sprouting, biomass of harvested branches and leaves, crude protein and crude fat content among different treatments were studied.
ResultsThe number of resprouting of
Broussonetia papyriferaunder 4 and 5 times cutting a year was significantly higher than 3 times. With the increase of cutting times and stubble heights, stem to leaf ratio decreased gradually. The biomass, crude protein were not affected by cutting frequency. However, stubble heights significantly affect biomass, and showed that biomass of stubble 30 cm was the highest (2.63 t/ha). The crude fat content of neat cutting was significantly higher than that of stubble 15 cm and 30 cm.
ConclusionThere was little difference in yield and quality of
Broussonetia papyriferaamong 3 ~ 5 times cutting a year. Yield with stubble of 30 cm was the highest, but the crude fat content decreased slightly. Therefore, it is recommended that cutting 3 ~ 4 times a year and stubble height 30 cm for harvesting and utilization in paper mulberry forage forest.
Abstract:
ObjectiveWater retention is one of the most important ecosystem services closely related to human beings, and it is also an important index to evaluate the regional ecological environment benefits. This study takes the amount of water retention as an index to explore the ecological benefits of the implementation of the Beijing-Tianjin Sandstorm Source Control Project Area (BTSSCPA).
MethodWe evaluated the impacts of land use/cover change on water retention services using regional land use/cover and meteorological data from 2000 to 2018.
Result(1) The land use/cover in the BTSSCPA indicated a spatial heterogeneity with large area of grassland, cropland and woodland, and the amount of water retention increased from northwest to southeast. (2) From 2000 to 2018, forest land increased by 14.22%, and the amount of regional water retention also showed an increasing trend. The increase was relatively large in Northern Shanxi Mountains, Water conservation zone of Yanshan mountainous region, Horqin Sandy Land, Ordos Plateau and Southern Greater Hinggan Mountains. (3) The water retention service of regional ecosystem varied with different periods, sub-regional distribution and land type transformation, and the water retention service of woodland was the highest, and it was dominant in all sub-regions. (4) From 2000 to 2010, the transfer of grassland to woodland made the greatest contribution to the increase of water retention, reaching 49.32 × 10
8m
3. The conversion of a large area of grassland to woodland increased the water retention capacity most significantly in the Southern Greater Hinggan Mountains, reaching 16.11 × 10
8m
3. (5) From 2010 to 2018, the transfer of grassland to woodland made the greatest contribution to the increase of water retention, reaching 3.87 × 10
8m
3. The contribution of reclamation, afforestation and grass planting of wasteland to water retention concentrated on the southern Ordos Plateau, increasing by 1.31 × 10
8m
3, Returning farmland to forest and grassland transfer to woodland made the greatest contribution to Water conservation zone of Yanshan mountainous region, up to 1.84 × 10
8m
3.
ConclusionSince the implementation of the BTSSCPA, the measures such as returning farmland to forest, wasteland afforestation and grassland management have effectively improved the water retention service in the study area. The main types of land use/cover transfer that lead to the increase of water retention are the transfer of unused land to woodland and grassland and the transfer of grassland and cropland to woodland. The areas with the greatest contribution to the increase of water retention by land use/cover transfer are mainly in the Southern Greater Hinggan Mountains, Water conservation zone of Yanshan mountainous region, Northern Shanxi Mountains and other southeastern regions. The regional land use/cover pattern needs to be further optimized. The implementation of the next phase of the project program should be based on the ecological characteristics of each district, to implement the project of returning farmland to forest and grassland in areas with weak water retention service capacity, to improve cultivation measures for soil and water conservation on cropland that needs to be preserved, to scientifically implement sand sealing, forestry and grass cultivation or artificial afforestation in areas with large unused land area according to the carrying capacity of water resources, and to strengthen the management and protection, so that the high ecological benefit areas in the study area will continue to develop steadily, while the low ecological benefit areas will focus on treatment and efficient development.
,Available online,
doi:10.12171/j.1000-1522.20220419
Abstract:
ObjectiveTo solve the problems of poor recognition and low efficiency of surface defects of wood panel lumber by manual and traditional digital image processing methods, and to improve the utilization rate of wood. Based on the deep learning model, we construct a wood panel surface defect detection system, aiming to expand the application of deep learning model in the field of wood panel defect detection.
MethodsBased on 839 wood panel defect images in the public dataset “Wood Defect Database? the dataset is expanded using Imgaug data enhancement library; by introducing SE attention mechanism in the backbone feature network part, the YOLOv5 wood panel surface defect target detection framework is constructed using focus, FPN + PAN structure, and then the transfer learning idea to improve the training method and divide the training process into two phases (freezing phase and unfreezing phase). Then the constructed model is compared with the current mainstream deep learning target detection models, and finally the model is evaluated using confusion matrix, Loss value change curve, model size, detection time, and mean average accuracy.
ResultsA detection method based on YOLOv5 model for live knots, dead knots, cracks and holes in wood panel surface defects is proposed. The mean average accuracy of the model for dead knots, live knots, cracks, and holes identification results are about 98.66%?9.06%?8.10% and 96.53, respectively, and compared with the current mainstream detection models, the improved model has better accuracy, recall, and combined average accuracy of 97.48%, 96.53%and 98.22%, respectively. The average detection time of the model for a single image is 10.3 ms, and the maximum detection time is 20.5 ms. The detection effect and generalization characteristics are better, and the model occupies only 13.7 MB of memory, which is easy to be ported.
ConclusionThe experiments indicate that the improved YOLOv5 model can be used to detect the main defects on the surface of wood paneling. The model is better than the other five mainstream inspection models in identifying surface defects. On the basis of maintaining the original detection accuracy, it improves the recognition of small target defects, reduces the situation of missing wood panel defects, and realizes fast detection in complex scenes.
Abstract:
ObjectiveTo study the dynamics of nitrogen (N), phosphorus (P), and potassium (K) nutrients in moso bamboo forest after strip cut, so as to provide a scientific basis for nutrient management strategies in the post cut bamboo forest.
MethodWe selected the plots that strip cut with 8 m width (SC) and its reserved belts (RB) as the research object and the traditional management forest (CK) as control. The biomass of moso bamboo, understory vegetation, litter yield, and corresponding nutrient contents of each component was investigated for five years after cutting. Therefore, nutrient flux was quantified, and the nutrient cycling coefficient of the moso bamboo forest was calculated. The characteristics of nutrient flow and cycling were compared among different treatment plots.
Result(1) In the first year after cutting, there was no significant difference in the retention of N, P, and K among different treatment plots. The return of nitrogen in SC was decreased; (2) Three years after cutting, the retention of nitrogen in the RB was less than that in the SC and CK; The return of nitrogen in SC and RB was significantly lower than that in CK. (3) Five years after cutting, the retention of nitrogen in RB was less than that in SC and CK; There was no significant difference in the amount of N, P and K returned and nutrient storage between the SC and CK. (4) Strip cutting significantly increased the utilization coefficients of N, P and K (
P< 0.05). With the restoration of the plots, the utilization coefficient of each nutrient gradually decreased, and there was no difference with CK; The utilization coefficients of nutrients in RB decreased significantly with the growth of bamboo forest (
P< 0.05); Cutting had no significant effect on the cycling coefficients of N, P and K, but the cycling coefficients of nutrients in RB gradually increased with time.
ConclusionFive years after cutting, nitrogen, phosphorus, and potassium nutrient storage reached the level of the pre-cutting and CK. From the perspective of the nutrient cycle, it was proved that SC could recover to the level of CK after 5 years. However, the nutrient use coefficient and recycling coefficient of RB gradually decreased from the second On-year after cutting, and density control management was needed to improve the nutrient use efficiency.
,Available online,
doi:10.12171/j.1000-1522.20210323
Abstract:
ObjectiveIn order to explore the composition, content difference and correlation of the components of pecans, and to provide a reference for the mining of superior germplasm resources and the breeding of superior new clones.
MethodsThe oil content, fatty acid, phenolic substances content, drupe mass, drupe height, drupe diameter, and kernel mass of 50 clones were measured to analyze the correlation among the traits, and comprehensive evaluation was made based on the principal component analysis model.
Results(1) the oil content ranged from 70.09% to 79.99%, among which the mean oil content of JD25, JD13, JD6, JH3, JD23, XS3, JD27 and JD28 was higher. (2) A total of 8 kinds of fatty acids were detected, and the relative contents of fatty acids were different, among which the contents of JH1, JD21, XS3, JD27 and XS7 unsaturated fatty acids were higher than those of other varieties. (3) There were significant differences among each trait, and the variation coefficient of unsaturated fatty acids was 0.38%, which was the stablest. The coefficient of variation of total flavonoids and condensed tannin were 51.22% and 49.88%, which were high variable. (4) Principal component analysis was used to comprehensively evaluate 50 clones, among which XS12, XS1, JD23, XS3, JH1, XS8, JD30 and JD29 ranked the top.
ConclusionConsidering the oil content and the ranking of the principal component analysis model, the top three clones and the clones common to both, namely JD23, XS3, XS12, XS1, JD25, JD13 and JD6, were selected as excellent germplasm resources and clones for breeding.
Abstract:
ObjectiveThis paper aims to establish mixed effect beta regression models for sapwood, heartwood, bark and stem density of
Populus nigra × P. simonii, which based on the analytical data of 90 trees of
P. nigrax × P. Simoniiplantation in Shangzhi City, Heilongjiang Province.
MethodsUsing correlation analysis and optimal subset methods to screen the variables of the beta regression base model, and the goodness of fit of the convergence model was evaluated by ?log-likehood value, akaike information criterion, bayesian information criterion, adjusted certainty coefficient (
R
a
2) and likelihood ratio test. The Leave-one-out-cross-validation was used to test the model, the indexes are mean absolute error (MAE) and mean absolute error percentage. Two sampling methods were combined (scheme ⅟ no relative height, scheme Ⅰ limit relative height below 0.1 to correct the model.
ResultsThe density of sapwood, heartwood, bark and stem were not only affected by relative height, but also closely related to the average growth of breast diameter, age and breast diameter, respectively, and the
R
a
2of the mixed-effect beta regression model based on tree factors was 0.53, 0.52, 0.52, 0.63, and the MAE < 0.05 g/cm
3, which improved the prediction accuracy compared with the basic model. Sapwood density and heartwood density increased along the stem base, and decreased first and then increased. There was an inflection point at the relative height of 0.2. The bark density first increases and then decreases from the base of the stem to the top of the tree, and there is an inflection point at the relative height of 0.6. The stem density increases gradually along the stem. When fixed relative height, the density of sapwood, heartwood, bark and stem was negatively correlated with the average growth of DBH, age and DBH respectively. Without limiting the relative height, the wood density value corresponding to the height of 4 discs randomly sampled along the stem was calibrated to obtain stable prediction accuracy. When the sampling height is limited to 0.1 (2.0 m) or less, there is little difference in the prediction accuracy between the optimal sampling combination and the density values (1.0, 1.3, 2.0, 1.0 m respectively) of sapwood, heartwood, bark and stem at a disc height.
ConclusionRelative height, average growth of breast diameter, age and breast diameter were significant influencing factors of wood density of
P. nigra × P. simonii.The beta regression model can directly simulate the stem density of
P. nigra × P. simoniiin the (0, 1) interval, and the random effect can improve the prediction accuracy of the model. The longitudinal variations of sapwood, heartwood, bark and stem density are different. The constructed mixed-effect beta regression model can lay a foundation for biomass estimation and wood property study of
P. nigra × P. simonii.
Abstract:
ObjectiveThe ecological significance of 4-variate distribution of stand spatial structure parameters was deeply analyzed and a comprehensive evaluation index of stand spatial structure diversity based on the relationship between adjacent trees was constructed to provide a theoretical basis for formulating targeted forest structure adjustment strategies.
MethodBased on the concept of biodiversity, taking the structural unit which composed by reference tree and its nearest four adjacent trees as the object, organically integrate the 4-variate distribution of structural parameters of uniform angle index, mingling, neighborhood comparison and crowding, as well as the number of structural unit trees and forest layers, the genetic absolute distance formula and natural logarithm are used to express the evenness and richness of structural unit types, respectively, and the stand spatial structure diversity index was constructed. The validity of the index was verified by using the long-term positioning monitoring sample plot data
ResultUsed the stand spatial structure diversity index (FSD) proposed in this study to measure the spatial structure diversity of forest types in different climatic zones or different origins show that the FSD values of
Quercus alienavar.
acutiserratanatural forest (0.854) and broad-leaved
Pinus koraiensisforest (0.852) were almost the same, indicating that the two forest stands have similar spatial structural diversity. The 4-variate distribution types of
Platycladus orientalisplantation was higher than other natural forest, however, its spatial structural diversity (FSD = 0.382) was the lowest in the three stand types, mainly due to its lower diversity in both vertical (FSD
v= 0.369) and horizontal (FSD
h= 0.562) structure than the two natural forest stands. The average number of tree species in the structural units was higher in natural forest than in plantation, with 4.23 in
Quercus alienavar
. acutiserrataforest, 4.09 in
Pinus koraiensisforest, and 1.98 in
Platycladus orientalisplantation. The number of tree species in a structural unit fully demonstrate species richness of the structural unit.
ConclusionThe integration of the three numbers including 4-variate distribution of stand spatial structure parameters, the number of tree species and number of forest layers in structure unit, lays the foundation for constructing a valid spatial structure diversity index for forest stands. The stand spatial structural diversity index (FSD), based on the concept of biodiversity, is not only a feasible quantitative expression of the 4-variate distribution of structural parameters, but also is an appropriate interpretation of the ecological significance of the 4-variate distribution of structural parameters, and a comprehensive scientific evaluation of the spatial structural diversity of the stand. The index is able to measure the difference of stand spatial structure diversity of different stand types.
Abstract:
Objective
Pinus massonianais one of the important fast-growing timber species in south China. In this study, phenotypic and genetic stability of DBH and tree height traits of 10
Pinus massonianaclones were studied at multiple sites, and excellent genotypes with high genetic gain were screened, so as to provide experimental basis for efficient cultivation of
Pinus massonianawith suitable genotypes and quality and efficiency improvement of plantation.
MethodThe DBH and tree height of 10 3-year-old
Pinus massonianaclones (M1 ~ M10) were measured from regional experimental forest in Ningming County (E1), Liuzhou City (E2), Bobai County (E3) and Qinzhou City (E4) of Guangxi. The growth traits and phenotypic variation of different genotypes were analyzed. Clone stability analysis and comprehensive evaluation were carried out to screen excellent genotypes with high productivity and good stability.
ResultThe growth variation of
Pinus massonianaclones was rich, the total varation of DBH between clones at the same site and between clones at the same site was greater than tree height. Multi-point joint variance analysis showed that genotype, environmental conditions and genotype-environment interaction had significant effects on DBH and tree height growth of
Pinus massonianaclones (
P< 0.01). The growth performance of clones within the test site was different, and the growth performance of clones among different test sites was also different. The repeatability of DBH and treed height of clones at different sites was between 0.59 and 0.89, indicating they were mainly controlled by heredity. The results of genetic stability analysis showed that the DBH and tree height of M1, M2, M4, M5 and M7 clones grew faster and had good stability. Clone M8 had a special adaptability to the test site at Ningming County. Five superior clones (M1, M2, M4, M5, M7) were selected by comprehensive evaluation of DBH and tree height across four experimental sites. The genetic gains of DBH and treed height were increased by 37.90% ~ 45.65% and 21.92% ~ 24.38%, respectively, compared with the performance of seed orchard seedlings.
ConclusionThe DBH and tree height of
Pinus massonianavaried greatly among clones. Genotype, environment and the interaction between genotype and environment had significant effect on the growth traits of
Pinus massonianaclones. The five clones, M1, M2, M4, M5 and M7, grew rapidly and stably, and brought high genetic gain, which could be appropriately promoted in
Pinus massonianacultivation areas.
Abstract:
ObjectivesIn order to select the appropriate reference gene and analyze the role of jasmonic acid in
Rosaspecies and cultivars responding to
Marssonina rosae.
Methods
R. multifloraf.
carnea,
R. xanthinaf.
spontanea,
R.glauca,
R. rugosa,
R. hybrida‘Porcelina and
R12-26 (hybrid of
R. rugosaand
R. hybrida‘Porcelina? were used as material, qRT-PCR technology, geNorm, NormFinder, BestKeeper were used to evaluate the expression stability of nine candidate reference genes (
ACT,
GAPDH,
PP2
A,
RCl2,
SAND,
TIP,
TUA,
TUBand
UBC). The expression levels of jasmonic acid resistance pathway related genes (
COI1,
OPR3,
MYC2 and
JAR1) in six
Rosaspecies and cultivars were quantitatively analyzed.
Result(1)
UBCwas the common reference gene of six
Rosaspecies and cultivars responding to
M.
rosae, and can be used for analysis the related genes expression levels to JA resistance pathway. (2) There were differences in JA content among the six plants responding to
M.
rosae. In disease-resistant plants, JA concentration decreased at 0? d and increased at 4? d. In disease- susceptible plants, JA concentration decreased at 0? d and increased significantly at 8?0 d. (3) The expression levels of JA synthesis-related genes
OPR3 and
JAR1 were different at the early stage of infection. The expression level of
OPR3 was down-regulated and
JAR1 up-regulated in five plants except
R. multifloraf.
carnea.
OPR3 and
JAR1 were all up-regulated in the late stage of infection, however the up-regulation degree in black-spot susceptible species was significantly higher than that of resistant species. (4) There were also differences in the expression levels of JA signaling related gene
COI1 and
MYC2 at the early stage of infection. The expression of
COI1 was up-regulated in disease-resistant plants and down-regulated in disease-susceptible plants at the early stage of infection,
MYC2 was down-regulated in 6 plants infected 0? days.
COI1 and
MYC2 were up-regulated after 2 days of infection, and the up-regulation degree in black-spot susceptible species was significantly higher than that of resistant species.
ConclusionsWe believe that
MYC2 and
COI1, which are related to JA signal transmissions, play a negative role in regulating black spot resistance in
Rosa, SA pathway mediated resistance to necrotrophic fungi played a role in the late stage of infection.
Abstract:
ObjectiveClimate factors affect tree growth and development. The relationship between tree radial growth and climate factors is analyzed to explore the response of spruce fir coniferous and broad-leaved mixed forest ecosystem to climate change in Changbai Mountain, so as to provide scientific basis for natural forest management in this area.
MethodIn this study, we used dendrochronological techniques to sample tree-ring cores of
Abies nephrolepis,
Picea jezoensisand
Pinus koraiensis, which are the common species in the spruce-fir mixed stand in Wangqing County, Jilin Province in 2019. We developed tree-ring width chronologies of three conifers and conducted growth-climate relationship analyses to reveal the influence of climate factors on tree radial growth.
ResultThe mean sensitivity and signal-to-noise ratio of the three species are 0.16-0.27 and 6.14-19.98.
A. nephrolepiscontains more climate information, because the mean sensitivity, standard deviation, signal-to-noise ratio and expressed population signal of the standard chronology of it are higher than
P. jezoensisand
P. koraiensis. The average temperature in September of the previous year and the minimum temperature in July of the previous year and the current year were significantly positively correlated with the radial growth of three species (
P< 0.05), which indicates that climate has a similar effect on the ring width growth in the same area. The responses have a certain similarity. However, the response of radial growth of the three conifers to climate change was different too. The radial growth of
A. nephrolepisis affected by the combined effect of temperature and precipitation, while the radial growth of
P. jezoensisand
P. koraiensisis mainly restricted by temperature. After abrupt temperature rise (1985), the radial growth of the three species has an enhanced correlation with temperature but a weakened correlation with precipitation, and the radial growth of trees increased significantly.
ConclusionThe response of radial growth of different tree species to climate change has both similarities and differences, The increase in temperature may still be within the critical threshold of radial growth of
A. nephrolepis,
P. jezoensisand
P. koraiensis, so climate warming promotes their radial growth.
Abstract:
ObjectiveThis study is aimed at exploring the patterns of soil erodibility variation under the influence of preferential flow in the gully system of Jinsha River’s dry-hot valley, and, in doing so, revealing the interaction mechanism between soil and Water in the gully development area, so as to provide a theoretical basis for soil and water loss control and ecological restoration in dry-hot valleys.
MethodA complete gully in a typical gully development area of the dry-hot valley was selected as the research object. Based on dye tracing, soil erosion resistance and soil physicochemical experiments, statistical analysis methods such as principal component analysis (PCA) were used to obtain the soil preferential flow, soil erodibility indicators and their correlations, clarify the soil preferential flow characteristics of the complete gully system at the catchment area, gully wall, gully bed and gully bottom, as well as explore the correlation between preferential flow and soil erodibility.
ResultThe findings show that the preferential flow in the gully of the dry-hot valley was mainly “macropore flow? accompanied by “finger flow and “funnel flow? The percentage of preferential flow over the catchment area was found to be the highest, at 64.68%, followed in a descending order by gully wall, gully bed and gully bottom, which measure 46.96%, 32.08% and 31.55% respectively. This indicates that the development degree of preferential flow in the upstream of the gully is higher than that in the downstream. Moreover, the gully’s preferential flow area also features higher organic matter and soil moisture contents, better mechanical composition (clay, silt and sand), and lower soil bulk density relative to those in the matrix flow area. Also to take note is the soil anti-scour coefficient in the gully’s preferential flow area was smaller compared with that in the matrix flow area, suggesting that the preferential flow can reduce soil stability. Furthermore, the erosion resistance index of each gully section in the preferential flow area was higher than that in the matrix flow area, indicating that soil water and solute transport can improve local soil erosion resistance. The soil erodibility factor (K) of the gully system was positively correlated with the percentage of preferential pathway, the dry coverage of preferential pathway and the Maximum dyed depth. Additionally, PCA shows that the above three factors are all the main factors affecting soil erodibility.
ConclusionIn soil layers with high preferential flow development, the K in the preferential flow area is always higher than that in the matrix flow area, which is contrary to the soil layer with insufficient preferential flow development. This implies that the development of preferential flow improves soil erodibility to some extent.
Abstract:
Objective
Amygdalus pedunculatusis an important ecological and economic tree species in the sandy area of northern Shaanxi, which plays an important role in regional economy and ecological construction. In recent years, they have been disturbed by a variety of pests, and the damaged area is increasing and becoming more and more serious. In this study, the species and harm of
A.
pedunculatuspests in the sandy area of Northern Shaanxi were clarified, so as to provide basic data for the monitoring and scientific prevention and control of watermelon pests.
MethodFrom March 2017 to October 2020, pests of
A.
pedunculatuswere collected by manual collection and black light trap in the sandy area of Northern Shaanxi, and the collected pests specimen were identified, sorted and floristic analyzed. Then, the damage degree of pests was systematically investigated by standard field investigation method.
ResultThe results showed that there were 35 species of pests recorded belonging to 3 orders and 19 families in the sandy area of northern Shaanxi. Among them, 15 species belong to Coleoptera, accounting for 42.86%, 11 species belong to Hemiptera, accounting for 31.43%, and 9 species belong to Lepidoptera, accounting for 25.71%. The faunas analysis showed that The Palaearctic species of Coleoptera pests on
A.
pedunculatawere the most, accounting for 73.33%, and the widespread species of Lepidoptera and Hemiptera pests were the most, accounting for 88.89% and 81.82% respectively. The analysis of pest damage degree showed that there were 5 kinds of serious pests, 8 kinds of moderate pests and 22 kinds of light pests on
A.
pedunculata.
ConclusionColeoptera and Hemiptera are the main pests of
A. pedunculatain the sandy area of northern Shaanxi. Among them, Coleoptera pests are mainly Palaearctic species, while Hemiptera and Lepidoptera pests are mainly widespread species. The main pests on
A. pedunculatawere
Proagopertha lucidula,
Diglossotrox alashanicus,
Grapholitha funebranaand
Myzus persicae.
Abstract:
ObjectiveThe contents and ratios of carbon (C), nitrogen (N) and phosphorus (P) in plant leaves are the results of long-term adaptation of plants to the environment. Study of leaf stoichiometry characteristics of woody landscape plants in arid areas of northwest China can provide a data basis for the accurate planning and construction of large-scale models of planting in similar cities.
MethodIn this study, the C, N and P stoichiometric characteristics of 42 common woody landscape plants in the main urban district of Lanzhou (Qilihe, Anning and Xigu) were analyzed. The 42 plant species were classified into trees (26 species) and shrubs (16 species), evergreen (7 species) and deciduous (35 species), coniferous leaves (5 species) and broad-leaved (37 species). Variation characteristics of leaves’contents of C, N, P, C∶N, C∶P and N∶P of different life types were analyzed, and the relationship between the variation characteristics and specific leaf weight (LMA).
Results(1) The average content of C, N and P of 42 woody landscape plants were 39.67%, 2.45% and 0.17%, respectively. The average C∶N, C∶P and N∶P were 17.17, 232.98 and 14.72, respectively. Compared with the global scale, the contents of C and P and C∶N in leaves of woody plants in Lanzhou were relatively low, while the contents of N∶P in leaves were relatively high. (2) Stoichiometry characteristics are varied among plant life types. The C content, C∶N, C∶P and N:P of the leaves of trees are higher than those of shrubs, and the content of N and P is lower than that of shrubs. The leaf N and P content of deciduous tree species is higher than that of evergreen tree species. The leaves of broad-leaved tree species have higher leaf N and P content than coniferous tree species. (3) The analysis of the correlation between plant leaf traits showed that leaf C content was positively correlated with C∶N and C∶P (
P< 0.01). There was a synergistic relationship between LMA and leaf C content, but an opposite relationship between LMA and leaf N and P content.
ConclusionIt is preliminarily indicated that the development of woody landscape plants in Lanzhou are limited by N elements during the growing season, and it is suggested that nitrogenous fertilizer can be increased appropriately during the ecological environmental improvement in this area.
Abstract:
ObjectiveWith the acceleration of industrialization, many natural forests have been destroyed, leading to a significant decline in the quantity and quality of forests. Therefore, many measures have been taken to restore vegetation, mainly including artificial and natural restoration models. Studying the difference of soil water storage and nutrient storage of the forest under the two different restoration models will help to compare the advantages and disadvantages of these restoration models, and provide a theoretical basis for the subtropical vegetation restoration and reconstruction.
MethodIn this study, three typical forests were selected, namely, the secondary forest that had been naturally restored 35 years after precise cutting, the Chinese fir forest that had been naturally restored 39 years after artificial planting of Chinese fir, and the well preserved original forest, Compare the differences of water conservation and nutrient storage capacity of different restoration models.
ResultThe results showed that in terms of water storage capacity, the water holding capacity and saturated water storage capacity of Chinese fir forest and secondary forest were significantly lower than those of old-growth forest, but in terms of retained water storage capacity, Chinese fir forest and secondary forest were considerably higher than the old-growth forest, while there was a similar water storage capacity between Chinese fir forest and secondary forest; In terms of soil nutrient storage, the available nitrogen storage of old-growth forest and secondary forests were significantly higher than those of Chinese fir forests, but the available phosphorus storage of Chinese fir forests were considerably higher than those of secondary and old-growth forests; The carbon, total nitrogen and total phosphorus storages of the old-growth forest are significantly higher than those of Chinese fir forest and secondary forest, and the carbon storages and total nitrogen storages of Chinese fir forest are substantially higher than those of secondary forest, but the total phosphorus storages of Chinese fir forest are significantly lower than those of secondary forest.
ConclusionThe two restoration models are similar in soil water conservation but differ considerably in nutrient storage capacity. Different restoration models should be adopted according to the ecological restoration objectives. The natural restoration model should be used to improve available soil nitrogen and total phosphorus storages. The artificial restoration model can be applied to improve nutrient storages of available soil phosphorus, carbon, and total nitrogen.
,Available online,
doi:10.12171/j.1000-1522.20210498
Abstract:
ObjectiveThe effects of high temperature on microsporogenisis and cytological mechanism of pollen abortion induced by high temperature are conducted in
P. canescens, which aiming at improving the technology of forest triploid breeding though inducing gamete chromosme doubling by high temperature.
MethodIn this study, the effects of high temperature, meiotic stage and duration on percentage of aborted pollen were conducted after male flower buds were exposed to 38 for 3 or 6 h in
P. canescens. Subsequently, the differences in chromosome behaviour, meiotic microtubule cytoskeleton and development of tapetum between untreated pollen mother cells (PMCs) and treated PMCs were studied to reveal the cytological mechanism of aborted pollen production induced by high temperature.
Result(1) The results indicated that meiotic stages, temperature, duration, meiotic stage × temperature interactions and meiotic stage × duration interactions had significant effects on percentage of aborted pollen. The highest percentage of aborted pollen was 25.11 ± 4.28% when PMCs were treated with 41 for 3 h at metaphase ? (2) Compared with PMCs in the control group, meiotic microtubule cytoskeleton was depolymerized and some spindles were lost within the PMCs at metaphase and ? leading to the abnormal chromosome segregation at anaphase and and forming a great number of lagging chromosomes. These lagging chromosomes was retained within cytoplasm, causing some micronuclei to form. Therefore, aborted pollen formed due to the formation of polyads at tetrad stage. (3) Although high temperature could also delay the degradation of the tapetum, the anthers normally dehisced and pollen grains were released. Thus, the delayed degradation of the tapetum was not responsible for the formation of aborted pollen.
ConclusionAfter male flower buds was treated by 38 for 3 or 6 h, some spindles were lost within the PMCs at metaphase and ? leading to form a great number of lagging chromosomes and polyads, which was the cytological mechanism of aborted pollen formation induced by high temperature.
Abstract:
ObjectiveDisturbance and nitrogen deposition are important environmental factors influencing plant invasion. At present, studies on the synergistic effects of disturbance and nitrogen deposition on plant communities in wetland invaded by
Alternanthera philoxeroidesare relatively lacking. This study was to explore the short-term effects of disturbance, nitrogen deposition and wetland plant communities on
A. philoxeroidesinvasion, which established a strong theoretical support and practical foundation for the physical control of
A. philoxeroidesand the restoration and reconstruction of wetland vegetation.
MethodIn this study, invasive plant
A. philoxeroidesand four wetland plant communities, including
Myriophyllum aquaticum,
Scirpus validus,
Iris wilsoniiand
Lythrum salicariawere selected as the subjects. And three-factor control experiments were designed for invasive plant disturbance (no disturbance, simulated herbivory, mowing), nitrogen deposition (no nitrogen addition and with nitrogen addition), and native plant competition or not (only
A. philoxeroidesmodes, and
A. philoxeroidesand wetland plant communities composed by 4 plant species).
ResultSimulated herbivory and mowing had significantly reduced the growth and reproduction traits, including the relative growth rate basing on biomass, plant height and node number of
A. philoxeroides. And mowing had a greater impact than simulated herbivory. The growth rate of biomass, stem length and internode numbers of
A. philoxeroideswas negative under mowing, the compensation index of biomass, stem length and ramet numbers of
A. philoxeroideswas significantly lower than those of simulated herbivory treatment, but there was insufficient compensation. Furthermore, the wetland plant community significantly reduced the indexes including root, leaf, total biomass, leaf number, stem length and branch number of
A. philoxeroides. However, nitrogen deposition only significantly affected the compensation coefficient of
A. philoxeroidesbranching. Except for leaf number and branching compensation coefficient, there was no significant interaction between disturbance and nitrogen deposition on plant communities in the wetland invaded by
A. philoxeroides. talic> to a certain extent, and had a strong inhibitory effect on the growth and recovery of
A. philoxeroideswith the increase of interference intensity. Nitrogen deposition did not significantly affect the composite indicator of
A. philoxeroides. The local wetland plant community can inhibit the invasion of
A. philoxeroidesto a certain extent. Combined of the disturbance and nitrogen deposition only had a significant effect on the compensation coefficient of number of leaves and number of ramets, but had no significant effect on the wetland plant community invaded by
A. philoxeroides.
,Available online,
doi:10.12171/j.1000-1522.20210291
Abstract:
ObjectivesThe class peroxidase is a group of plant-specific oxidoreductases, and plays an important role in plant development and stress response. This paper presented a detailed overview of evolutionary and expression of olive class
PRXgene family, aiming to provide a reference for olive molecular breeding in the future.
MethodsWith some bioinformatic tools, we finished the identification of the olive class
PRXgenes, completed the analyses of the phylogenetic relationships, gene mapping on the chromosomes, pairs of duplicates, motifs, gene structure, cis-acting elements and gene expression in different tissues or biotic stresses, and did a verification of RNA-seq by RT-qPCR.
Results(1) 106 OePRX were obtained, and classified into 14 Groups based on the phylogeny with AtPRX and PtPRX. (2) OePRX were unevenly located on 23 chromosomes.The segmental duplication was a maining force driving in the expansion of OePRX gene family, and compared with
AtPRX,
OePRXhad a closer relationship with
PtPRX. (3) The characterization of pI, MW, motifs, gene structure, signal peptide, and expression in different tissue had the expected group-conserved patterns.The promoters of
OePRXcontained a variety of development and harmone elements; 38% of
OePRXgenes was differentially expressed in heat, drought and waterlogged stress.
ConclusionsThe differential expansion and differential expression may imply flexibility in neofunctionalization of duplicated class peroxidase genes that is of adaptive significance to the strong resistance of olive to a diversity of conditions, hence contributing to the importance of olive as a Mediterranean Basin staple food.
Abstract:
ObjectiveIn order to solve the problem of understory regeneration of
Larix principis-rupprechtiiplantation in Saihanba Area of Hebei Province, northern China and realize the near-natural management of plantation, it is necessary to study the effects of artificial promotion measures (hereinafter referred to as “promotion? on understory regeneration.
MethodThis study took 31 years old
L. principis-rupprechtiiplantation in Saihanba Area as the research object, we adopted the split plot design and other methods. The experiments of promotion were carried out from four aspects: stand densities, litter treatments, seed sources and seed treatments. This paper discusses the response of understory regeneration to different promotion measures.
ResultThe results showed that the regeneration can appear among the treatments and the regeneration frequency was about 100%. The ground diameter and seedling height of seedlings with different densities at the same period had little difference at the end of growth (
P> 0.05), while the ground diameter of seedlings had significant differences in two years (
P< 0.05). There was no significant difference in survival rate between different treatments (
P> 0.05), and the overall survival rate remained in the range of 43.68% 87.87%. However, the regeneration density and germination rate of seeds were significantly different among litter treatments (
P< 0.05). The regeneration density of 8 633.33 plant/ha of sulcate cleaning (SC) was the highest when artificial sowing, and seed germination rate of 1.79% was also the highest. In addition, the dynamic of regeneration changed with sowing time. When the seeds were sown naturally, the regeneration dynamics among the treatments were relatively consistent, and the peak of seedling germination was at the end of July. When the seeds were sown artificially in the middle of June, only the seeds in SC treatment germinated in large quantities at the end of July.
ConclusionThe artificial interference with litter layer and seeding are effective to promote the regeneration of
L. principis-rupprechtiiplantations. The promotion measures mainly affect the effects of regeneration by affecting the number of seedlings rather than the seedling quality. The sowing time and seed treatments affect the renewal dynamics of seedlings, and artificial sowing of untreated seeds in mid-June can cause the delay of renewal dynamics in the current years. The best way to promote the regeneration of
L. principis-rupprechtiiplantations is as follows: the first way is to sulcate clean the litter layer and spread the seeds manually before mid-June, the second way is comprehensive clean the litter layer and spread the seeds in early November of the previous year.
Abstract:
ObjectiveTo reveal the influence rule of forest type and light-felling intensity on the carbon source and sink of Korean pine forests by planting conifer and reserving broad-leaved tree (PCRBT), and to provide basis for the restoration of zonal climax vegetation broad-leaved Korean pine forest.
MethodThe annual net carbon sequestration of vegetation, net carbon emission (CH
4, CO
2) of soil heterotrophic respiration with related environmental factors(temperature, water content of soil, organic carbon, total nitrogen and so on) under different light-felling intensity(Control, Low-intensity LF-1/7, Heavy-intensity LF-1/3) were measured simultaneously by Static chamber-gas chromatograph and relative growth equation in three types of Korean pine forests by PCRB (Mongolian oak-Korean pine forest and white birch-Korean pine forest, which Korean pine planted under secondary crown for 25 ~ 35 years and light-felling for 25 ~ 30 years) in temperate in Xiaoxing’an Mountains., in order to reveal the influence of forest type and light-felling intensity on the carbon source/sink of Korean pine forest according to the net carbon balance of the ecosystem.
Results(1) The annual average efflux of soil CO
2(159.94 ~ 207.43 mg/(m
2·h)) in three forest types, were influenced by both the intensity of light-felling (heavy-intensity LF significantly increased 18.9% from Mongolian oak-Korean pine forest), and the forest type (control was white birch-Korean pine forest significantly higher than aspen-Korean pine forest and Mongolian oak-Korean pine forest, low, and heavy LF had no significant impacts among three forest types); low, and heavy LF had no significant impacts on the annual average flux of soil CH
4uptake (?.047 ~ ?.028 mg/(m
2·h)) from three forest types but white birch-Korean pine forest and aspen-Korean pine forest has significantly higher than Mongolian oak-Korean pine forest. (2) Low, and heavy-intensity LF made the annual net carbon sequestration of vegetation (1.66 ~ 3.99 t/(ha·year)) from three forest types had no significant effect, but white birch-Korean pine forest significantly higher (105.4% ~ 124.1% and 31.0% ~ 32.6%) than aspen-Korean pine forest and Mongolian oak-Korean pine forest , aspen-Korean pine forest has significantly higher(55.7% ~ 71.1%) than Mongolian oak-Korean pine forest. (3) Low-intensity LF had no significant impacts on carbon sink in Mongolian oak-Korean pine forest (?.93 ~ ?.12 t/(ha·year)) and aspen-Korean pine forest (?.65 ~ ?.03 t/(ha·year)) and White birch-Korean pine forest (?.13 ~ 0.46 t/(ha·year)), but the level and direction of the effect of heavy-intensity LF were closely related to the forest type, Mongolian oak-Korean pine forest has significantly increased about 72.3%, White birch-Korean pine forest converted into carbon source, aspen-Korean pine forest has slightly increased carbon source.
ConclusionTherefore, considering the maintenance of forest carbon sink in Korean pine forests by planting conifer and reserving broad-leaved tree, the faster recovering White birch-Korean pine forest and aspen-Korean pine forest was more appropriate to take heavy-intensity LF, while the slower recovering Mongolian oak-Korean pine forest are suitable to be low-intensity LF.
Display Method:
Abstract:
Abstract:
ObjectiveThe variation characteristics of soil nitrogen of
Pinus tabuliformisnatural secondary forest in Pingquan County, Hebei Province of northern China were analyzed in different years after fire, and the influencing factors of soil nitrogen were explored in combination with stand factors, site factors and fuel factors, so as to provide a scientific basis for nutrient circulation and vegetation restoration after fire.
MethodStudy sites were burnt areas located in Liuxi Town of Pingquan County. Soil samples were collected in 2015(the year after the fire, 0 year), 2016 (1 year after the fire, 1 year) and 2021 (6 years after the fire, 6 years), respectively. We analyzed the tendency of content of soil total nitrogen (TN), alkali-hydrolysable nitrogen (AN), ammonium nitrogen (NH
4
+-N) and nitrate nitrogen (NO
3
∑/sup>-N) under different years (0 year, 1 year and 6 years), different fire intensities (CK, control test plots which is unburnt area; L, low intensity burnt area; M, moderate intensity burnt area; H, heavy intensity burnt area), and different soil layers (0?0 cm and 10?0 cm). Correlation analysis (Pearson) and redundancy analysis (RDA) were used to explore the potential impact of stand factors (tree height, DBH, canopy density), site factors (slope position and slope gradient) and fuel factors (1 h, 10 h, 100 h fuel load, 1 h,10 h,100 h fuel water content) on soil nitrogen.
Result(1) Fire intensity, soil layer and years had significant influence on 4 types of soil nitrogen (
P< 0.05). Fire intensity and soil layer had an interaction with all kinds of soil nitrogen (
P< 0.05) in 2015. Fire intensity and years had an interaction with all kinds of soil nitrogen (
P< 0.05). Fire intensity, soil layer and years showed no three-factor interaction with all kinds of soil nitrogen (
P> 0.05). (2) Total nitrogen content, ammonium nitrogen content and nitrate nitrogen content increased in 2016 (1 year), especially in heavy intensity areas (H), and the amplification was 464.67%, 397.97%, 185.63%, respectively. But alkali-hydrolysable nitrogen content decreased in each sample plot, especially in M-plot (52.48%). Total nitrogen content, ammonium nitrogen content and alkali-hydrolase nitrogen content increased in 2021 (6 years), especially in moderate intensity areas (M), and the amplification was 368.78%, 209.00%, 427.51%, respectively. But nitrate nitrogen content decreased by 14.31% and 14.34% in low intensity areas (L) and moderate intensity areas (M), respectively. (3) RDA results showed that fuel water content had the most contribution to the change of soil nitrogen content. 1 h fuel water content had an effect on alkali-hydrolase nitrogen content. 100 h fuel water content had an effect on nitrate nitrogen content. Both of them had a positive relationship between fuel factors and soil nitrogen. Stand factors and site factors had little explanatory on soil nitrogen content, which was the indirect effect.
ConclusionThe change of soil nitrogen content decreases first and then raises up, which is the common action with fire intensity, soil and years. At the early stage after burning (2015, 0 year; 2016, 1 year), fire intensity plays a significant role in affecting soil nitrogen content. However, the influence power of fire intensity decreased in 2021 (6 years). The direct impact of fire intensity on soil nitrogen content is reduced, and the mediation between fire intensity and soil continues to affect the change of soil nitrogen content through soil moisture content, temperature, pH and other indicators. The regeneration and development of vegetation in burnt areas is also affected by mediating effects. The differences in nutrient utilization strategies at different growth stages and the accumulation of vegetation litter are also important reasons for the significant changes of soil nitrogen content in 1 year and 6 years after fire.
Abstract:
ObjectiveThe population of
Populus euphraticarecovered to a certain extent following the ecological water conveyance project, but its restoration result was far less significant than for
Tamarix ramosissima, which overlaped its ecological niche. To provide scientific reference for protecting and managing
P. euphraticaforests and developing ecological water conveyance projects in oases, this study explored whether the adaptability advantages of
P. euphraticapopulation were affected by symbiosis with
T. ramosissimain different soil water and salinity environments.
Method
P. euphraticaand
T. ramosissimaforests in the arid area in northwestern China were selected as the key constructive species of riparian forest communities, and two common soil water and salinity habitats with high and moderate soil moisture and salinity were established as a means of analysing the spatial distribution of both species and their relationships with saline water.
Result(1) In an environment with relatively high water and salt content, the
P. euphraticapopulation demonstrated a declining trend, with relatively few young woods and a limited amount of regeneration, whereas the
T. ramosissimapopulation was stable. The population structure of
P. euphraticawas found to be stable with little difference between each age class, whereas
T. ramosissimawas found to have a growing population. (2) In different salt and water environment, both species were mainly distributed in aggregation as a means of resisting the stress of an adverse environment, and
P. euphraticaseedling growth was inhibited by
T. ramosissima.(3) Different soil water and salinity environments resulted in differences in the abundance of both species. The ratio of
T. ramosissimato
P. euphraticawas found to have a positive correlation with salinity, but as the water content increased, the number of
T. ramosissimadecreased and
P. euphraticaincreased with lower salt content.
ConclusionThe results further verify that competition is an important factor for the decline of
P. euphraticaduring the succession process, with the exception of environmental filtering.
T. ramosissimawill gradually replace
P. euphraticain high-salt habitats, but the improvement of water conditions could slow down the occurrence of this trend.
Abstract:
ObjectiveThis paper aims to analyze the current and future potential distributions of four common tree species (
Pinus sylvestris,
Pinus tabuliformis,
C
aragana korshinskiiand
Larix gmeliniivar.
principis-
rupprechtii) in the Loess Plateau region of northern China, and to reveal the effects of climate change on spatial distribution patterns of plants.
MethodFour dominant species on the Loess Plateau were studied based on 19 climate factors and 5 indicators from Holdridge life zone model and Kira index system: bio-temperature (ABT), potential evapotranspiration rate (PER), warmth index (WI), coldness index (CI) and humidity index (HI). The Maxent model was used to predict the potential geographical distribution of the four tree species under current and future scenarios (2041?060, 2061?080) SSP126, SSP245 and SSP585. The Jackknife method was used to analyze the main environmental factors affecting its distribution, and the predicted results were tested by the area under receiver operating characteristic curve (AUC).
Result(1) Maxent model can well simulate the potential geographical distribution range of major established species in the Loess Plateau, and the average AUC of each species was greater than 0.8. (2) For
Pinus sylvestris,
Pinus tabuliformisand
Caragana korshinskii, both temperature and precipitation limited their distribution, while for
Larix gmeliniivar.
principis-rupprechtii, precipitation was the main factor affecting their distribution. Temperature seasonality, potential evapotranspiration rate, precipitation of the driest month and precipitation of the wettest quarter were the main environmental factors affecting the distribution of
Pinus sylvestris. Temperature annual range, temperature seasonality, minimum temperature of the coldest month, precipitation of the warmest quarter and potential evapotranspiration rate were the main factors affecting the distribution of
Pinus tabuliformis. The main factors affecting the distribution of
Caragana korshinskiiare maximum temperature of the warmest month, warmth index, isotherm, potential evapotranspiration rate and precipitation of the coldest season. The main factors affecting the distribution of
Larix gmeliniivar.
principis-rupprechtiiwere mainly related to precipitation, which were precipitation of the wettest month, precipitation of the wettest quarter, variation coefficient of precipitation, and potential evapotranspiration rate. (3) The potential suitable areas of
Pinus tabuliformis,
Caragana korshinskiiand
Larix gmeliniivar.
principis-rupprechtiiwill migrate to the northwest, while that of
Pinus sylvestriswill migrate to the southwest. The potential suitable areas of
Pinus tabuliformisand
Larix gmeliniivar.
principis-rupprechtiishowed a trend of expanding first and then decreasing, while the potential suitable areas of
Caragana korshinskiiand
Pinus sylvestriswould continue to expand, especially the proportion of highly suitable areas of
Pinus sylvestriswould expand to 50.97% in 2070s.
ConclusionClimate change will deprive
P
inus tabuliformisand
Larix gmeliniivar.
principis-rupprechtiiof some of their highly suitable areas, but at the same time, the highly suitable areas of
Caragana korshinskiiand
Pinus sylvestriswill expand significantly.
Caragana korshinskiiand
Pinus sylvestrisare preferred in the project of converting farmland to forest land on the Loess Plateau.
Abstract:
ObjectiveUsing the method of extracting vegetation phenology by remote sensing,taking Xiaoxing’an Mountains of northeastern China as the study area, this paper analyzes the temporal and spatial changing characteristics of forest vegetation phenology and the response of forest vegetation phenology change to climate change.
MethodBased on GIMMS NDVI 3g image, the forest vegetation growth curve was fitted by univariate sixth order polynomial, and the phenological parameters of forest vegetation SOS, vegetation EOS and vegetation LOS in Xiaoxing’an Mountains from 1982 to 2015 were extracted by pixel dynamic threshold method. Using ArcGIS software, the temperature, precipitation and sunshine duration data were analyzed pixel by pixel with vegetation phenological parameters to obtain partial correlation coefficients between phenological parameters and meteorological factors.
Result(1) The characters in spatial distribution of multi-year mean value of vegetation phenology showed a kind of gradual change from northwest to southeast, including the advance of vegetation SOS, the delay of vegetation EOS and the extension of vegetation LOS. (2) The SOS of forest vegetation in Xiaoxing’an Mountains was concentrated among 112.1th?28.3th day of the year, with an abrupt change around 1998. Before 1998, it showed a significant advancing trend (
R
2= 0.284,
P= 0.028), and after 1998, it showed a non-significant delaying trend (
R
2= 0.002,
P= 0.86), resulting in a non-significant change during the whole analysis period (1982?015), with a rate of change at 0.12 d per ten years (
R
2= 0.001,
P= 0.872). The forest vegetation EOS was concentrated among 277.3th?94.8th day of the year, and showed a significant delaying trend during the whole analysis period, with a rate range of 2.33 d per ten years (
R
2= 0.294,
P< 0.01). The LOS of forest vegetation was concentrated among 149.5?67.5 days, and showed a significant extension trend during the whole analysis period, with a rate of change at 2.45 d per ten years (
R
2= 0.231,
P< 0.01). (3) The forest vegetation SOS was correlated with the April temperature of current year, followed by the February temperature of current year. The vegetation EOS was correlated with the precipitation in August of current year, followed by the June temperature in current year.
Conclusion(1) The multi-year average value of forest vegetation phenology and the multi-year average value of hydrothermal conditions in Xiaoxing’an Mountains show relatively consistent spatial characteristics. (2) The change of vegetation EOS during the study period is mainly driven by the change of precipitation in August. The decline of precipitation in August is the main reason for the significant delay of vegetation EOS. (3) The stagnation of global warming at the end of the 20th century causes the temperature in February to change from a significant increase to a non-significant decrease around 1998, causing a sudden change in the trend of vegetation SOS around 1998, leading to a non-significant change in vegetation SOS during the whole period.
Abstract:
ObjectiveThis study aimed to theoretically support the scientific assessment of the carbohydrate-water coupling connection of
Cryptomeria japonica.
MethodThe water use efficiency (WUE) of
Cryptomeria japonicawas calculated using the tree-ring stable carbon isotope method in this study. Additionally, average temperatures (
T), precipitation (
W), average wind speeds (Ws), solar radiation (Rs), the drought index (SPEI, SPI, WI), and other climate change-related indicators were used to analyze the WUE of
Cryptomeria japonicaand its adaptation to climate change.
Result(1) From 1969 to 2018, the sequence of
13C values of
Cryptomeria japonicatree rings in Lushan Mountain, Jiangxi Province of eastern China showed a downward trend; the variation range was ?3.09 to ?5.67? and the annual average was ?4.55? the inter-annual value of
Cryptomeria japonicaWUE showed an upward trend; the variation range was 91.06 to 118.89 μmol/mol, with an annual average of 102.37 μmol/mol. (2) Correlation analysis revealed that the WUE of
Cryptomeria japonicain Lushan Mountain was significantly correlated with the temperature in July, September to November of the previous year, February to June, and September to November of the current year, and significantly negatively correlated with the wind speed in July to December of the previous year and January to December of the current year. However, the solar radiation, precipitation, SPEI, WI, and SPI of each month had no significant impact on the WUE of
Cryptomeria japonicaon Lushan Mountain. (3)The multiple regression model analysis showed that the WUE of
Cryptomeria japonicaon Lushan Mountain was mainly related to Ws
1(wind speed in January of the current year),
T
3(average temperature in March of the current year),
T
9(average temperature in September of the current year),
T
?(average temperature in September of the previous year), and Ws
12(wind speed in December of the current year).
Conclusion
Tand Ws are the primary climatic variables affecting WUE of
Cryptomeria japonica. The WUE of
Cryptomeria japonicaon Lushan Mountain is not significantly affected by
W, Rs, or the drought indicators (SPI, SPEI and WI).
Abstract:
ObjectiveThis paper aims to investigate the important founction of CaM-like proteins in Chinese jujube in resistance to cold stress and identify the key
ZjCML, which could provide theoretical basis for cold breeding in Chinese jujube by using them.
MethodThrough using bioinformatics technology, the number and related structural information of
CMLin Chinese jujube were analyzed comprehensively in the current study. And then, we used RNA-seq and real-time fluorescence quantitative PCR technology to analyze its expression pattern in response to low temperature stress, laying a foundation for screening key cold resistance genes.
ResultA total of 23
ZjCMLgenes were identified in Chinese jujube genome. All of them distributed unevenly on 12 chromosomes. In addition,
ZjCMLcan be divided into 12 subgroups, and protein interaction network prediction showed that 16 ZjCML existed in the network and they had mutual interaction relationships. Moreover, RNA-seq analysis showed that the expression patterns of
ZjCML13 and
ZjCML6 in response to cold stress between ‘Dongzao and its autotetraploids were significantly different. The expression level of
ZjCML13 in response to cold stress in ‘Dongzao was significantly higher than that in its autotetraploid at 6 and 24 h. External CaCl
2and melatonin treatments could significantly induce the expression of
ZjCML13 in autotetraploids ‘Dongzao under cold stress at 6 and 24 h, indicating that it may regulate cold resistance of autotetraploid ‘Dongzao by inducing the expression of
ZjCML13.
ConclusionThe
ZjCMLgene family have specific characteristics and expression patterns,
ZjCML13 might play important role in regulation of cold difference between ‘Dongzao and its autotetraploids.
Abstract:
ObjectiveThis paper aims to research the coupling effects of furrow irrigation and nitrogen fertigation on the growth and stand productivity of high-density and short-rotation triploid
Populus tomentosaS86 pulp plantations, in order to provide scientific theoretical basis for selecting efficient furrow irrigation-fertilization technology system suitable for the local area.
MethodThe plant materials were triploid
P. tomentosaS86 in Gaotang County, Shandong Province of eastern China. A completely random block experiment design was adopted to monitor three irrigation levels, i.e. irrigation started when the soil water potential reached ?0 kPa (W1), ?3 kPa (W2) and ?5 kPa (W3), and four fertigation levels (N1, 120 kg/(ha·year); N2, 190 kg/(ha·year); N3, 260 kg/(ha·year); N4, 0 kg/(ha·year)), and the control treatment was with no irrigation and no fertigation set (CK).
ResultIt took a long time for the fast-growing period of DBH growth of triploid
P. tomentosaS86. The DBH growth of different stand ages in the growing season conformed to the Logistic function (
R
2> 0.99), and the difference of furrow irrigation and fertilization treatments was mainly manifested in June. Nitrogen application in furrow irrigation significantly affected the DBH increment and relative growth rate of 2-year-old
P
. tomentosaS86 plantations (
P< 0.05), but had no significant effect on 3?-year-old
P. tomentosaS86 plantations. The coupling measures of water and fertilizer had a strong promotion effect on the average volume and average productivity of 2?-year-old trees, but had no significant promotion effect on 4?-year-old
P
. tomentosaS86 plantations. The average annual productivity of triploid
P. tomentosaS86 stands was 19.65?5.31 m
3/(ha·year) in four years, among which, W1N1 had the highest annual productivity, which was significantly higher than CK by 28.41% (
P< 0.05). Under the treatment of 5-year-old stand W1N1, the tree growth was optimal, with unit area volume and average productivity reaching 104.39 m
3/ha and 27.42 m
3/(ha · year), respectively, which were 28.15% and 11.74% higher than CK treatment, respectively.
ConclusionThe furrow irrigation and fertilizer coupling measures have different degrees of improvement on the unit area storage and annual productivity of 2?-year-old triploid
P. tomentosaS86
stand, but have no significant effect on the unit area storage and annual productivity of 4?-year-old
P. tomentosaS86 plantation. Among them, W1N1 furrow irrigation and nitrogen application treatment has the best growth. Under similar climatic and soil conditions, maintaining sufficient water (irrigation threshold of ?0 kPa) and a lower nitrogen application rate (120 kg/(ha · year) is most conducive to the growth of high-density short-rotation triploid
P
. tomentosatargeting pulp forests.
Abstract:
ObjectiveThe
Parashorea chinensisis an endemic and endangered species in China, and it is classified as a class protected wild plant. Plantation cultivation is an important means to expand its populations. Phosphorus (P) supply is a major influence on tree growth and development, and P dissolving bacteria plays an important role in P transformation. This research aimed to screen high-efficient phosphate-solubilizing bacteria (PSB) from the rhizosphere soil of
P. chinensisplantations of different ages, and explore its P-solubilizing characteristics, so as to provide bacterial resources and culture conditions for the development of microbial fertilizer suitable of
P. chinensis.
Method(1) PSB was isolated and screened from the rhizosphere soil of
P. chinensisin different ages by inorganic P solid medium. The physiological and biochemical tests and 16S rDNA gene sequence were used to further identify 4 strains of PSB. (2) The relationship between the amount of P dissolved by PSB and the pH of the bacterial solution was studied by detecting the dynamics of P solubilization. (3) A single factor experiment was conducted to investigate the P-solubilizing characteristics of high efficiency PSB under different environmental and nutritional factors.
Result(1) A total of 18 strains of phosphorus solubilizing bacteria were isolated and screened, and the 4 strains with the strongest P-solubilizing capacity were P4, P8, P12 and P30 (P-solubilizing capacity was 552.87, 559.78, 548.53 and 598.89 mg/L, respectively). (2) Strain P8 was identified as
Burkholderia gladioli, P4 and P12 as
Burkholderia cepacia, and P30 as
Bacillus cereusby physiological, biochemical identification and combined with phylogenetic tree analysis. (3) There was a highly significant (
P< 0.01) negative correlation between the pH of the cultures and the amount of phosphorus dissolved by the P4, P8, P12 and P30 strains, with correlation coefficients of ?.995, ?.990, ?.985 and ?.997, respectively. (4) The results of single factor test showed that the PSBs had the preferable P-solubilizing effects at a temperature of 30?5 ? the pH of 5.5?.5, the NaCl mass fraction was 0?.5%, the carbon (C) sources were sucrose, lactose and glucose, and the nitrogen (N) sources were ammonium oxalate and ammonium sulfate. The optimal C∶N of strain P30, P12 and P4 was 20?, and that of P8 was 40?. The optimal P source for strain P12 was FePO
4, and Ca
3(PO
4)
2for P30, P8 and P4.
ConclusionThe P-solubilizing ability of PSBs can be significantly affected under different culture conditions. The 4 strains of high efficiency PSB have preferable P-solubilizing ability, which can dissolve a variety of insoluble inorganic phosphates. Therefore, it is expected to provide germplasm resources for the development of high-efficiency microbial phosphate fertilizers with a good application potential.
2023, 45(3): 93-103.
doi:10.12171/j.1000-1522.20220028
Abstract:
ObjectiveIn this paper, the host preference and selectivity of
Perina nudato different
Ficusspecies were investigated to provide scientific basis for the control of
Perina nuda.
Method4 species of host trees (
Ficus macrocarpa,
F. altissima,
F. benjaminaand
F. concinna) in Guangzhou City, Guangdong Province of southern China were selected to feed
P. nudaand the growth, development and feeding amount of
P. nudaafter feeding on different leaves of banyan were analyzed.
ResultThere were differences in the larval instars of
P. nudareared by different banyan trees. During larval instar,
P. nudafed on
F.
microcarpawas 5th to 7th instar, that fed on
F. altissima,
F. concinnaand
F. benjaminawere 6th to 8th instar. The development period of larval of
P. nudafed on
F. benjaminawas longest while the shortest period was the
P. nudafed on
F. microcarpa. Additionally, body length, body mass and fecal mass of
P. nudalarval fed on
F.
microcarpawere at the top among 4 banyan species. In the meanwhile, the 2nd to 7th instar larvae reared by
F. microcarpahad the widest head capsule (the 1st instar larvae fed on
F. altissimahad the widest head capsule). Besides, the survival rates of
P. nudalarvae reared by
F.
microcarpaand
F. altissimawere significantly higher than those of
F. benjaminaand
F. concinna. Furthermore, the female adults of
P. nudalarvae feeding on the
F.
microcarpahad the longest lifespan, while the male adults feeding on
F. altissimahad the longest lifespan. It was also showed that the female adult had the shortest pre-ovulation period, and the single female laid the most eggs. Finally, it was found that the larvae fed on
F.
microcarpaat the 1st to 4th instars preferred to feed on
F. altissimaat the 5th instar, while the host preferences of 5th instar
P. nudalarvae fed on other three banyan species were not obvious.
ConclusionThere are significant differences in the preference and selectivity of
P. nudato the four banyan species.
F. microcarpaand
F. altissimaare more suitable for the growth and development of
P. nudathan
F. benjaminaand
F. concinna.
2023, 45(3): 104-112.
doi:10.12171/j.1000-1522.20210254
Abstract:
ObjectiveThis paper aims to select Asiatic lilies with strong resistance to
Botrytis elliptica, the resistance of some Tiger and Pearl series Asian lilies and
Lilium davidiivar.
unicolorto
B. ellipticawas evaluated, and the physiological mechanism of resistance was preliminarily explored.
MethodThe disease resistance of different cultivars or species was evaluated by ex vivo leaf inoculation. On this basis, the physiological changes of selected disease-resistant and susceptible cultivars after inoculation were determined.
ResultThe comprehensive evaluation results showed that: (1) the resistance of Tiger, Pearl lilies and
L. davidiivar.
unicolorto
B. ellipticawas different. Relatively strong resistance to
B. ellipticawas ‘Pearl Melanie? which belonged to the medium resistance level. The weakest resistance materials were ‘Pearl Justin?
L. davidiivar.
unicolor, ‘Pearl White and ‘White Twinkle? (2) There was no significant correlation between resistance level and stomatal density, stomatal size. (3) The physiological responses of the resistant cultivar ‘Pearl Melanie and susceptible cultivar ‘Pearl Justin were obviously different after inoculation. The content of MDA showed an increasing trend with the extension of inoculation time, while the activities of oxalate oxidase and chitinase gradually increased, and the activities of β-1,3-glucanase decreased with time. The MDA content of the resistant cultivars was relatively lower than susceptible cultivar, and the activities of oxalate oxidase and chitinase were higher than susceptible cultivar.
ConclusionThere is no significant correlation between stomatal characteristics and disease resistance, the physiological mechanism of lillies with distinct disease resistance is different. During the physiological response, MDA content, oxalate oxidase activity and chitinase activity can be used as evaluation indexes for evaluating Asiatic lilies for resistance to
B. elliptica.
Abstract:
ObjectiveGreenspace is the ecological foundation of urban and rural development, and a good greenspace system is an important guarantee for coordinating urban development and nature conservation. Comprehensive measurement and investigation of the spatio-temporal evolution pattern of city-wide greenspace in the lower reaches of the Yellow River can help the planning for the construction of ecological corridors in the lower reaches and ecological improvement in the floodplain.
MethodFour cities in the lower reaches of the Yellow River, Jinan, Heze, Zhengzhou, and Xinxiang, were used as the study objects, and year 1990, 2000, 2010, and 2020 were taken as the time nodes. Using vegetation cover density and the secondary classification of land use, the city-wide green space types were classified, and then the transfer matrix, landscape pattern indices, urban-to-rural trajectory and geo-detector were used to conduct quantitative research on the spatio-temporal patterns and mechanism of city-wide evolution greenspace.
Result(1) In the past 30 years, the greenspace had transferred 3 223 km
2to the bare surface, and the bare surface had transferred 181 km
2to all kinds of greenspace; 735 km
2of greenspace was transferred to each other, of which 466 km
2was transferred from higher density to lower density greenspace, and 269 km
2was transferred from lower density to higher density greenspace. (2) The decrease of percentage of landscape (PLAND) and area-weighted mean shape index (AWMSI) of sparse greenspace, the decrease of number of patches (NP) of all kinds of greenspace, and the increase of mean patch size (MPS) and functional connectivity (PC) were the general rules of landscape pattern indices. (3) On the urban-rural gradient, the peaks and valleys of low density greenspaces moved significantly, while high and medium density greenspaces were relatively fixed. (4) The influence of natural environmental factors on the geographical distribution of greenspace in Jinan, Shandong Province of eastern China, Zhengzhou and Xinxiang, Henan Province of central China was dominant, and the cumulative influence of socio-economic factors in each city increased by 3.1%?.4%, showing an increasingly obvious non-linear enhancement with natural environmental factors. influence of socio-economic factors in each city increased by 3.1%?.4%, showing an increasingly obvious non-linear enhancement with natural environmental factors.
ConclusionDuring the 30 years, the total amount of regional greenspace is lost, and the internal transfer of greenspace is mainly from higher density to lower density, with more transfers along the edges of built-up areas and along the wide floodplain; the overall trend of landscape pattern changes from obvious fluctuation to nearly stable, from fragmentation and dispersion to integration and connectivity, and the improvement trend is more obvious in regional central cities; the urban-to-rural trajectory characteristics differ greatly between cities and greenspace types; the synergistic effect among influencing factors is gradually increasing, and greenspace gradually becomes the result of natural-social interconfiguration. In the future, the city-wide greenspace should be transformed from a “barrier to a “hub according to the needs of the city.
2023, 45(3): 127-136.
doi:10.12171/j.1000-1522.20220360
Abstract:
ObjectiveThis paper aims to further improve the high value-added utilization of culm resources of
Chimonobambusa utilis, the chemical components, physical and mechanical properties were investigated, and the variation regularity with age and axial part of bamboo culm were also revealed.
MethodIn this study, the natural plants of
Chimonobambusa utiliswere used as raw materials to determine the chemical component (mass fraction in this article) content and physical and mechanical properties, such as density, dry shrinkage, compressive strength parallel to grain, modulus of rapture (MOR), modulus of elasticity (MOE) and hardness according to the national standards. The crystallinity of cellulose and microfibril angle was calculated from the results of X-ray diffraction.
ResultThe content of each chemical component of
Chimonobambusa utilisvaried slightly with the age and axial part, and the variation pattern was not significant. The crystallinity increased with the age of bamboo and then decreased gradually, with a maximum of 50.39% at 2 years old, and increased gradually with the increase of axial part. The microfibril angle decreased and then increased with increasing age and axial part, and the smallest angle was 9.10° in the middle of 2 years old. The basic density ranged from 0.513 to 0.693 g/cm
3, the oven-dried density ranged from 0.535 to 0.725 g/cm
3, and the air-dried density ranged from 0.556 to 0.756 g/cm
3. All densities showed an increasing trend with increasing age and axial part, and increased significantly between 1 and 2 years, and then increased steadily to stabilize. The oven-dried and air-dried shrinking ratio showed a decreasing trend with the increasing age and axial part, and decreased significantly between 1? years, and then decreased steadily, the latter fluctuating relatively more. The compressive strength parallel to grain ranged from 50.73 to 64.58 MPa, MOR ranged from 114.09 to 134.26 MPa, and MOE ranged from 8.45 to 12.42 GPa, all of which showed an increasing-decreasing-increasing trend with increasing age, and an increasing trend with increasing axial part; the mean values of inner and outer hardness ranged from 60.00 to 72.70 HD, which showed an increasing trend with increasing age and axial part. The dry shrinkage, compressive strength parallel to grain, MOE and hardness of
Chimonobambusa utiliswere significantly affected by anatomical index and major chemical components.
ConclusionBoth bamboo age and axial part of culm affected the basic properties, but the effect of bamboo age was more significant. The culm material of
Chimonobambusa utiliswas basically mature over 2 years old, which could be the optimized cutting age of
Chimonobambusa utilis. In addition, there were some significant correlations between physical-mechanical properties and anatomical structure index.
2023, 45(3): 137-144.
doi:10.12171/j.1000-1522.20220432
Abstract:
ObjectiveIn order to enrich the color system of wood products, this paper discusses the construction and color performance of SiO
2photonic crystals on the surface of wood.
MethodIn this paper, SiO
2microspheres with different particle diameters were prepared by the Stöber method, and the SiO
2photonic crystal structure color was constructed on the wood substrate by the gravity deposition self-assembly method. The chemical composition and structure of SiO
2microspheres were characterized by X-ray diffraction and Fourier transform infrared spectroscopy. The morphology of the microspheres and their arrangement on the wood substrate were characterized by scanning electron microscopy, and the particle diameter distribution of the microspheres under different treatment processes was analyzed. The color parameters and UV-visible reflectance of SiO
2structure on the wood surface were analyzed by digital camera and UV-visible absorption spectrometer.
ResultX-ray diffraction, Fourier transform infrared spectroscopy confirmed that the reaction products prepared in this paper were pure amorphous SiO
2, suitable for constructing well-colored structural color coating. The preparation formula only controlled the amount of ethanol added, and the addition amount was 80, 85, 90, 95, 100, and 105 mL, respectively. The monodisperse nano-SiO
2was generated, and their particle diameters were 294, 246, 226, 214, 194, and 181 nm, respectively. As the particle diameter of SiO
2involved in self-assembly decreased in turn, the color of the film gradually changed from red to green, blue-green, and finally to deep purple, purple, and lavender. The ultraviolet reflection wavelength gradually decreased and the color blue shifted. The SiO
2microspheres showed a three-dimensional ordered face-centered cubic structure on the surface of the wood substrate. Due to environmental disturbances, assembly defects such as cracks and missing will occur, but will not affect the overall color.
ConclusionOnly by controlling the amount of ethanol added, six different particle diameters of nano-SiO
2particles suitable for constructing photonic crystal structure color can be prepared. Silica microspheres of various particle diameters formed bright structural colors after self-assembly on the wood substrate, and the color of the structural color coating would blue shift due to the particle diameter reduction of the self-assembled microspheres. The above research content provides a simple and novel method for the large-scale preparation of wood surface structural color coatings, which can enrich the color system of wood products.
2023, 45(3): 145-152.
doi:10.12171/j.1000-1522.20220471
Abstract:
ObjectiveThis study aimed to analyze the main chemical constituents and environmental influencing factors of cork from
Quercus variabilisthrough a wide range of samples in China, which would be helpful to provide scientific reference for the oriented selection and scientific utilization of cork resources.
MethodCork from
Q. variabiliswas collected from 12 regions in China for the determination of cork resin, lignin and other major chemical components, and the chemical components of cork from different locations were compared by LSD multiple comparison, principal component analysis and cluster analysis.
ResultThe average contents of main chemical constituents (the chemical composition content in this paper refers to the mass fraction) of the cork were: the total extractable matter was (13.94 ± 0.54)%, the suberin was (41.63 ± 1.44)% and the lignin was (23.03 ± 2.26)%. According to the content of suberin and lignin, the 12 provenances could be clustered into three groups, among which Lincheng (Hebei Province of northern China), Yongxiu (Jiangxi Province of eastern China), Jinzhai (Anhui Province of eastern China), Nanjing (Jiangsu Province of eastern China) and Neixiang (Henan Province of central China) had relatively high suberin content, while Jiyuan (Henan Province of central China), Meixian (Shaanxi Province of northwestern China) and Tianshui (Gansu Province of northwestern China) belong to the groups with high lignin content. The left provenances, Shangluo (Shaanxi Province of northwestern China), Chengbu (Hunan Province of southern China), Pinggu (Beijing of northern China) and Tianlin (Guangxi of southern China) belong to the middle group. The correlation analysis showed that the content of dichloromethane extract and total extractable matter was negatively correlated with latitude, while the suberin content increased with longitude and soil nitrogen content. The annual mean temperature had little effect on chemical composition content, but mean annual precipitation had significant positive correlation with the suberin, the dichloromethane extract and total extractable content.
ConclusionOn the whole, there are certain geographical differences in the chemical composition content of cork from
Quercus variabilisin China, and they are mainly affected by latitude, mean annual precipitation, and soil nitrogen content.
2023, 45(3): 153-159.
doi:10.12171/j.1000-1522.20220345
Abstract:
ObjectiveIn order to reduce the influence of human factors on the log sizing results and improve the work efficiency, a log sizing method based on mask region instance segmentation model and edge fitting algorithm was proposed.
MethodThe method used monocular camera as the acquisition equipment, and the end face images of eucalyptus with three different diameter classes and rectangular scaleplate were taken as the research objects. Firstly, the image was collected at different distances to make a data set, and the training set, verification set and test set were divided at the ratio of 8??, and the log end face recognition experiment database was established. Secondly, the instance segmentation model was used to extract the end face part to generate the mask, the edge fitting algorithm was used to obtain the pixel size of the rectangular scaleplate and the log end face, combined the actual size of the scaleplate to obtain the actual size of the log end face. Finally, the error of fitting size of the algorithm and the error of different national standard volume calculation formulas were compared.
ResultIt was found that the example segmentation model in this paper can achieve more accurate mask segmentation of log end face, and the accuracy and recall rate were 99.89% and 99.41%, respectively. Compared with the one-stage algorithm, F1 scores and mean average precision were significantly improved. By fitting the end face to an ellipse using a least square edge fitting algorithm, the short diameter of the ellipse was obtained as the log diameter. Compared with the real value, the average percentage error was about ?.00%, which was slightly smaller than the real value. Comparing the error of logs with different sizes, the measurement error of 100% small size logs, 98% medium size logs and 95% large size logs was ?%?%. By comparing the log end face images collected at different distances, it was found that the best effect was to collect images within 50?00 cm, the average relative error didn’t exceed ?.22%, and the error gradually increased when the distance was greater than 100 cm. By comparing the calculation standards of log volume in different countries, the volume error was ?.5% according to the calculation formula of wood volume in China, which was the lowest among the four national standards of China, America, Russia and Japan.
ConclusionCompared with manual measuring, the measuring method proposed in this paper is more efficient, less affected by human factors, and can more accurately measure the log size, and achieve the goal of replacing manual log sizing operations.
Establishment Time:1979
CN?11-1932/S
ISSN?1000-1522
Supervisor:Sinopec Research Institute of Petroleum Engineering
Sponsors by:
