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RSS2017 Vol. 39, No. 11
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Abstract:
In the study, a homolous gene encoding RIN4 protein was cloned fromPopulus euphratica. To clarify the role of PeRIN4 in salinity stress,PeRIN4 was introduced toArabidopsis thalianaand plant response to NaCl was examined in transgenic plants. Salt-resistant phenotypes, activity of plasma membrane (PM) H+-ATPase and flux profiles of H+, Na+, K+were screened in this work. Subcellular localization of PeRIN4 was determined by transforming the fusion protein of pGreen0029-PeRIN4-GFP into arabidopsis mesophyll protoplast. Results showed that PeRIN4 was localized in the cytoplasm. Seven-day-old seedlings of wild-type (WT), vector control (VC) andPeRIN4-transgenic arabidopsis were exposed to 100 mmol/L NaCl saline.PeRIN4-transgenic lines showed higher survival rates and root length than WT and VC plants. These results indicated that over-expression ofPeRIN4 improved salt tolerance in arabidopsis. In addition,PeRIN4-transgenic arabidopsis exhibited a greater hydrolytic activity of PM H+-ATPase compared with WT and VC. Moreover,PeRIN4-transgenic roots showed a higher H+and Na+efflux than WT and VC, but displayed a less K+loss under salinity conditions. We concluded that PeRIN4 could improve the activity of PM H+-ATPase under salinity environment. Under NaCl stress, the activated PM H+-ATPase could sustain an H+gradient to drive the Na+/H+antiport across the PM, thus enhancing Na+exclusion, and preserve a less-depolarized membrane potential, thus restricting the K+efflux through depolarization-activated outward rectifying K+channels and non-selective cation channels. Our data demonstrate that PeRIN4 may improve salt adaptation in transgenic arabidopsis through controlling K+/Na+homeostasis under salinity environment.
In the study, a homolous gene encoding RIN4 protein was cloned fromPopulus euphratica. To clarify the role of PeRIN4 in salinity stress,PeRIN4 was introduced toArabidopsis thalianaand plant response to NaCl was examined in transgenic plants. Salt-resistant phenotypes, activity of plasma membrane (PM) H+-ATPase and flux profiles of H+, Na+, K+were screened in this work. Subcellular localization of PeRIN4 was determined by transforming the fusion protein of pGreen0029-PeRIN4-GFP into arabidopsis mesophyll protoplast. Results showed that PeRIN4 was localized in the cytoplasm. Seven-day-old seedlings of wild-type (WT), vector control (VC) andPeRIN4-transgenic arabidopsis were exposed to 100 mmol/L NaCl saline.PeRIN4-transgenic lines showed higher survival rates and root length than WT and VC plants. These results indicated that over-expression ofPeRIN4 improved salt tolerance in arabidopsis. In addition,PeRIN4-transgenic arabidopsis exhibited a greater hydrolytic activity of PM H+-ATPase compared with WT and VC. Moreover,PeRIN4-transgenic roots showed a higher H+and Na+efflux than WT and VC, but displayed a less K+loss under salinity conditions. We concluded that PeRIN4 could improve the activity of PM H+-ATPase under salinity environment. Under NaCl stress, the activated PM H+-ATPase could sustain an H+gradient to drive the Na+/H+antiport across the PM, thus enhancing Na+exclusion, and preserve a less-depolarized membrane potential, thus restricting the K+efflux through depolarization-activated outward rectifying K+channels and non-selective cation channels. Our data demonstrate that PeRIN4 may improve salt adaptation in transgenic arabidopsis through controlling K+/Na+homeostasis under salinity environment.
Abstract:
Mangrove coast is a special type of biological coast and it provides a variety of ecosystem services. To understand the evolution of the habitat of mangrove wetland, sediment cores along a hydrodynamic gradient in the inner and outer gulf of Yingluo Bay, the grain size characteristics (average grain size, sorting coefficient, skewness and kurtosis) of the sediments in the horizontal and vertical directions were analyzed using the moment method. The results showed that the sediments were mainly composed of silt and sand components, the surface samples of mangrove zone showed a trend of refinement with the maturation and deposition process of mangrove forests. The grain size distribution curve showed that the outer mangrove was more affected by hydrodynamic conditions than inner mangrove. The deposition processes of inner zone and outer zone were similar. The inner deposition was complicated by the influence of hydrodynamic conditions and biological processes. However, the sedimentary environment of the pure stand ofAvicennia marinawas relatively stable.Grain size parameters were affected by the hydrodynamic conditions and biogeography processes, and spatial heterogeneity was significant. In horizontal direction, the average particle size of the inner sample line of the bay turned to be small (texture coarsening) from inside to outside. The average particle size of the outer samples showed no obvious trends but become finer in intermediate zone distributed withRhizophora stylosatrees. The sediment segregation was poor to worse, the frequency curve was negative biased to positive bias, and the peak presented from flat to sharp distribution. In vertical direction, the average particle size decreased from the surface to deeper layer, the separation became worse, the skewness increased, and the peak state increased too, reflecting the deposition process of the forest understory environment.The correlation analysis showed that the grain size parameters of the sediments were related to different volume levels, the average grain size and kurtosis parameters were positively correlated with the content of clay and grains, and negatively correlated with the sand content, the separation coefficient and skewness were negatively correlated with the fine particulate matter content. The average grain size was positively correlated with the kurtosis, but negatively correlated with the sorting coefficient and the skewness. The separation coefficient was negatively correlated with the kurtosis, and the skewness was negatively correlated with the kurtosis. A variety of roles were involved in the formation of sediment, and mangrove forests changed the hydrodynamic conditions of the coast, which affected the deposition process in turn. The results are significant to understand the biomechanical processes of mangrove wetlands on a century scale.
Mangrove coast is a special type of biological coast and it provides a variety of ecosystem services. To understand the evolution of the habitat of mangrove wetland, sediment cores along a hydrodynamic gradient in the inner and outer gulf of Yingluo Bay, the grain size characteristics (average grain size, sorting coefficient, skewness and kurtosis) of the sediments in the horizontal and vertical directions were analyzed using the moment method. The results showed that the sediments were mainly composed of silt and sand components, the surface samples of mangrove zone showed a trend of refinement with the maturation and deposition process of mangrove forests. The grain size distribution curve showed that the outer mangrove was more affected by hydrodynamic conditions than inner mangrove. The deposition processes of inner zone and outer zone were similar. The inner deposition was complicated by the influence of hydrodynamic conditions and biological processes. However, the sedimentary environment of the pure stand ofAvicennia marinawas relatively stable.Grain size parameters were affected by the hydrodynamic conditions and biogeography processes, and spatial heterogeneity was significant. In horizontal direction, the average particle size of the inner sample line of the bay turned to be small (texture coarsening) from inside to outside. The average particle size of the outer samples showed no obvious trends but become finer in intermediate zone distributed withRhizophora stylosatrees. The sediment segregation was poor to worse, the frequency curve was negative biased to positive bias, and the peak presented from flat to sharp distribution. In vertical direction, the average particle size decreased from the surface to deeper layer, the separation became worse, the skewness increased, and the peak state increased too, reflecting the deposition process of the forest understory environment.The correlation analysis showed that the grain size parameters of the sediments were related to different volume levels, the average grain size and kurtosis parameters were positively correlated with the content of clay and grains, and negatively correlated with the sand content, the separation coefficient and skewness were negatively correlated with the fine particulate matter content. The average grain size was positively correlated with the kurtosis, but negatively correlated with the sorting coefficient and the skewness. The separation coefficient was negatively correlated with the kurtosis, and the skewness was negatively correlated with the kurtosis. A variety of roles were involved in the formation of sediment, and mangrove forests changed the hydrodynamic conditions of the coast, which affected the deposition process in turn. The results are significant to understand the biomechanical processes of mangrove wetlands on a century scale.
2017, 39(11): 18-27.
doi:10.13332/j.1000-1522.20170146
Abstract:
By applying different concentrations of exogenous oxalic acid or citric acid solutions, the effects of organic acids on some physiological and biochemical parameters, element absorption and growth of Pb-stressedLarix olgensisseedlings for different treatment times were studied, especially the effects on chlorophyll fluorescence, root morphology and nutrient absorption. The results showed that, Pb treatment had stressful effects on the seedlings, lipid peroxidation andF0in leaves significantly increased, soluble protein contents, chlorophyll fluorescence (Fm,Fv,Fv/FmandFv/F0) in leaves, root surfarea, length, volume and specific root length all decreased. K, Ca, Fe and Pb contents in fine roots and leaves, and Mg contents in fine roots obviously increased, but Mg contents in leaves decreased, and biomass of root, stem and leaf all significantly decreased. The harmful effects were promoted with increasing Pb treatment times. When Pb-stressed plants were exposed to oxalic acid or citric acid, the physiological and root morphological parameters were reversed, and biomass of root, stem and leaf all significantly increased, so exogenous organic acids can improve the tolerance ofL.olgensisseedlings to Pb stress. As to the effects of organic acids on the characteristics shown above, the desirable treatment of organic acid was 5.0 or 10.0 mmol/L for 20 or 30 days, and citric acid was more effective than oxalic acid. Oxalic acid or citric acid decreased the contents of Mg, K, Ca in fine roots and leaves, however, Fe contents in fine roots and leaves significantly increased. Under lower concentrations of organic acid treatments, Pb contents inL.olgensisfine roots and leaves decreased, at this time the detoxification mechanism of the seedlings to Pb stress was mainly the external rejection mechanism, however, Pb contents increased under higher concentrations (5.0-10.0 mmol/L), here internal resistance mechanism was dominant, and it's also possible that two mechanisms work together. The study can theoretically guide phytoremediation of Pb-stressed soils with organic acid andL.olgensisseedling amendments, and as well as open up new ideas to the effective utilization of the Pb-stressed soil in northeastern China.
By applying different concentrations of exogenous oxalic acid or citric acid solutions, the effects of organic acids on some physiological and biochemical parameters, element absorption and growth of Pb-stressedLarix olgensisseedlings for different treatment times were studied, especially the effects on chlorophyll fluorescence, root morphology and nutrient absorption. The results showed that, Pb treatment had stressful effects on the seedlings, lipid peroxidation andF0in leaves significantly increased, soluble protein contents, chlorophyll fluorescence (Fm,Fv,Fv/FmandFv/F0) in leaves, root surfarea, length, volume and specific root length all decreased. K, Ca, Fe and Pb contents in fine roots and leaves, and Mg contents in fine roots obviously increased, but Mg contents in leaves decreased, and biomass of root, stem and leaf all significantly decreased. The harmful effects were promoted with increasing Pb treatment times. When Pb-stressed plants were exposed to oxalic acid or citric acid, the physiological and root morphological parameters were reversed, and biomass of root, stem and leaf all significantly increased, so exogenous organic acids can improve the tolerance ofL.olgensisseedlings to Pb stress. As to the effects of organic acids on the characteristics shown above, the desirable treatment of organic acid was 5.0 or 10.0 mmol/L for 20 or 30 days, and citric acid was more effective than oxalic acid. Oxalic acid or citric acid decreased the contents of Mg, K, Ca in fine roots and leaves, however, Fe contents in fine roots and leaves significantly increased. Under lower concentrations of organic acid treatments, Pb contents inL.olgensisfine roots and leaves decreased, at this time the detoxification mechanism of the seedlings to Pb stress was mainly the external rejection mechanism, however, Pb contents increased under higher concentrations (5.0-10.0 mmol/L), here internal resistance mechanism was dominant, and it's also possible that two mechanisms work together. The study can theoretically guide phytoremediation of Pb-stressed soils with organic acid andL.olgensisseedling amendments, and as well as open up new ideas to the effective utilization of the Pb-stressed soil in northeastern China.
Abstract:
Genetic improvement of Chinese pine in Zhongwan Improved Variety Base, Gansu Province of northwestern China, is in the key transition period from the first breeding cycle to the second breeding cycle. How to effectively select and utilize germplasm resources of the second breeding cycle, based on the previous improvement results and combined modern theories and technologies in tree breeding, has become important issues to be addressed immediately. Using large-scale no-peditree open-pollinated bulked progeny population from the first-generation seed orchard of Chinese pine in Zhongwan Improved Variety Base, Gansu Province, as study materials, this study elaborates issues about open-pollinated bulked progenies based elite germplasm resource selection, evaluation and utilization strategies for advanced cycle improvement of Chinese pine. Results showed that 40 superior individuals were selected based on the relative growth of stem volume, with the mean volume dominance ratio of 0.83. Population consisting 40 individuals had high levels of genetic diversity, with the mean polymorphism information content of 0.620 2. Results from SSR molecular markers based phylogenetic analysis showed that the 40 individuals had varying phylogenetic relationships, belonged to 23 homogenous groups. To effectively control inbreeding, the 40 individuals were conducted within-homogenous group selection and finally only 23 superior individuals were remained and used for parents of seed orchard in the second breeding cycle. Combined with the results of volume dominance ratios and phylogenetic analysis of these parents, seed orchard in the second breeding cycle of Zhongwan Improved Variety Base was suggested to adopt the grouped, unbalanced, complete, fixed block design, which had taken the increase of volume genetic gain and the maintenance of genetic diversity of seed orchrd progenies into consideration simultaneously. Results from this study will provide new insights into effective selection and rational utilization of elite germplasm resources in advanced breeding cycles of Chinese pine, and will lay the foundation for shortening breeding cycle and increasing breeding efficiency in genetic improvement of Chinese pine.
Genetic improvement of Chinese pine in Zhongwan Improved Variety Base, Gansu Province of northwestern China, is in the key transition period from the first breeding cycle to the second breeding cycle. How to effectively select and utilize germplasm resources of the second breeding cycle, based on the previous improvement results and combined modern theories and technologies in tree breeding, has become important issues to be addressed immediately. Using large-scale no-peditree open-pollinated bulked progeny population from the first-generation seed orchard of Chinese pine in Zhongwan Improved Variety Base, Gansu Province, as study materials, this study elaborates issues about open-pollinated bulked progenies based elite germplasm resource selection, evaluation and utilization strategies for advanced cycle improvement of Chinese pine. Results showed that 40 superior individuals were selected based on the relative growth of stem volume, with the mean volume dominance ratio of 0.83. Population consisting 40 individuals had high levels of genetic diversity, with the mean polymorphism information content of 0.620 2. Results from SSR molecular markers based phylogenetic analysis showed that the 40 individuals had varying phylogenetic relationships, belonged to 23 homogenous groups. To effectively control inbreeding, the 40 individuals were conducted within-homogenous group selection and finally only 23 superior individuals were remained and used for parents of seed orchard in the second breeding cycle. Combined with the results of volume dominance ratios and phylogenetic analysis of these parents, seed orchard in the second breeding cycle of Zhongwan Improved Variety Base was suggested to adopt the grouped, unbalanced, complete, fixed block design, which had taken the increase of volume genetic gain and the maintenance of genetic diversity of seed orchrd progenies into consideration simultaneously. Results from this study will provide new insights into effective selection and rational utilization of elite germplasm resources in advanced breeding cycles of Chinese pine, and will lay the foundation for shortening breeding cycle and increasing breeding efficiency in genetic improvement of Chinese pine.
Abstract:
Evapotranspiration (ET) is one of the key processes of terrestrial energy/water transfer and carbon exchange, and it is also an important factor affecting regional climate and global carbon cycle. It is important to simulate ET over forest ecosystem to evaluate the role of forests in surface water cycle. In this paper, the Penman-Monteith (P-M) model and the Shuttleworth-Wallace (S-W) model were used to simulate ET over a mixed plantation in the southern foot of the Taihang Mountain, northern China. The mixed plantation is mainly composed ofQuercus variabilis,Platycladus orientalisandRobinia pseudoacacia. In order to evaluate the model applicability, ET simulated by the S-W model and the P-M model was compared with the measured one obtained by the eddy covariance technique. In addition, the sensitivities of P-M and S-W models to their resistance parameters were analyzed and the diurnal and seasonal variations in ET were explored. ET simulated by the S-W model and the P-M model was about 6% and 21% lower than the measured ET, respectively. Compared with the S-W model, ET simulated by the P-M model was less than the measured one. Compared with the P-M model, the correlation coefficient, agreement index, root mean square error, mean absolute error between measured ET and simulated ET by the S-W model were lower. The fitted curve of the relation between ET simulated by the S-W model and measured ET was closer to the 1:1 line than P-M model. Accordingly, ET simulated by the S-W model was higher than P-M model. It was suggested that the S-W model was more suitable for simulating ET in this region, and ET simulated by the P-M model was low. ET simulated by the P-M model and the S-W model was most sensitive to the change of canopy resistance. The second sensitive parameter was the aerodynamic resistance from canopy to reference height for the S-W model, and it was insensitive to the aerodynamic resistance from soil to the canopy. Transpiration and evaporation were most sensitive to the canopy resistance and soil surface resistance, respectively. There were no significant differences between the diurnal and seasonal variations in ET simulated by the S-W model and the P-M model, but the simulation accuracy of the S-W model was higher than P-M model. ET simulated by the P-M model in 2009 was obviously lower than the measured one. The ratio ofEto ET was 11.3%, andEaccounted for 10% of total ET simulated by the S-W model. Therefore, the possible reason was that soil surface resistance was not taken into account in the P-M model. The reason of the deference between simulated ET by the S-W model and the P-M model and measured ET may be that the empirical coefficients in the models are different for any vegetation types, especially how to choose the suitable resistance parameters. Moreover, meteorological factors are different in varied regions, which will influence the model accuracy. Accordingly, in order to improve the model accuracy, the climate and environment situation in study area should be taken into account to find a suitable resistance parameter of the model.
Evapotranspiration (ET) is one of the key processes of terrestrial energy/water transfer and carbon exchange, and it is also an important factor affecting regional climate and global carbon cycle. It is important to simulate ET over forest ecosystem to evaluate the role of forests in surface water cycle. In this paper, the Penman-Monteith (P-M) model and the Shuttleworth-Wallace (S-W) model were used to simulate ET over a mixed plantation in the southern foot of the Taihang Mountain, northern China. The mixed plantation is mainly composed ofQuercus variabilis,Platycladus orientalisandRobinia pseudoacacia. In order to evaluate the model applicability, ET simulated by the S-W model and the P-M model was compared with the measured one obtained by the eddy covariance technique. In addition, the sensitivities of P-M and S-W models to their resistance parameters were analyzed and the diurnal and seasonal variations in ET were explored. ET simulated by the S-W model and the P-M model was about 6% and 21% lower than the measured ET, respectively. Compared with the S-W model, ET simulated by the P-M model was less than the measured one. Compared with the P-M model, the correlation coefficient, agreement index, root mean square error, mean absolute error between measured ET and simulated ET by the S-W model were lower. The fitted curve of the relation between ET simulated by the S-W model and measured ET was closer to the 1:1 line than P-M model. Accordingly, ET simulated by the S-W model was higher than P-M model. It was suggested that the S-W model was more suitable for simulating ET in this region, and ET simulated by the P-M model was low. ET simulated by the P-M model and the S-W model was most sensitive to the change of canopy resistance. The second sensitive parameter was the aerodynamic resistance from canopy to reference height for the S-W model, and it was insensitive to the aerodynamic resistance from soil to the canopy. Transpiration and evaporation were most sensitive to the canopy resistance and soil surface resistance, respectively. There were no significant differences between the diurnal and seasonal variations in ET simulated by the S-W model and the P-M model, but the simulation accuracy of the S-W model was higher than P-M model. ET simulated by the P-M model in 2009 was obviously lower than the measured one. The ratio ofEto ET was 11.3%, andEaccounted for 10% of total ET simulated by the S-W model. Therefore, the possible reason was that soil surface resistance was not taken into account in the P-M model. The reason of the deference between simulated ET by the S-W model and the P-M model and measured ET may be that the empirical coefficients in the models are different for any vegetation types, especially how to choose the suitable resistance parameters. Moreover, meteorological factors are different in varied regions, which will influence the model accuracy. Accordingly, in order to improve the model accuracy, the climate and environment situation in study area should be taken into account to find a suitable resistance parameter of the model.
2017, 39(11): 45-55.
doi:10.13332/j.1000-1522.20170204
Abstract:
In this study, the generalized linear mixed model was used to study the distribution of number of first-order branch for plantedLarix olgensistrees. The modeling data were based on 596 first-order branches of 49 branch analysis trees selected from 7 permanent sample plots inLarix olgensisplantation from Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province of northeastern China. Poisson model was introduced to develop the optimal basic model with the PROC GLIMMIX procedure of SAS. Considering the different tree effects, the generalized linear mixed model of number of first-order branch per 0.5 m was developed on the selected optimal basic model. AIC, BIC, -2log likelihood and LRT test were selected to compare the goodness-of-fit statistics of the models. The results showed that all of the convergence mixed models with the combination of random coefficients fitted better than the basic model. Finally, the one with three random coefficients (including DINC, LnRDINC, RDINC2) was selected as the optimal mixed model to describe the distribution of number of first-order branch per 0.5 m for plantedLarix olgensistrees. In this model, the parameter values for LnRDINC and CL were positive; the ones for DINC, RDINC2, HT/DBH, DBH were negative. Moreover, there was a peak value for the number of first-order branch per 0.5 m. The fitting result of model showed that the coefficient of determination (R2) was 0.669 and the mean absolute error was 2.250 and the root mean square error was 3.012. All in all, not only could the mixed model describe the mean trend of the branch distribution, but also it reflected the differences among sample trees. It was shown that the generalized linear mixed model could improve the simulation accuracy of the model. As a result, the optimal mixed model would be suitable for predicting the first-order branch quantity and will provide theoretic basis to modeling crown architecture and three-dimension visualization forLarix olgensisplantation.
In this study, the generalized linear mixed model was used to study the distribution of number of first-order branch for plantedLarix olgensistrees. The modeling data were based on 596 first-order branches of 49 branch analysis trees selected from 7 permanent sample plots inLarix olgensisplantation from Mengjiagang Forest Farm, Jiamusi City, Heilongjiang Province of northeastern China. Poisson model was introduced to develop the optimal basic model with the PROC GLIMMIX procedure of SAS. Considering the different tree effects, the generalized linear mixed model of number of first-order branch per 0.5 m was developed on the selected optimal basic model. AIC, BIC, -2log likelihood and LRT test were selected to compare the goodness-of-fit statistics of the models. The results showed that all of the convergence mixed models with the combination of random coefficients fitted better than the basic model. Finally, the one with three random coefficients (including DINC, LnRDINC, RDINC2) was selected as the optimal mixed model to describe the distribution of number of first-order branch per 0.5 m for plantedLarix olgensistrees. In this model, the parameter values for LnRDINC and CL were positive; the ones for DINC, RDINC2, HT/DBH, DBH were negative. Moreover, there was a peak value for the number of first-order branch per 0.5 m. The fitting result of model showed that the coefficient of determination (R2) was 0.669 and the mean absolute error was 2.250 and the root mean square error was 3.012. All in all, not only could the mixed model describe the mean trend of the branch distribution, but also it reflected the differences among sample trees. It was shown that the generalized linear mixed model could improve the simulation accuracy of the model. As a result, the optimal mixed model would be suitable for predicting the first-order branch quantity and will provide theoretic basis to modeling crown architecture and three-dimension visualization forLarix olgensisplantation.
Abstract:
The Yangtze River Basin has become the most intensive area of mountain torrent disasters in China because of its complex geological topography and climatic conditions. Susceptibility zoning of the mountain torrent disasters is of significance to the integrated disaster prevention system. The study on the susceptibility of mountain torrent disasters in view of the large-scale(inter-provincial) region of the Yangtze River Basin can provide scientific basis for the study of planning, deployment and implementation of mountain torrent disaster prevention in the Yangtze River Basin and similar areas. The assessment indices were established for the susceptibility evaluation of three kinds of mountain torrent disasters in the Yangtze River Basin, based on the affecting mechanism of natural geographical factors on the formation of the mountain torrent with county as assessment unit. The susceptible indicators for three kinds of mountain torrent disasters were calculated based on the method of analytic hierarchy process (AHP) using Matlab. The Yangtze River Basin was classified into four susceptibility degrees of areas for three kinds of the mountain torrent disasters, i.e. highly-susceptible area, medium-susceptible area, lowly-susceptible area and insusceptible area, using classification scheme by ArcGIS natural spacing. The river flood disaster showed a tendency to decrease gradually from east to west, and centered in the middle and eastern basin. The highly-susceptible area of landslide disaster is mainly in the middle of the basin and certain areas like northern Yunnan and the mountains of Longnan, southern Gansu in the upstream of the river, with the most concentrated area in the east of Sichuan Basin. The highly-susceptible area of debris flow disaster is mainly in the west of the basin, and happened most frequently on fault zones in the first and second ladder transition districts. The results showed obvious differences in the distribution of different mountain torrent disasters in the basin. Over 80% of historical disasters were located in the assessed highly-susceptibility area for all three types of mountain torrent disasters. The assessment results can well indicate the regional distributions of different types of mountain torrents.
The Yangtze River Basin has become the most intensive area of mountain torrent disasters in China because of its complex geological topography and climatic conditions. Susceptibility zoning of the mountain torrent disasters is of significance to the integrated disaster prevention system. The study on the susceptibility of mountain torrent disasters in view of the large-scale(inter-provincial) region of the Yangtze River Basin can provide scientific basis for the study of planning, deployment and implementation of mountain torrent disaster prevention in the Yangtze River Basin and similar areas. The assessment indices were established for the susceptibility evaluation of three kinds of mountain torrent disasters in the Yangtze River Basin, based on the affecting mechanism of natural geographical factors on the formation of the mountain torrent with county as assessment unit. The susceptible indicators for three kinds of mountain torrent disasters were calculated based on the method of analytic hierarchy process (AHP) using Matlab. The Yangtze River Basin was classified into four susceptibility degrees of areas for three kinds of the mountain torrent disasters, i.e. highly-susceptible area, medium-susceptible area, lowly-susceptible area and insusceptible area, using classification scheme by ArcGIS natural spacing. The river flood disaster showed a tendency to decrease gradually from east to west, and centered in the middle and eastern basin. The highly-susceptible area of landslide disaster is mainly in the middle of the basin and certain areas like northern Yunnan and the mountains of Longnan, southern Gansu in the upstream of the river, with the most concentrated area in the east of Sichuan Basin. The highly-susceptible area of debris flow disaster is mainly in the west of the basin, and happened most frequently on fault zones in the first and second ladder transition districts. The results showed obvious differences in the distribution of different mountain torrent disasters in the basin. Over 80% of historical disasters were located in the assessed highly-susceptibility area for all three types of mountain torrent disasters. The assessment results can well indicate the regional distributions of different types of mountain torrents.
2017, 39(11): 65-74.
doi:10.13332/j.1000-1522.20170163
Abstract:
Vegetative filter strip (VFS) is one of the commonly used practices for soil and water conservation and non-point source pollution control. In August 2016, a simulated scouring experiment on soil boxes was conducted in Beijing to quantitatively evaluate the interception and removing effects of VFS (all planted withFestuca arundinacea) on runoff, total suspended solid (TSS), and pollutants (TN, TP, K). The differences between volumes of runoff and concentrations of TSS, TN, TP and K of the inflow and outflow of VFSs with different width, slope and inflow rate were examined to analyze the influence of width, slope and inflow rate on soil and water conservation and water purification effects of VFS. The results showed that the runoff reduction rate was greatly influenced by the width of VFS. The VFSs with 1, 3, and 5 m width could reduce runoff by 25.9%, 79.6% and 79.7%, respectively; the reduction rate of pollutants(TN, TP, K) increased with the increasing width, which were 51.7%-92.9%, 44.4%-98.8%, and 31.7%-97.9% correspondingly; and the reduction rate of TSS was 97.6%, 99.4% and 77.4%, respectively. Besides, the reduction rates of runoff and TSS decreased with increasing slope of VFS (3°, 7°, 10°). For the same VFS, decreasing inflow rate corresponded to increasing reduction rate of runoff and TSS, while the removal efficiencies of TN, TP and K were decreasing. The results indicate that VFS is an effective practice for reducing runoff, removing TSS and pollutants.
Vegetative filter strip (VFS) is one of the commonly used practices for soil and water conservation and non-point source pollution control. In August 2016, a simulated scouring experiment on soil boxes was conducted in Beijing to quantitatively evaluate the interception and removing effects of VFS (all planted withFestuca arundinacea) on runoff, total suspended solid (TSS), and pollutants (TN, TP, K). The differences between volumes of runoff and concentrations of TSS, TN, TP and K of the inflow and outflow of VFSs with different width, slope and inflow rate were examined to analyze the influence of width, slope and inflow rate on soil and water conservation and water purification effects of VFS. The results showed that the runoff reduction rate was greatly influenced by the width of VFS. The VFSs with 1, 3, and 5 m width could reduce runoff by 25.9%, 79.6% and 79.7%, respectively; the reduction rate of pollutants(TN, TP, K) increased with the increasing width, which were 51.7%-92.9%, 44.4%-98.8%, and 31.7%-97.9% correspondingly; and the reduction rate of TSS was 97.6%, 99.4% and 77.4%, respectively. Besides, the reduction rates of runoff and TSS decreased with increasing slope of VFS (3°, 7°, 10°). For the same VFS, decreasing inflow rate corresponded to increasing reduction rate of runoff and TSS, while the removal efficiencies of TN, TP and K were decreasing. The results indicate that VFS is an effective practice for reducing runoff, removing TSS and pollutants.
2017, 39(11): 75-81.
doi:10.13332/j.1000-1522.20170214
Abstract:
In order to investigate the insecticidal activity and mechanism of matrine, oxymatrine and kaempferol on 3rd instar larvae ofLymantria dispar, the effects of three plant secondary metabolites on the survival and three enzymes (GST, AChE and CarE) ofL. disparwere analyzed by bioassay,in vitroandin vivoenzyme activity assay. The results indicated that matrine, oxymatrine and kaempferol all possessed a highly insecticidal activity on 3rd instar larvae ofL. dispar, and matrine showed the highest insecticidal activity among three plant secondary metabolites with a LC50value of 0.420 mg/mL.In vitroenzyme activity assays showed that the activities of GST, AChE and CarE could be inhibited by three plant secondary metabolites. The IC50values of oxymatrine against GST and AChE were 0.928 and 0.717 mg/mL, respectively, while the IC50value of matrine against CarE was 0.436 mg/mL, which was the highest inhibition. Furthermore, the results ofin vivoenzyme activity assay indicated that matrine had the highest inhibition on GST, which showed the lowest activity at 48 hours after treatment and was 39% of the control at the same stage. Moreover, oxymatrine had the highest inhibition on AChE and CarE, and their activities were 44% and 40% of the control at 72 hours after treatment, respectively.The above results indicate that the inhibition of matrine, oxymatrine and kaempferol on three enzymes (GST, AChE and CarE) ofL. disparis one of the reasons for their insecticidal activity.
In order to investigate the insecticidal activity and mechanism of matrine, oxymatrine and kaempferol on 3rd instar larvae ofLymantria dispar, the effects of three plant secondary metabolites on the survival and three enzymes (GST, AChE and CarE) ofL. disparwere analyzed by bioassay,in vitroandin vivoenzyme activity assay. The results indicated that matrine, oxymatrine and kaempferol all possessed a highly insecticidal activity on 3rd instar larvae ofL. dispar, and matrine showed the highest insecticidal activity among three plant secondary metabolites with a LC50value of 0.420 mg/mL.In vitroenzyme activity assays showed that the activities of GST, AChE and CarE could be inhibited by three plant secondary metabolites. The IC50values of oxymatrine against GST and AChE were 0.928 and 0.717 mg/mL, respectively, while the IC50value of matrine against CarE was 0.436 mg/mL, which was the highest inhibition. Furthermore, the results ofin vivoenzyme activity assay indicated that matrine had the highest inhibition on GST, which showed the lowest activity at 48 hours after treatment and was 39% of the control at the same stage. Moreover, oxymatrine had the highest inhibition on AChE and CarE, and their activities were 44% and 40% of the control at 72 hours after treatment, respectively.The above results indicate that the inhibition of matrine, oxymatrine and kaempferol on three enzymes (GST, AChE and CarE) ofL. disparis one of the reasons for their insecticidal activity.
Abstract:
The annual rainfall in North China is less than normal and the rainfall is concentrated. Rainstorms frequently occurs and the annual evaporation is large, which cause serious flood and water shortage problems. The rainstorms in the windward area of the piedmont area constitute a threat of flood to the plain area. Building greenway in urban shallow mountainous area is of great significance to alleviate flood and rain disasters. With the aim of solving the problems of the water resource shortage in northern China and rainwater management problems in urban shallow mountainous areas, firstly, this paper discusses the necessity of sponge greenway's construction by analyzing the climatic characteristics of northern China and characteristics of rain and flood disasters in urban shallow mountainous area. On this basis, combined with the greenway project of Luquan District in Shijiazhuang, Hebei Province of northern China, the paper proposes design methods for spongy greenway. The design strategies of sponge greenway consider three following dimensions: 1) taking urban mountainous areas of northern China as the natural substrates; 2) taking greenway as the runoff buffer; 3) integrating the LID facilities into greenway design. This study considers the design strategies based on two perspectives of rainwater safety and utilization. Finally, this paper uses the storm water management model (SWMM) to quantify the control effect of LID facilities on stormwater runoff, and compares the storage efficiency of sponge greenway with the traditional one. The results show that the sponge greenway has better efficiency in controlling total runoff, peak flow and delaying peak time. Spongy greenway can effectively solve the problems of rainwater regulation.
The annual rainfall in North China is less than normal and the rainfall is concentrated. Rainstorms frequently occurs and the annual evaporation is large, which cause serious flood and water shortage problems. The rainstorms in the windward area of the piedmont area constitute a threat of flood to the plain area. Building greenway in urban shallow mountainous area is of great significance to alleviate flood and rain disasters. With the aim of solving the problems of the water resource shortage in northern China and rainwater management problems in urban shallow mountainous areas, firstly, this paper discusses the necessity of sponge greenway's construction by analyzing the climatic characteristics of northern China and characteristics of rain and flood disasters in urban shallow mountainous area. On this basis, combined with the greenway project of Luquan District in Shijiazhuang, Hebei Province of northern China, the paper proposes design methods for spongy greenway. The design strategies of sponge greenway consider three following dimensions: 1) taking urban mountainous areas of northern China as the natural substrates; 2) taking greenway as the runoff buffer; 3) integrating the LID facilities into greenway design. This study considers the design strategies based on two perspectives of rainwater safety and utilization. Finally, this paper uses the storm water management model (SWMM) to quantify the control effect of LID facilities on stormwater runoff, and compares the storage efficiency of sponge greenway with the traditional one. The results show that the sponge greenway has better efficiency in controlling total runoff, peak flow and delaying peak time. Spongy greenway can effectively solve the problems of rainwater regulation.
Abstract:
Plant diversity is important component of biodiversity, and garden plants are the main parts of urban ecological system. The maintenance of urban biodiversity depends on the diversity of urban plants, native plants are important part of urban plants, even the necessary condition of making characteristics of urban plant landscape. As for the abundant resources of native plants in Chongqing of southwestern China, aim at weakness in the application of native plants in roof greening, we did survey of 31green roofs of central districts of Chongqing by sample survey. We got that there were 110 species of plants. Then we summarized and analyzed the characteristics of roof plants in application and configuration, frequency, ornamental value and so on. But native plants only accounted for about 13.64%. After summarized datum in the 3 levels, we got a phanomenon that the species and application frequency of native plants are relatively few. Therefore, the staffs should attach importance to native plants. It is imperative to exploit native plants. Based on the results, a list of native plants for developing and popularizing were suggested. We should be aware of their characteristics and gradually being applied to roof greening. Finally, the strategy and suggestion are proposed on the protection and exploitation of native plant resources, and the construction of urban green space using these resources in Chongqing City.
Plant diversity is important component of biodiversity, and garden plants are the main parts of urban ecological system. The maintenance of urban biodiversity depends on the diversity of urban plants, native plants are important part of urban plants, even the necessary condition of making characteristics of urban plant landscape. As for the abundant resources of native plants in Chongqing of southwestern China, aim at weakness in the application of native plants in roof greening, we did survey of 31green roofs of central districts of Chongqing by sample survey. We got that there were 110 species of plants. Then we summarized and analyzed the characteristics of roof plants in application and configuration, frequency, ornamental value and so on. But native plants only accounted for about 13.64%. After summarized datum in the 3 levels, we got a phanomenon that the species and application frequency of native plants are relatively few. Therefore, the staffs should attach importance to native plants. It is imperative to exploit native plants. Based on the results, a list of native plants for developing and popularizing were suggested. We should be aware of their characteristics and gradually being applied to roof greening. Finally, the strategy and suggestion are proposed on the protection and exploitation of native plant resources, and the construction of urban green space using these resources in Chongqing City.
2017, 39(11): 98-105.
doi:10.13332/j.1000-1522.20170223
Abstract:
This study aims to investigate the effects of different forms of locks on the mechanical properties of wood flooring, in which the lock plays a key role to the connection. The laminate flooring lock structure was investigated, and the static characteristics of finite element model of the lock structure was taken as the research objective. By means of 3D scanner, the 3D point cloud data of 12 kinds of typical lock structures including embedded lock and body lock were acquired. The 3D solid model of lock structure was reversely reconstructed, and the characteristics of lock structure were analyzed to determine the structure eigenvalues affecting the mechanical properties of the lock. The finite element software ANSYS was used to analyze the finite element models of the total deformation, the equivalent stress, the equivalent strain under bending or tensile loads, and to study the static characteristics of the wood flooring lock. The results showed that the mechanical properties of the lock were most affected by locking junction length, the tenon/groove (convex/concave) length and joint surface shape. The embedded lock performed better overall properties than the body lock, as it was less affected by the shape of the lock but most affected by the shape of the locking element. In a body lock structure, the shape of a large arc lock section is beneficial to the improve the mechanical properties. The study provides a new approach to design, optimize and test the flooring lock.
This study aims to investigate the effects of different forms of locks on the mechanical properties of wood flooring, in which the lock plays a key role to the connection. The laminate flooring lock structure was investigated, and the static characteristics of finite element model of the lock structure was taken as the research objective. By means of 3D scanner, the 3D point cloud data of 12 kinds of typical lock structures including embedded lock and body lock were acquired. The 3D solid model of lock structure was reversely reconstructed, and the characteristics of lock structure were analyzed to determine the structure eigenvalues affecting the mechanical properties of the lock. The finite element software ANSYS was used to analyze the finite element models of the total deformation, the equivalent stress, the equivalent strain under bending or tensile loads, and to study the static characteristics of the wood flooring lock. The results showed that the mechanical properties of the lock were most affected by locking junction length, the tenon/groove (convex/concave) length and joint surface shape. The embedded lock performed better overall properties than the body lock, as it was less affected by the shape of the lock but most affected by the shape of the locking element. In a body lock structure, the shape of a large arc lock section is beneficial to the improve the mechanical properties. The study provides a new approach to design, optimize and test the flooring lock.
2017, 39(11): 106-113.
doi:10.13332/j.1000-1522.20170221
Abstract:
To analyze the deformation and strain distribution of wood beams which contained holes during loading, in this paper, four-point bending tests were performed on clear wood beams and wood beams containing holes using digital image correlation technique. The influence of three various locations of holes (a hole located at center, located at compression zone, and located at tension zone, respectively) on bending strain distributions of wood beams was analyzed, and the movement of the neutral axis during loading was discussed. The experiment results showed that strain distributions and neutral axis locations were significantly different for three various locations of holes. When beams were at the ultimate load, for beams containing holes at various locations, the compressive strain region was larger than the tensile strain region. Among three various locations of holes, wood beams containing a hole in the compression zone had the largest compressive strain region, beams containing a hole at center come second, and beams containing a hole in the tension zone had the smallest compressive strain region. Additionally, the neutral axis moved towards the bottom of the beam as the load increased during loading. The movement of neutral axis was largest when the hole located at the compression zone, secondly when the hole located at center, and smallest when the hole located at the tension zone. Based on plane-section assumption and Hoffman yield criterion in elastic-plastic theory, the theoretical analysis of strain distribution and movement of neutral axis was studied on wood beams which contained holes. The results provide proofs for further theoretical study on bending properties of wood beams containing holes.
To analyze the deformation and strain distribution of wood beams which contained holes during loading, in this paper, four-point bending tests were performed on clear wood beams and wood beams containing holes using digital image correlation technique. The influence of three various locations of holes (a hole located at center, located at compression zone, and located at tension zone, respectively) on bending strain distributions of wood beams was analyzed, and the movement of the neutral axis during loading was discussed. The experiment results showed that strain distributions and neutral axis locations were significantly different for three various locations of holes. When beams were at the ultimate load, for beams containing holes at various locations, the compressive strain region was larger than the tensile strain region. Among three various locations of holes, wood beams containing a hole in the compression zone had the largest compressive strain region, beams containing a hole at center come second, and beams containing a hole in the tension zone had the smallest compressive strain region. Additionally, the neutral axis moved towards the bottom of the beam as the load increased during loading. The movement of neutral axis was largest when the hole located at the compression zone, secondly when the hole located at center, and smallest when the hole located at the tension zone. Based on plane-section assumption and Hoffman yield criterion in elastic-plastic theory, the theoretical analysis of strain distribution and movement of neutral axis was studied on wood beams which contained holes. The results provide proofs for further theoretical study on bending properties of wood beams containing holes.
2017, 39(11): 114-124.
doi:10.13332/j.1000-1522.20170142
Abstract:
Water deficiency is a major global constraint for plant productivity that is likely to be exacerbated by climate change. Hence, improving plant water use efficiency (WUE) has become a major goal in the near future. WUE reflects the coupling of carbon and water cycles in plant-soil-atmosphere continuum. Analyzing WUE can improve our understanding of the interaction between carbon and water cycles in terrestrial ecosystems. Stable carbon isotope analysis has become the most effective techniques in plant ecological research. As an indicator, foliar carbon isotope discrimination (δ13C) is often used to evaluate long-term WUE in C3plants. Study of δ13C and WUE can help to reveal and predict the response and adaptation of forest vegetation to global climate change. In this paper, the mechanism of characterization of δ13C and WUE, the factors influencing plant δ13C and WUE, including leaf traits, plant ecophysiology, climate factors, genetic control and genetic variation were summarized. The impacts of water stress and acid deposition on plant δ13C and WUE were also discussed. Plant stomatal conductance, specific leaf area, leaf nitrogen content, intercellular CO2concentration, and atmospheric CO2concentration were proposed to be the dominant factors influencing WUE variations due to their direct or indirect effects on plant net photosynthesis and transpiration rate. Generally, plants display higher WUE and lower δ13C when exposed to drought stress, and lower stomatal conductance and photosynthesis under long-term acid deposition. Nitrogen input will enhance plant productivity by improving water use efficiency. We suggest that the key role of quantitative trait loci, carbonic anhydrase, aquaporins, large and small subunits gene of Rubisco in the process of WUE genetic control must be highlighted when using stable isotope technique to study plant WUE. Finally, we must strengthen the study of multiple temporal and spatial scale variation and explore the application of combing analysis of δ13C and δ18O on the dual isotope conceptual model.
Water deficiency is a major global constraint for plant productivity that is likely to be exacerbated by climate change. Hence, improving plant water use efficiency (WUE) has become a major goal in the near future. WUE reflects the coupling of carbon and water cycles in plant-soil-atmosphere continuum. Analyzing WUE can improve our understanding of the interaction between carbon and water cycles in terrestrial ecosystems. Stable carbon isotope analysis has become the most effective techniques in plant ecological research. As an indicator, foliar carbon isotope discrimination (δ13C) is often used to evaluate long-term WUE in C3plants. Study of δ13C and WUE can help to reveal and predict the response and adaptation of forest vegetation to global climate change. In this paper, the mechanism of characterization of δ13C and WUE, the factors influencing plant δ13C and WUE, including leaf traits, plant ecophysiology, climate factors, genetic control and genetic variation were summarized. The impacts of water stress and acid deposition on plant δ13C and WUE were also discussed. Plant stomatal conductance, specific leaf area, leaf nitrogen content, intercellular CO2concentration, and atmospheric CO2concentration were proposed to be the dominant factors influencing WUE variations due to their direct or indirect effects on plant net photosynthesis and transpiration rate. Generally, plants display higher WUE and lower δ13C when exposed to drought stress, and lower stomatal conductance and photosynthesis under long-term acid deposition. Nitrogen input will enhance plant productivity by improving water use efficiency. We suggest that the key role of quantitative trait loci, carbonic anhydrase, aquaporins, large and small subunits gene of Rubisco in the process of WUE genetic control must be highlighted when using stable isotope technique to study plant WUE. Finally, we must strengthen the study of multiple temporal and spatial scale variation and explore the application of combing analysis of δ13C and δ18O on the dual isotope conceptual model.
