摘要: 目的� 、氮 元素对植物的生长发育至关重要，尤其是在极端干旱的内陆河流域，不同功能群植物对土壤水分和养分需求不同，往往表现出不同的化学计量特征。探寻黑河下游不同功能群植物的化学计量特征及对地下水变化的养分反应，对进一步了解全球气候变化背景下荒漠生态系统具有重要意义、�/sec> 方法在黑河下游，根据与河道的距离，共设置22个采样点，采用相关性分析、方差分解方法分别对不同功能群植物的碳氮化学计量特征及其与环境因子的关系进行研究、�/sec> 结果研究结果表明：黑河下游地区植物叶片和细根的碳、氮元素含量平均值分别为408.53�?6.30 mg/g�?00.34�?1.81 mg/g，碳氮比平均值分别为30.74�?9.48，与全球和区域尺度研究相比，黑河下游植物具有较高的细根碳含量、较低的氮含量和较高的碳氮比。在不同地下水位梯度上，木本植物的碳含量、氮含量与碳氮比均与地下水深度显著相关，但草本植物与地下水不相关。黑河下游植物碳氮化学计量特征与土壤理化属性紧密相关。地下水和土壤含水量、土壤总氮共同解释了木本植物化学计量总变异的53% ~ 75%；土壤pH值和土壤电导率共同解释了草本植物化学计量总变异的20%、�/sec> 结论研究表明面对极端干旱盐碱环境，水分是影响木本植物碳氮化学计量特征变化的关键因子，草本植物碳氮化学计量特征主要受土壤pH值和土壤电导率影响、�/sec>

关键诌�
• 地下氳�/a> /
• 黑河/
• 碳氮/
• 化学计量特征/
• 功能羣�/a>

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 and N contents in leaves and fine roots in the lower reaches of Heihe River were 408.53, 16.30, 500.34 and 11.81 mg/g, respectively. 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.

Key words:
• groundwater/
• Heihe River/
• carbon and nitrogen/
• stoichiometric characteristics/
• functional group

�?nbsp; 1采样点示意图

Figure 1.Schematic diagram of sampling points

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�?nbsp; 2木本植物碳氮化学计量特征与地下水深度关系

Figure 2.Relationship between carbon and nitrogen stoichiometric characteristics of woody plants and underground water depth

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�?nbsp; 3草本植物碳氮化学计量特征与地下水深度关系

Figure 3.Relationship between carbon and nitrogen stoichiometric characteristics of herbaceous plants and underground water depth

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�?nbsp; 4环境因子对木本植物叶片和细根的碳、氮化学计量特征的解釉�/p>

GW.地下水；SM1.土壤0 ~ 20 cm含水量；SM2.土壤20 ~ 40 cm含水量；SM4.土壤60 ~ 100 cm含水量；SEC.土壤电导率；STN.土壤TN含量；NE.未解释率。下同。GW, underground water; SM1, 0�?0 cm soil water content; SM2, 20�?0 cm soil water content; SM4, 60�?00 cm soil water content; SEC, soil electrical conductivity; STN, soil total nitrogen content; NE, no-explanation rate. The same below.

Figure 4.Explanation of environmental factors on the carbon and nitrogen stoichiometric characteristics of leaves and fine roots of woody plants

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�?nbsp; 5环境因子对草本植物叶片和细根的碳、氮化学计量特征的解釉�/p>

pH.土壤pH；SEC.土壤电导率。pH, soil pH；SEC, soil electrical conductivity.

Figure 5.Interpretation of environmental factors on the carbon and nitrogen stoichiometric characteristics of herbaceous leaves and fine roots

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�?nbsp; 1采样点基本信�?/p>

Table 1.Basic information of the sampling sites

样点 Sample site	地下水深� Underground water depth/m	木本植物 Woody plant			草本植物 Herb
		优势秌�br/>Dominant species	重要倻�br/>Importance value		优势秌�br/>Dominant species	重要倻�br/>Importance value
S1	1.46	多枝柽柳Tamarix ramosissima	0.53
S2	1.51	胡杨Populus euphratica	0.58		苦豆�Sophora alopecuroides	0.37
S3	1.77	胡杨Populus euphratica	0.63		苦豆�Sophora alopecuroides	0.21
S4	1.78	胡杨Populus euphratica	0.48		胀果甘�Glycyrrhiza inflata	0.14
S5	1.96	多枝柽柳Tamarix ramosissima	0.68		骆驼�Peganum harmala	0.32
S6	2	黑果枸杞Lycium ruthenicum	0.23		苦豆�Sophora alopecuroides	0.49
S7	2.08	胡杨Populus euphratica	0.48		芨芨�Achnatherum splendens	0.42
S8	2.26	胡杨Populus euphratica	0.54		苦豆�Sophora alopecuroides	0.44
S9	2.3	多枝柽柳Tamarix ramosissima	0.35		花花�Karelinia caspia	0.39
S10	2.49	白刺Nitraria tangutorum	0.33		沙蒿Artemisia desertorum	0.38
S11	2.56	多枝柽柳Tamarix ramosissima	0.24		苦豆�Sophora alopecuroides	0.70
S12	2.73	红砂Reaumuria soongorica	0.80		沙蒿Artemisia desertorum	0.10
S13	2.79	膜果麻黄Ephedra przewalskii	0.43		驼蹄�Zygophyllum fabago	0.14
S14	2.85	骆驼�Alhagi sparsifolia	0.70		花花�Karelinia caspia	0.38
S15	2.89	红砂Reaumuria soongorica	0.37		花花�Karelinia caspia	0.54
S16	3	多枝柽柳Tamarix ramosissima	0.83		骆驼�Peganum harmala	0.26
S17	3.15	膜果麻黄Ephedra przewalskii	0.85
S18	3.3	红砂Reaumuria soongorica	0.71		骆驼�Peganum harmala	0.12
S19	3.31	膜果麻黄Ephedra przewalskii	0.47
S20	3.44	膜果麻黄Ephedra przewalskii	0.54
S21	3.55	膜果麻黄Ephedra przewalskii	0.85
S22	3.66	膜果麻黄Ephedra przewalskii	0.66

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�?nbsp; 2不同功能群植物的叶片和细根养分组戏�/p>

Table 2.Nutrient composition of leaves and fine roots of different functional groups of plants

指标 Index	总体 Total	木本植物 Woody plant	草本植物 Herb
叶片氮含� Leaf N concentration	16.30 ± 0.59	15.06 ± 0.75b	18.66 ± 1.02a
叶片碳含� Leaf C concentration	408.54 ± 10.89	396.80 ± 13.63a	429.05 ± 17.41a
叶片碳氮� Leaf C∶N	30.74 ± 1.44	31.69 ± 1.83a	29.30 ± 2.54a
细根氮含� Fine root N concentration	11.81 ± 0.44	12.61 ± 0.47a	10.42 ± 1.03b
细根碳含� Fine root C concentration	500.34 ± 15.10	514.52 ± 18.92a	484.33 ± 26.14a
细根碳氮� Fine root C∶N	49.49 ± 2.69	45.35 ± 3.09b	54.27 ± 5.14a
注：不同字母表示差异显著＇�i>P< 0.05）� Note: different letters indicate significant difference (P< 0.05).

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�?nbsp; 3土壤因子对不同功能群植物化学计量的影哌�/p>

Table 3.Effects of soil factors on plant stoichiometry of different functional groups

		电导玆�br/>Electrical conductivity	土壤pH Soil pH	0 ~ 20 cm 含水野�br/> 0�?0 cm water content	20 ~ 40 cm 含水野�br/> 20�?0 cm water content	40 ~ 60 cm 含水野�br/> 40�?0 cm water content	60 ~ 100 cm 含水野�br/> 60�?00 cm water content	土壤总碳 Soil total carbon	土壤全N Soil total nitrogen	土壤全P Soil total phosphorus
木本植物 Woody plant	叶片氮含� Leaf N concentration	�?.10	0.14	0.50**	0.48**	0.37**	0.39**	0.27*	0.21**	0.13
	叶片碳含野�br/> Leaf C concentration	0.03	0.04	�?.01	�?.05	�?.04	�?.24*	�?.03	0.20	0.11
	叶片碳氮毓�br/> Leaf C∶N	0.30*	�?.17	�?.28*	�?.28*	�?.25*	�?.35**	�?.15	�?.01	0.04
	细根氮含� Fine root N concentration	0.25	�?.32	�?.41**	�?.37**	�?.34**	�?.39**	�?.37**	�?.21**	0.19
	细根碳含� Fine root C concentration	�?.07	�?.06	�?.34**	0-.43**	�?.45**	�?.49**	�?.27*	�?.17	0.17
	细根碳氮� Fine root C∶N	�?.27*	0.27*	0.21	0.11	0.09	0.03	0.18	0.11	�?.05
草本植物 Herb	叶片氮含� Leaf N concentration	0.44*	�?.40*	�?.24	�?.30	�?.07	�?.18	�?.05	0.36	0.14
	叶片碳含野�br/> Leaf C concentration	�?.17	0.26	0.46*	0.13	0.24	0.32	0.23	0.01	�?.16
	叶片碳氮毓�br/> Leaf C∶N	�?.38*	0.44*	0.32	0.18	0.04	0.20	0.02	�?.31	�?.26
	细根氮含� Fine roo N concentration	0.42*	�?.45*	�?.29	�?.25	�?.20	�?.29	�?.21	0.07	0.58
	细根碳含� Fine roo C concentration	�?.16	0.25	0.14	0.11	0.04	0.13	0.15	0.13	0.09
	细根碳氮� Fine roo C∶N	�?.38*	0.48**	0.21	�?.01	0.00	0.13	0.12	0.02	�?.10
注：* 表示P< 0.05�?*表示P< 0.01．Notes: * indicatesP< 0.05; ** indicatesP< 0.01－�/td>

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[2]Zhu Y H, Chen Y N, Ren L L, et al. Ecosystem restoration and conservation in the arid inland river basins of Northwest China: problems and strategies[J]. Ecological Engineering, 2016, 94(1): 629�?37. [3]Zhang X L, Zhou J H, Guan T Y, et al. Spatial variation in leaf nutrient traits of dominant desert riparian plant species in an arid inland river basin of China[J]. Ecology and Evolution, 2019, 9(3): 1523�?531. doi:10.1002/ece3.4877 [4]Tamea S, Laio F, Ridolfi L, et al. Ecohydrology of groundwater-dependent ecosystems(2): stochastic soil moisture dynamics[J]. Water Resources Research, 2009, 45(5): 5420�?433. [5]古力米热·哈那�? 王光�? 张音, �? 干旱区间歇性生态输水对地下水位与植被的影响机理研究[J]. 干旱区地�? 2018, 41(4): 726�?33. doi:10.12118/j.issn.1000-6060.2018.04.07

Hanati·Gulimire, Wang G Y, Zhang Y, et al. Influence mechanism of intermittent ecological water conveyance on groundwater level and vegetation in arid land[J]. Arid Land Geography, 2018, 41(4): 726�?33. doi:10.12118/j.issn.1000-6060.2018.04.07 [6]Yao Y, Tian Y, Andrews C, et al. Role of groundwater in the dryland ecohydrological system: a case study of the Heihe River Basin[J]. Journal of Geophysical Research-atmospheres, 2018, 123: 6760�?776. doi:10.1029/2018JD028432 [7]Harper JL. The value of a leaf[J]. Oecologia, 1989, 80: 53�?8. doi:10.1007/BF00789931 [8]Castellanos A E, Llano-Sotelo J M, Machado-Encinas L I, et al. Foliar C, N, and P stoichiometry characterize successful plant ecological strategies in the Sonoran Desert[J]. Plant Ecology, 2018, 219: 775�?88. doi:10.1007/s11258-018-0833-3 [9]Sommer B, Froend R. Phreatophytic vegetation responses to groundwater depth in a drying Mediterranean type landscape[J]. Journal of Vegetation Science, 2014, 25: 1045�?055. doi:10.1111/jvs.12178 [10]Westheimer F. Why nature chose phosphates[J]. Science, 1987, 235(4793): 1173�?178. doi:10.1126/science.2434996 [11]Dawson T P, Curran P J. Technical note a new technique for interpolating the reflectance red edge position[J]. International Journal of Remote Sensing, 1998, 19(11): 2133�?139. doi:10.1080/014311698214910 [12]曾德�? 陈广�? 生态化学计量学: 复杂生命系统奥秘的探索[J]. 植物生态学�? 2005, 29(6): 141�?53.

Zeng D H, Chen G H. Ecological stoichiometry: a science to explore the complexity of living systems[J]. Chinese Journal of Plant Ecology, 2005, 29(6): 141�?53. [13]Han W X, Fang J Y, Guo D L, et al. Leaf nitrogen and phosphorus stoichiometry across 753 terrestrial plant species in China[J]. New Phytologist, 2005, 168: 377�?85. doi:10.1111/j.1469-8137.2005.01530.x [14]Marschner P, Rengel Z. Nutrient cycling in terrestrial ecosystems[J]. Soil Biology, 2007: 缺少卷期和页�? [15]Aroca R. Plant responses to drought stress[M]. Berlin: Springer, 2012. [16]Farooq M, Wahid A, Kobayashi N, et al. Plant drought stress: effects, mechanisms and management[J]. Agronomy for Sustainable Development, 2009, 29: 185�?12. doi:10.1051/agro:2008021 [17]向云�? 潘萍, 陈胜�? �? 天然马尾松林土壤碳氮磷特征及其与凋落物质量的关系[J]. 北京林业大学学报, 2019, 41(11): 95�?03.

Xiang Y X, Pan P, Chen S K, et al. Characteristics of soil C, N, P and their relationship with litter quality in natural Pinus massonianaforest[J]. Journal of Beijing Forestry University, 2019, 41(11): 95�?03. [18]张珂, 何明�? 李新�? �? 阿拉善荒漠典型植物叶片碳、氮、磷化学计量特征[J]. 生态学�? 2014, 34(22): 6538�?547.

Zhang K, He M Z, Li X R, et al. Foliar carbon, nitrogen and phosphorus stoichiometry of typical desert plants across the Alashan Desert[J]. Acta Ecologica Sinica, 2014, 34(22): 6538�?547. [19]Rong Q Q, Liu J T, Cai Y P, et al. Leaf carbon, nitrogen and phosphorus stoichiometry of Tamarix chinensisLour. in the Laizhou Bay Coastal Wetland, China[J]. Ecological Engineering, 2015, 76: 57�?5. doi:10.1016/j.ecoleng.2014.03.002 [20]Canadell J, Jackson R B, Ehleringer J B, et al. Maximum rooting depth of vegetation types at the global scale[J]. Oecologia, 1996, 108: 583�?95. doi:10.1007/BF00329030 [21]Luo Y, Peng Q, Li K, et al. Patterns of nitrogen and phosphorus stoichiometry among leaf, stem and root of desert plants and responses to climate and soil factors in Xinjiang, China[J]. Catena, 2021, 199: 105100. doi:10.1016/j.catena.2020.105100 [22]Wright I J, Reich P B, Westoby M, et al. The worldwide leaf economics spectrum[J]. Nature, 2004, 428: 821�?27. doi:10.1038/nature02403 [23]Xu Z Z, Zhou G S, Wang Y H. Combined effects of elevated CO ₂and soil drought on carbon and nitrogen allocation of the desert shrub Carag ana intermedia[J]. Plant and Soil, 2007, 301(1/2): 87�?7. [24]钟华�? 刘恒, 王义, �? 黑河流域下游额济纳绿洲与水资源的关系[J]. 水科学进�? 2002, 13(02): 223�?28. doi:10.3321/j.issn:1001-6791.2002.02.016

Zhong H P, Liu H, Wang Y, et al. Relationship between Ejina oasis and water resources in the lower Herhe River Basin[J]. Advances in Water Science, 2002, 13(02): 223�?28. doi:10.3321/j.issn:1001-6791.2002.02.016 [25]赵传�? 赵阳, 彭守�? �? 黑河下游绿洲胡杨生长状况与叶生态特征[J]. 生态学�? 2014, 34(16): 4518�?525.

Zhao C Y, Zhao Y, Peng S Z, et al. The growth state of Populus euphraticalOliv. and its leaf ecological characteristics in the lower reaches of Heihe River[J]. Acta Ecologica Sinica, 2014, 34(16): 4518�?525. [26]Wang R, Wang Q F, Zhao N, et al. Different phylogenetic and environmental controls of first-order root morphological and nutrient traits: evidence of multidimensional root traits[J]. Functional Ecology, 2017, 32: 29�?9. [27]王健�? 崔盼�? 钟悦�? �? 阿拉善高原植物区域物种丰富度格局及其环境解释[J]. 北京林业大学学报, 2019, 41(3): 14�?3.

Wang J M, Cui P J, Zhong Y M, et al. Biogeographic patterns and environmental interpretation of plant regional species richness in Alxa Plateau of northern China[J]. Journal of Beijing Forestry University, 2019, 41(3): 14�?3. [28]Agren G I. Stoichiometry and nutrition of plant growth in natural communities[J]. Annual Review of Ecology, Evolution and Systematics, 2008, 39(39): 153�?70. [29]Foulds W. Nutrient concentrations of foliage and soil in south-western Australia[J]. New Phytologist, 1993, 125(3): 529�?46. doi:10.1111/j.1469-8137.1993.tb03901.x [30]阎恩�? 王希�? 周武. 天童常绿阔叶林演替系列植物群落的N∶P化学计量特征[J]. 植物生态学�? 2008, 32(1): 13�?2. doi:10.3773/j.issn.1005-264x.2008.01.002

Yan E R, Wang X H, Zhou W. N∶P stoichiometry in secondary succession in evergreen broadleaved forest, Tiantong, East China[J]. Chinese Journal of Plant Ecology, 2008, 32(1): 13�?2. doi:10.3773/j.issn.1005-264x.2008.01.002 [31]Yuan Z Y, Chen H Y, Reich P B. Global-scale latitudinal patterns of plant fine-root nitrogen and phosphorus[J]. Nature Communications, 2011, 2: 344. doi:10.1038/ncomms1346 [32]李玉�? 毛伟, 赵学�? �? 北方典型荒漠及荒漠化地区植物叶片氮磷化学计量特征研究[J]. 环境科学, 2010, 31(8): 1716�?725.

Li Y L, Mao W, Zhao X Y, et al. Leaf nitrogen and phosphorus stoichiometry in typical desert and desertified regions, North China[J]. Environmental Science, 2010, 31(8): 1716�?725. [33]宁志�? 李玉�? 杨红�? �? 科尔沁沙地主要植物细根和叶片碳、氮、磷化学计量特征[J]. 植物生态学�? 2017, 41(10): 1069�?080. doi:10.17521/cjpe.2017.0048

Ning Z Y, Li Y L, Yang H L, et al. Carbon, nitrogen and phosphorus stoichiometry in leaves and fine roots of domiant plants in Horqin Sandy Land[J]. Chinese Journal of Plant Ecology, 2017, 41(10): 1069�?080. doi:10.17521/cjpe.2017.0048 [34]Herbert D A, Williams M, Rastetter E B. A model analysis of N and P limitation on carbon accumulation in Amazonian secondary forest after alternate land-use abandonment[J]. Biogeochemistry, 2003, 65(1): 121�?50. doi:10.1023/A:1026020210887 [35]Zhang Q, Xiong G M, Li J X, et al. Nitrogen and phosphorus concentrations and allocation strategies among shrub organs: the effects of plant growth forms and nitrogen-fixation types[J]. Plant and Soil, 2018, 427(1�?): 305�?19. doi:10.1007/s11104-018-3655-0 [36]Zhang K, Li M M, Su Y Z, et al. Stoichiometry of leaf carbon, nitrogen, and phosphorus along a geographic, climatic, and soil gradients in temperate desert of Hexi Corridor, northwest China[J]. Journal of Plant Ecology, 2019, 13(1): 114�?21. [37]何茂�? 罗艳, 彭庆�? �? 新疆45种荒漠植物粗根碳、氮、磷计量特征及其与环境的关系[J]. 生态学杂志, 2019, 38(9): 2603�?614.

He M S, Luo Y, Peng Q W, et al. Carbon, nitrogen and phosphorus stoichimentry in the coarse roots of 45 desert plant species in relation to environmental factors across the deserts in Xinjiang[J]. Chinese Journal of Ecology, 2019, 38(9): 2603�?614. [38]Vitousek P M, Howarth R W. Nitrogen limitation on land and in the sea: how can it occur[J]. Biogeochemistry, 1991, 13(2): 87�?15. [39]Yang Y H, Luo Y Q. Carbon: nitrogen stoichiometry in forest ecosystems during stand development[J]. Global Ecology and Biogeography, 2011, 20(2): 354�?61. doi:10.1111/j.1466-8238.2010.00602.x [40]王凯�? 上官周平. 黄土丘陵区燕沟流域典型植物叶片C、N、P化学计量特征季节变化[J]. 生态学�? 2011, 31(17): 4985�?991.

Wang K B, Shangguan Z P. Seasonal variations in leaf C, N and P stoichiometry of typical plants in the Yangou Watershed in the loess hilly gully region[J]. Acta Ecologica Sinica, 2011, 31(17): 4985�?991. [41]Sabine G. N∶P ratios in terrestrial plants: variation and functional significance[J]. New Phytologist, 2004, 164(2): 243�?66. doi:10.1111/j.1469-8137.2004.01192.x [42]Thompson K, Parkinson J A, Band S R, et al. A comparative study of leaf nutrient concentrations in a regional herbaceous flora[J]. New Phytologist, 1997, 136: 679�?89. doi:10.1046/j.1469-8137.1997.00787.x [43]Reich P B, Oleksyn J. Global patternsof plant leaf N and Pinrelation to temperature and latitude[J]. Proceedings of the National Academy of Sciences of the United States of America, 2004, 101: 11001�?1006. doi:10.1073/pnas.0403588101 [44]Zhang J H, He N P, Liu C C, et al. Allocation strategies for nitrogen and phosphorus in forest plants[J]. Oikos, 2018, 127(10): 1506�?514. doi:10.1111/oik.05517 [45]王振�? 杨惠�? 植物碳氮磷生态化学计量对非生物因子的响应[J]. 草业科学, 2013, 30(6): 927�?34.

Wang Z N, Yang H M. Response of ecological stoichiometry of carbon, nitrogen and phosphorus in plants to abiotic environmental factors[J]. Pratacultural Science, 2013, 30(6): 927�?34. [46]Li W, Yu T F, Li X Y, et al. Sap flow characteristics and their response to environmental variables in a desert riparian forest along lower Heihe River Basin, northwest China[J]. Environmental Monitoring and Assessment, 2016, 188: 561. doi:10.1007/s10661-016-5570-2 [47]钟悦�? 王文�? 王健�? �? 极端干旱区绿洲植物叶功能性状及其对土壤水盐因子的响应[J]. 北京林业大学学报, 2019, 41(10): 20�?9.

Zhong Y M, Wang W J, Wang J M, et al. Leaf functional traits of oasis plants in extremely arid areas and its response to soil water and salt factors[J]. Journal of Beijing Forestry University, 2019, 41(10): 20�?9. [48]安申�? 贡璐, 朱美�? �? 塔里木盆地北缘典型荒漠植物根系化学计量特征及其与土壤理化因子的关系[J]. 生态学�? 2017, 37(16): 5444�?450.

An S Q, Gong L, Zhu M L, et al. Root stoichiometric characteristics of desert plants and their correlation with soil physicochemical factors in the northern Tarim Basin[J]. Acta Ecologica Sinica, 2017, 37(16): 5444�?450. [49]Chaves M M, Flexas J, Pinheiro C. Photosynthesis under drought and salt stress: regulation mechanisms from whole plant to cell[J]. Annals of Botany, 2009, 103: 551�?60. doi:10.1093/aob/mcn125 [50]Niu D, Zhang C, Ma P, et al. Responses of leaf C∶N∶P stoichiometry to water supply in the desert shrub Zygophyllum xanthoxylum[J]. Plant Biology, 2019, 21: 82�?8. doi:10.1111/plb.12897 [51]Wang Z, Yu K, Lü S, et al. The scaling of fine root nitrogen versus phosphorus in terrestrial plants: a global synthesis[J]. Funct Ecol, 2019, 33: 2081�?094. doi:10.1111/1365-2435.13434 [52]Wang Y, Wang J M, Wang X L, et al. Dominant roles but distinct effects of groundwater depth on regulating leaf and fine-root N, P and N∶P ratios of plant communities[J]. Journal of Plant Ecology, 2021, 14(6): 1158�?174. doi:10.1093/jpe/rtab062 [53]Setia R, Gottschalk P, Smith P, et al. Soil salinity decreases global soil organic carbon stocks[J]. Science of the Total Environment, 2013, 465: 267�?72. doi:10.1016/j.scitotenv.2012.08.028 [54]Wang L L, Zhao G X, Li M, et al. C∶N∶P stoichiometry and leaf traits of halophytes in an arid saline environment, northwest China[J]. Plos One, 2015, 10(3): e0119935. doi:10.1371/journal.pone.0119935 [55]Sardans J, Peñuelas J. The role of plants in the effects of global change on nutrient availability and stoichiometry in the plant-soil system[J]. Plant Physiol, 2012, 160: 1741�?761. doi:10.1104/pp.112.208785 [56]张晓�? 周继�? 来利�? �? 黑河下游荒漠河岸地带土壤水盐和养分的空间分布特征[J]. 生态环境学�? 2019, 28(9): 1739�?747.

Zhang X L, Zhou J H, Lai L M, et al. Spatial characterization of soil water-salt and nutrient in a desert riparian area along the lower reaches of Heihe River, China[J]. Ecology and Environmental Sciences, 2019, 28(9): 1739�?747. [57]杨少�? 季静, 王罡. 盐胁迫对植物的影响及植物的抗盐机理[J]. 世界科技研究与发�? 2006(4): 70�?6. doi:10.3969/j.issn.1006-6055.2006.04.012

Yang S H, Ji J, Wang G. Effects of salt stress on plants and the mechanism of salt tolerance[J]. World Sci-Tech R & D, 2006(4): 70�?6. doi:10.3969/j.issn.1006-6055.2006.04.012 [58]Min W, Su Y, Xiao Y. Spatial distribution of soil organic carbon and its influencing factors in desert grasslands of the Hexi Corridor, northwest China[J]. Plos One, 2014: 9. doi:10.1371/journal.pone.0094652 [59]He M Z, Zhang K, Tan H J, et al. Nutrient levels within leaves, stems, and roots of the xeric species Reaumuria soongoricain relation to geographical, climatic, and soil conditions[J]. Ecology and Evolution, 2015, 5(7): 1494�?503. doi:10.1002/ece3.1441 [60]王健�? 董芳�? 巴海·那斯�? �? 中国黑戈壁植物多样性分布格局及其影响因素[J]. 生态学�? 2016, 36(12): 3488�?498.

Wang J M, Dong F Y, Bahai·Nasila, et al. Plant distribution patterns and the factors influencing plant diversity in the Black Gobi Desert of China[J]. Acta Ecologica Sinica, 2016, 36(12): 3488�?498.