古尔班通古特沙漠水热梯度变化对短命植物生态化学计量特征影响

以古尔班通古特沙漠2种优势短命植物尖喙牻牛儿苗(Erodium oxyrhinchum M. Bieb.)和东方旱麦草(Eremopyrum orientale (L.) Jaubert & Spach)为研究对象，通过盆栽控制实验，设定2个温度梯度以及3个水分梯度，对它们在不同温、湿度处理下的C、N、P含量及其化学计量比的变化特点进行分析。结果显示：(1)温度显著影响尖喙牻牛儿苗的N、P、C∶P、N∶P以及东方旱麦草的C、N、P、C∶N、N∶P；水分显著影响2种短命植物的N、P、C∶N、C∶P以及东方旱麦草的N∶P，其中N含量随温度的变化符合温度-生物地球化学假说，而P含量随温度的变化符合温度-植物生理假说。(2)温度和水分的交互作用对2种植物的影响表现为：在高温处理时，随着水分梯度的增加，2种植物的N、P含量先升高再下降，C∶N、C∶P、N∶P先下降再升高；在低温处理时，尖喙牻牛儿苗的N、P含量变化与水分梯度呈反比，C∶P变化与水分梯度呈正比，而东方旱麦草化学计量变化差异不显著。(3)相关性分析结果表明，温度和水分显著影响2种短命植物各元素之间的相关关系，植物的生长速率和养分限制情况受营养元素的主导调控也随之变化。

Changes in ecological stoichiometry of two ephemeral plants with a hydrothermal gradient in the Gurbantünggüt Desert

Two dominant ephemeral plants, i.e., Erodium oxyrhinchum M. Bieb. and Eremopyrum orientale (L.) Jaubert & Spach, from the Gurbantünggüt Desert were used for potted plant experiments under controlled conditions. We set two temperature gradients and three moisture gradients to analyze variation characteristics in carbon (C), nitrogen (N), and phosphorus (P) contents and their stoichiometric ratios under different temperature and humidity treatments. Results show that: (1) Temperature significantly affected N, P contents, C∶P, and N∶P in Erodium oxyrhinchum, and C, N, P, C∶N, and N∶P in Eremopyrum orientale. Water significantly affected N, P, C∶N, and C∶P in both plants and N∶P in Eremopyrum orientale. The changes in N content with temperature conformed to the temperature-biogeochemical hypothesis, while the changes in P content with temperature conformed to the temperature-plant physiology hypothesis. (2) Interactions between temperature and water also affected the plants. Under high temperature treatment, as the water gradient increased, N and P contents in both plants first increased and then decreased, while C∶N, C∶P, and N∶P first decreased and then increased. Under low temperature treatment, changes in N and P contents in Erodium oxyrhinchum were inversely proportional to the water gradient, while changes in C∶P were directly proportional to the water gradient. However, the stoichiometric changes in Eremopyrum orientale were not significant. (3) Correlation analysis showed that temperature and water significantly affected element correlations in both plants, and the growth rates and nutrient limitations of the plants were also subject to dominant regulation of the nutrient elements.