【摘要】 氮(N)、磷(P)作为荒漠生态系统重要的养分元素和限制性因子,在维持植物功能群组成及结构稳定、生态系统内养分循环中发挥着重要的作用。本研究沿水热梯度从东至西在阿拉善荒漠设置52个调查样地,通过对优势植物的调查取样,分析了荒漠植物不同功能(类)群N、P元素的生态化学计量特征,并就N、P含量及N∶P值对荒漠植物的限制性作用进行了检验和讨论。结果显示:(1)所调查阿拉善荒漠区植物叶片的N、P含量分别为10.65±7.91mg·g-1和1.04±0.81mg·g-1,N∶P值为11.53±5.06,叶片N含量与P含量及N∶P值均显著正相关,P含量与N∶P值显著负相关;通过对比分析认为该区植物同时受到N、P双重制约,且更易受N限制。(2)从植物生活型比较,认为草本植物叶片N、P含量均高于灌木植物叶片,而灌木植物叶片的N∶P值大于草本植物;对光合作用途径分析发现,C3植物叶片N含量高于C4植物叶片,而C4植物叶片P含量高于C3植物叶片;从系统发育类型方面分析,认为单子叶植物叶片N含量低于双子叶植物叶片N含量,而P含量则高于双子叶植物叶片P含量。更多还原

【Abstract】 Nitrogen and phosphorus are crucial limiting factors of nutrient elements in desert ecosystem,which play vital roles in maintaining the rational composition of plant functional groups and driving the nutrient cycling of the desert ecosystem.By sampling the dominant plant leaves among the 52 sample sites that be set along the precipitation and temperature gradients from the eastern to western in Alashan desert,ecological stoichiometric characteristics of nitrogen and phosphorus among different plant functional groups were analyzed and the restrictive effects of N and P on the desert plants were tested and discussed.The results showed that(1)Leaf N and P concentrations were(10.65±7.91)mg·g-1and(1.04±0.81)mg·g-1,respectively,while N∶P was(11.53±5.06).Leaf nitrogen has significantly positive correlation with N and N∶P ratio and leaf P has significantly negative correlation with N∶P ratio.By comparison and analysis,desert plants were co-limited by N and P,and were more limited by N.(2)Generally,from the comparison of plant life types,leaf N and P content in herbaceous plants were higher than those in shrubs and N∶P in shrubs was greater than in herbs.From the analysis of photosynthetic pathway,C3 plants had higher average N concentration than C4 plants,while C4 plants had higher average P concentration than C3 plants.From the type of phylogenetic,leaf N content was lower in monocotyledons than in dicotyledons while P content was higher in monocotyledons than in dicotyledons.更多还原