入侵植物曼陀罗对本地植物功能性状和土壤碳、氮、磷化学计量特征的影响

为探讨不同入侵压力下入侵植物对本地植物功能性状土壤碳、氮、磷化学计量特征的影响，以入侵植物曼陀罗（Datura stramonium）及共存本地植物为研究对象，调查了无入侵区、轻度入侵区和重度入侵区（按入侵种盖度比例划分）的植物种类、株数、株高及本地植物群落的物种多样性，分析了各区入侵植物和本地植物叶片的比叶面积、碳含量、氮含量、碳氮比、叶片建成成本以及不同土层的碳、氮、磷化学计量特征。结果显示：随曼陀罗入侵压力的增加，本地植物种类及株数逐渐减少；曼陀罗株高和叶片氮含量在不同入侵压力下均显著高于本地植物，且随入侵压力的增加具有升高趋势；叶片碳氮比显著低于无入侵区本地植物；比叶面积、叶片碳含量和叶片建成成本等与入侵区本地植物相比不具有显著差异。随曼陀罗入侵压力的增加，土壤全氮含量、全碳含量、氮磷比与碳磷比显著增加，而全磷含量与碳氮比显著下降；土壤碳氮化学计量特征呈现出一定的表聚效应。这些研究结果表明，曼陀罗具有较高的资源捕获能力，并且改变了入侵地土壤特性，进而增强自身竞争能力以提高入侵力，这些可能是曼陀罗成功入侵的原因之一。

Effects of Invasive Plant Datura stramonium on the Functional Traits of Native Plants and the Stoichiometric Characteristics of Soil Carbon,Nitrogen and Phosphorus

The experiment was conducted to explore effects of invasive plants under the different pressures of invasion on the functional traits of native plants and the stoichiometric characteristics of soil carbon， nitrogen and phosphorus. We used invasive plant Datura stramonium and coexisting native plants as the research object， researches species， number and height of plants in sample plots and the species diversity of native plant communities with no invasion， low invasion and heavy invasion（according to the proportion of invasive plants coverage）， and analyzed the specific leaf area， carbon content， nitrogen content， carbon to nitrogen ratio， leaf construction cost and carbon， nitrogen and phosphorus stoichiometric characteristics in different soil layers. With the increase of invasion pressure， the species richness and the number of native plants decreased gradually. The plant height and leaf nitrogen content of D.stramonium were significantly higher than that of native plants under different invasion pressures， and gradually increased with the increase of invasion pressure. The carbon to nitrogen ratio was significantly lower than that of native plants in sample plots with no invasion. The specific leaf area， carbon content and leaf construction cost were not significantly different from those of native plants in sample plots with invasion. With the increase of invasion pressure， soil total nitrogen content， total carbon content， nitrogen to phosphorus ratio and carbon to phosphorus ratio increased significantly， while total phosphorus content and carbon to nitrogen ratio decreased significantly. Soil carbon and nitrogen stoichiometric characteristics show a certain surface clustering effect. These results show that D.stramonium has a high resource capture ability， and has changed the characteristics of soil， so as to enhance its own competitiveness to improve the invasion ability， which may be one of the reasons for the successful invasion of D.stramonium.