水分梯度下干旱区湿地植物群落叶片养分重吸收及其影响机制研究

养分重吸收是多年生植物采取的关键养分利用策略，在植物适应不同养分浓度的环境中发挥重要作用，尤其在胁迫的环境中。养分重吸收格局具有区域和生态系统类型的依赖性特点，为进一步深入理解湿地生态系统养分重吸收的主要影响机制，项目以干旱区敦煌阳关湿地为研究对象，运用群落调查的野外定位监测、室内实验、数理统计及模型分析方法，分析湿地土壤水分变化下植物群落叶片的养分重吸收格局；探讨水分变化下湿地植物群落水平的叶片氮磷组分分配、植物不同器官养分分配的“源-库”关系对重吸收的影响、叶片氮磷重吸收与根系氮磷获取的权衡机制以及水分驱动下土壤（底泥）有效氮磷和矿化潜力的变化对重吸收影响的元素控制模式；甄别群落水平上叶片重吸收的关键影响因素，揭示水分梯度下干旱区湿地植物群落养分重吸收的影响机制。为理解水分驱动的土壤养分有效性变化下湿地植物的养分循环策略提供科学依据，对维护湿地生态系统的健康稳定具有重要的价值。

Nutrient resorption is a key nutrient utilization strategy adopted by perennial plants, which plays an important role in the adaptation of plants to different nutrient concentrations, especially in stress environment. The pattern of nutrient resorption is characterized by regional and ecosystem type. To elucidate the main effect and its mechanism of foliar nutrient resorption in wetland ecosystem, field location monitoring, lab-scale experiment, mathematical statistics and model analysis are used to uncover the foliar nutrient resorption pattern of plant community with soil moisture in the wetland ecosystem of Yangguan in Dunhuang of arid area. To identify the key influencing factor of foliar nutrient resorption at the level of plant community, the distribution of foliar nitrogen and phosphorus components, the "source-sink" relationship of nutrient distribution in different organs, the trade-off mechanism between the foliar resorption and the acquisition in the roots under the change of water content, and the elements control model under the change of soil (sediment) nitrogen and phosphorus available and mineralization potential driven by water content at the level of wetland plant community are explored. The mechanism of nutrient resorption of wetland plant community across soil moisture gradients was revealed. It provides a scientific basis for understanding the nutrient cycling strategy of wetland plants under the change of soil nutrient availability driven by water, and has an important value for maintaining the health and stability of wetland ecosystem.