中文摘要：

通过研究不同光照和氮素营养处理的外来植物凤眼莲的生长、生物量分配、硝酸还原酶活性、游离氨基酸以及可溶性蛋白质含量变化，探讨其对环境适应性的生理学机制。凤眼莲表现出极强的可塑性，随光照和氮素营养的增加，凤眼莲生长速率明显加快，氮素代谢关键酶硝酸还原酶活性上升。根部吸收的硝酸根离子大部分运输到叶片中还原，氮素同化效率高。氨基酸含量和可溶性蛋白质含量呈现明显的变化，叶片可溶性蛋白质含量与根冠生物量分配显著相关。本研究表明风眼莲对光照和氮素表现出很强的适应性，其快速生长和高可塑性依赖于对环境变化的牛理响廊。

英文摘要：

Changes of growth,biomass allocation,nitrate reductase activity,free amino acids, and soluble protein contents in Eichhornia crassipes （Mart.） Solms were studied under different irradiance and nitrate conditions in order to understand physiological mechanisms of adaptability to environment. Our results indicated that E. crassipes displayed strong phenotypic plasticity response to varied light and nitrate. Relative growth rate, nitrate reductase activity were significantly increased with increased irradiance and supplied nitrate. Majority of nitrate was reduced in leaves,and E. crassipes have the capability of utilizing nitrate efficiently. Contents of free amino acids and soluble protein varied with the changes of irradiance and supplied nitrate,and there was significantly correlation between leaf soluble protein content and biomass allocation. This study suggested that E. crassipes displays strong adaptability to irradiance and nitrate availability,and its fast growth and high plasticity depended on its physiological response to environment.