土壤养分变化对鄱阳湖湿地植物叶片氮磷及其化学计量关系的影响

Effects of soil nutrients on leaf N,P and N ∶ P stoichiometry in Poyang Lake wetlands

在鄱阳湖湿地典型分布区采集常见植物的叶片与根际土壤样品,以探讨土壤养分变化对湿地植物叶片氮磷含量及其化学计量关系的影响。结果表明:鄱阳湖湿地植物叶N含量变化范围为4.98~52.29 g·kg^(-1),平均值为(21.71±8.99) g·kg^(-1);叶P含量波动范围为0.44~3.02 g·kg^(-1),平均值为(1.38±0.53) g·kg^(-1); N∶P平均值为(17.19±8.23);叶片N、P含量受土壤P含量的影响显著,对土壤P含量的变化较N更敏感;叶片N∶P化学计量关系具有稳定性特征,不随土壤N、P养分变化而产生显著差异,且叶片N-P线性关系在不同土壤养分环境下没有发生策略位移现象。

To examine the effects of soil nutrients on leaf nitrogen（ N）,and phosphorus（ P）,and N ∶ P stoichiometry in Poyang Lake wetlands,we collected leaf and rhizospheric soil samples and analyzed N and P concentrations. Results showed that leaf N concentration ranged from 0.44 to 3.02 g·kg^-1,with an average of 21.71±8.99 g·kg^-1. Leaf P concentration varied from 0.44 to 3.02 g·kg^-1,with an average of 1.38±0.53 g·kg^-1. The mean of foliar N ∶ P ratio was 17.19±8.23,suggesting that P,rather than N availability,mainly limited plant growth in Poyang Lake wetlands. Moreover,leaf N and P concentrations were more sensitive to changes in soil P availability rather than soil N availability. Leaf N ∶ P stoichiometry was well constrained in Poyang Lake wetlands,in that variation in soil N and P did not alter foliar N ∶ P. In addition,the significantly positive correlations between leaf N and P concentrations were found in various soil nutrient environments. The relationship between N and P in leaves did not shift with the changes of soil nutrients.