闽江福州段湿地草本植物叶片与细根功能性状对水盐梯度的响应

Responses of leaf and fine root functional traits to water-salt gradients in the Fuzhou section of the Minjiang River Basin

叶片和细根是植物获取资源最重要的器官,探究叶片、细根功能性状之间的相互关系及其对环境梯度变化的响应,有利于揭示植物对资源的利用情况以及对环境变化适应的生态策略。本文以湿地草本植物为研究对象,闽江流域福州段4个典型湿地为研究区域,设置了3条垂直于河道的调查样带,108个样方,选取7个叶功能性状以及5个细根功能性状指标,运用单因素方差分析、相关性分析、冗余分析等方法分析湿地草本植物叶片与细根功能性状对水盐梯度的响应。结果显示:(1)叶形指数和根组织密度变异系数最大;(2)叶厚、叶干物质含量、根体积、比根长随着水盐条件的增加而增加,比叶面积和根组织密度则随着水盐条件的增加而减小,冗余分析表明土壤含水量的影响更为关键;(3)比叶面积与叶面积、叶厚等呈极显著负相关;叶组织密度和叶干物质含量均与比根长、比根面积均呈极显著正相关;(4)地上和地下部分的功能性状在不同的水盐梯度下,一部分成对性状会呈现协同一致的趋势。研究结果说明,湿地草本植物对于水盐条件变化的适应能够通过叶、细根功能性状的相互调节而实现,具有较强的性状可塑性。

Leaves and fine roots are the most important organs for plant resource acquisition.Exploring the relationship between their functional traits and responses to environmental gradients can reflect the adaptive strategies of plants to cope with environmental change.Here,we examined wetland herbage in the Fuzhou section of the Minjiang River Basin,establishing three belts and 108 quadrats across four typical wetlands,and selected seven leaf functional traits and five fine root functional traits to analyze their responses to water and salt gradients using single-factor analysis of variance,correlation analysis,and redundancy analysis.Results showed that the coefficients of variation for leaf index and root tissue density were notably high.Leaf thickness,leaf dry matter content,root volume,and specific root length increased with increasing water and salt content,while specific leaf area and root tissue density decreased.Redundancy analysis showed that soil water content was the most significant.Leaf area was negatively correlated with leaf thickness,leaf area.Leaf tissue density,and leaf dry matter content were positively correlated with specific root length and specific root area.Under different water and salt gradients,the functional traits of the above-ground and below-ground parts showed a synergistic trend.Overall,this study revealed the leaves and fine roots trait dynamics of wetland herbaceous plants under varying water-salt conditions,enhancing our understanding of their response mechanisms to water-salt gradients as well as wetland plant resource acquisition and adaptation strategies in southeast China.