密度制约下尕海湿地黄帚橐吾叶绿素与叶面积、叶厚度间的关系

The relationship between chlorophyll and leaf area,leaf thickness of Liguaria virgaurea under density-dependent condition in Gahai wetland

密度制约下植物叶性状间的关系,对于认识植物叶片的物理构建与生理代谢的关系具有重要的意义。本研究采用标准化主轴估计分析方法,按黄帚橐吾(Liguaria virgaurea)种群数设置I(171～240株·m^(-2))、II(101～170株·m^(-2))和III(30～100株·m^(-2))3个密度,分析了尕海湿地不同种群密度黄帚橐吾叶绿素含量与叶面积、叶厚度的关系。结果表明:随着黄帚橐吾种群密度的降低,湿地群落的密度呈先减小后增大的U型趋势、盖度逐渐降低、高度和土壤水分逐渐增加,黄帚橐吾的叶面积和叶绿素含量逐渐增加、叶厚度和群落内部光合有效辐射逐渐减小、净光合速率和蒸腾速率呈先减小后增大的U型趋势;叶绿素含量与叶面积呈显著负相关(P<0.05)、与叶厚度呈显著正相关(P<0.05)。生长在高密度湿地的黄帚橐吾选择增加叶绿素含量且构建小而厚的叶片,在低密度湿地选择减少叶绿素含量且构建大而薄的叶片,反映了植物适应光照条件等异质性环境因子的资源利用策略和光合产物积累模式。

The relationships among leaf traits under different densities are important for under- standing the relationship between the physical construction and physiological metabolism of plant leaves.We examined the relationship between chlorophyll content and leaf area,leaf thickness of Liguaria virgaurea with different population densities in Gahai alpine wetland.The L.virgaurea populations were divided into three densities i high (I,171-240bundles ·m^-2),medium (II, 101-170bundles·m^-2)and low (III,30-100bundles·m^-2).Three plots (1mxl m)were established for each density to investigate plant leaf traits.The estimation analysis of standardized major axis and Pearson correlation analysis were used to examine the allometric relationship between chlorophyll content and leaf area and thickness.The results showed that,with decreasing density of L.virgaurea population,density displayed a decrease-increase trend,vegetation cover- age decreased,while plant height and soil moisture increased.Leaf area and chlorophyll content decreased gradually,and leaf thickness and specific photosynthetically active radiation inside the community decreased gradually.Moreover,leaf.net photosynthetic rate and transpiration rate dis- played a decrease-increase trend.Chlorophyll content was significantly negatively correlated with leaf area (P<O.05)but positively correlated with leaf thickness (P<O.05).Our results indicated that L.virgaurea growing in high-density wetland has high chlorophyll content but small and thick leaves,whereas that growinz in low-densitv wetland has low chloronhvll content but bit and thin leaves.Our results reflect the adaptation of resource use strategies and photosynthetic product ac- cumulation pattern of plants to the heterogeneity of environmental factors such as light conditions.