刺槐叶片可塑生长的密度依赖性

为了探明刺槐叶片性状对种植密度的依赖性,通过刺槐田间栽培试验,研究了刺槐叶片可塑生长的密度依赖性以及主要叶片性状因子之间的关系.结果表明,不同种植密度条件下刺槐叶片厚度均无显著差异,但叶面积、叶绿素含蜃、叶片干重、比叶面积、叶干物质含量和叶片N含量差异显著,表明不同种植密度条件下刺槐叶性因子参数的变异较大,刺槐叶片性状对密度的依赖性较强.叶干重、叶厚度和叶片干物质含量均随种植密度的降低而呈增加趋势,叶片干物质含量与种植密度的相关性达到显著水平(P<0.01),而叶干重、叶厚度与种植密度的相关性不显著(P>0.05).比叶而积和叶片N含鼍均随种植密度的降低而降低,表明刺槐各叶性因子之间对种植密度的依赖性差异明显.对刺槐各叶性因子的相关分析表明,不同种植密度条件下各叶性因子之间的相关性及其强弱均存在差别,表明种植密度是影响刺槐叶性因子变异及叶性因子之间关系的因素之一.叶性特征对种植密度响应存在差异的主要原因是叶性因子之间的协同变化、刺槐生长微环境的差异和刺槐间竞争强度的差异,刺槐不同叶性因子之间的协调平衡和对种植密度响应程度与方向的差异表明了刺槐对其生长环境的适应.

Dependency between Plant Density and Leaf Growing Plasticity of Robinia pseudoacacia in Loess Plateau

Leaf traits have been identified as primary important in plant acquire,process and invest resources.Plant density can influence the leaf distribution,growth,and other traits through influence the plant growth,biomass distribution,matter transplant and furthermore influence the canopy characteristics.In order to clarify the dependency of plant leaf to the plant density,the patterns of leaf trait variation and trait correlations of Robinia pseudoacacia were investigated under different plant densities.The results indicated that there was no significant difference for leaf thickness under different plant densities.However,there were significant differences for the leaf area,leaf chlorophyll content,leaf dry weight,specific leaf area,leaf dry matter content and leaf nitrogen content under different plant densities,which showed leaf thickness and leaf dry matter content increased with the plant densities decreased,the correlation between leaf dry matter content and plant density was significantly different(P<0.01),but there were no significant correlations between leaf dry weight,leaf thickness and plant density(P>0.05).The specific leaf area and leaf nitrogen content decreased with the plant density decreased.The results indicated that the response of the leaf traits to plant densities was different from each other.The correlation analysis of the leaf traits indicated that the degree of the correlation between the different leaf traits was different,and the plant density was one of the factors that influence the leaf traits and leaf traits correlation.The main reasons for the differences in the response of Robinia pseudoacacia to plant density were the trait covariation,the difference of the microenvironment and the competition among individual plants under different plant density.The tradeoff among the leaf traits and the different response to the plant density imply that it is the adaptation strategy to the habitat.