邻体竞争和土壤对植物叶功能性状及其种内变异的影响

Effects of neighborhood competition and soil on plant leaf functional traits and their intraspecific variation

为探究亚热带幼树植物功能性状的种内变异与邻体竞争和土壤的关系,选取亚热带12个常见树种的幼树为研究对象,分析与植物资源获取、利用相关的6个叶功能性状(比叶面积、叶面积、叶干物质含量、叶片氮含量、叶片磷含量、叶厚度)的差异,探讨不同植物功能性状的种内变异程度及邻体竞争与土壤因素对其性状变化的影响。结果表明:6个叶功能性状的变异程度不同,其中比叶面积变异系数最大,变异范围16.71%~55.31%;叶干物质含量的种内变异系数最低。邻体竞争和土壤因素共同驱动叶功能性状的变化,但邻体竞争为主要驱动因素。邻体竞争指数与邻体高度指数对比叶面积和叶片磷含量有显著正影响(P<0.05),而叶面积和叶干物质含量仅随邻体高度指数的增大而显著减小或降低(P<0.05),叶片氮含量仅受土壤pH值的影响。此外,土壤含水量、土壤碳含量和土壤容重均会导致叶功能性状发生变化。因此,在营造人工林时,要充分考虑植物功能性状与环境适应的关系。

To investigate the relationship between intraspecific variation in plant functional traits and neighborhood competition and soil,young trees of 12 subtropical tree species were selected as research objects to analyze the differences in six common traits(specific leaf area,leaf area,leaf dry matter content,leaf nitrogen content,leaf phosphorus content,and leaf thickness)related to the acquisition and utilization of plant resources,to explore the degree of intraspecific variation in different plant functional traits,and the influence of neighborhood competitional and soil factors on the variation of these traits.The aim was to explore the degree of intraspecific variation in different plant functional traits and influence of neighborhood competitional and soil factors on these variations.The results showed that the six leaf traits exhibited different degrees of variability.Specific leaf area had the highest coefficient of variation,ranging from 16.71%to 55.31%,whereas leaf dry matter content had the lowest variability within the study species.Both neighborhood competition and soil factors influenced changes in leaf traits,with neighborhood competition playing a more significant role.Neighborhood competition index and neighborhood height index had significant positive effects on comparative leaf area and leaf phosphorus content(P<0.05).In contrast,leaf area and dry matter content significantly decreased with increasing neighborhood height index(P<0.05).Leaf nitrogen content was affected only by soil pH value.In addition,soil water content,soil carbon content,and soil bulk density contributed to variations in leaf traits.Therefore,when creating plantation forests,the relationship between plant functional traits and environmental adaptation should be considered.