桂林喀斯特石山不同坡向乔灌木功能性状对比研究

植物功能性状是连接植物与环境的桥梁,能够客观表达植物对不同生长环境的响应,研究植物功能性状特征及其随坡向的变化规律,对认识不同环境梯度下植物群落的形成过程及其对环境的适应机制具有重要意义。以桂林喀斯特石山不同坡向乔、灌木为研究对象,对比分析不同坡向灌丛植物功能性状在营养性状(生长型、生活习性、比叶面积、叶干物质含量、叶片厚度、叶组织密度)和生理性状(叶绿素含量)上的差异,探究喀斯特石山植被对不同坡向微气候生境的适应策略。结果表明:阴坡的灌木和耐阴物种数多于阳坡,比叶面积、叶绿素含量的群落加权平均值为阴坡大于阳坡;阳坡的乔木物种数多于阴坡,叶干物质含量、叶厚度和叶组织密度的群落加权平均值也均为阳坡大于阴坡。植物营养性状(叶片厚度和叶组织密度)为喀斯特石山不同坡向植物群落差异显著的主要功能性状。植物功能性状随坡向的规律性变化,反映了喀斯特石山灌丛群落构建过程中环境对植被的筛选效应。

Comparative Study on Functional Traits of Trees and Shrubs in Different Slope Aspects on Karst Hills of Guilin

Plant functional traits are a bridge that connects plants to the environment, which can objectively express the response of plants to different growth environments. Studying the characteristics of plant functional traits and their changes with slope aspects is of great significance for understanding the process of plant community formation and its adaptation mechanism to the environment under different environmental gradients. Taking trees and shrubs in different slopes of karst hills of Guilin as the research object, the differences in functional traits (growth type, living habits, specific leaf area, leaf dry matter content, leaf thickness, leaf tissue density) and physiological traits (chlorophyll content) of plants in different slope shrubs were comparatively analyzed to explore the adaptation strategies of karst hills vegetation to different slope microclimate habitats. The results showed that the number of shrubs and shade-tolerant species on the shady slope was more than that of the sunny slope, and the community-weighted average of the specific leaf area and chlorophyll content on shady slope was greater than that on sunny slope. The number of tree species on sunny slope was more than that on shady slope. The community-weighted average of leaf dry matter content, leaf thickness, and leaf tissue density on shady slope was also greater than those on sunny slope. Plant nutritional traits (leaf thickness and leaf tissue density) are the main functional traits which have significant differences among different slope plant communities in karst hills. The regular changes of plant functional traits with slope aspect reflect the screening effect of environment on vegetation during the construction of shrub communities in karst hills.