桂林岩溶石山青冈群落主要木本植物功能性状变异与关联

研究植物功能性状变异以及不同性状之间的关系, 有助于了解植物对环境的适应策略, 对揭示群落构建和生物多样性维持机制具有重要意义。本研究以桂林岩溶石山青冈群落18种主要木本植物为研究对象, 采用单因素方差分析、混合线性模型以及Pearson相关分析和主成分分析等方法探讨了不同生长型和生活型物种的9个枝、叶功能性状(叶绿素含量、叶片厚度、叶面积、叶干质量、比叶面积、叶干物质含量、叶组织密度、小枝干物质含量和小枝组织密度)的变异与关联。结果表明: (1) 9个功能性状的变异程度不同, 叶面积和叶干质量的种内和种间变异系数最大, 小枝干物质含量和小枝组织密度的种内和种间变异系数最小。(2)在生长型水平上, 乔木、灌木和木质藤本的绝大部分功能性状差异显著。(3)对于不同生活型植物, 除叶面积和比叶面积为落叶植物显著大于常绿植物外, 其余7个功能性状皆为常绿植物显著大于落叶植物。(4)不同生长型和生活型植物功能性状的种内和种间变异大小存在差异, 除部分植物功能性状在一些功能型上表现为种内变异高于种间变异, 其余功能性状的种间变异皆高于种内变异。(5)各功能性状之间关系在个体水平和物种水平大致相同, 但是个体水平上的显著相关比例高于物种水平。研究发现, 植物功能性状的种间变异基本高于种内变异, 但种内变异不容忽略。此外, 不同生长型和生活型物种采取不同的生态策略来适应喀斯特生境。今后的研究应基于个体水平采样并结合环境因子从生长型和生活型等不同功能型角度上深入探究植物功能性状在种内和种间等不同尺度上的变异与关联。

Variation and correlation in functional traits of main woody plants in the Cyclobalanopsis glauca community in the karst hills of Guilin,southwest China

Aims Exploring the variation and the relationship between different functional traits of different growth forms and life forms woody species is helpful to understand the adaptation strategies of plants to the external environment, and is of great significance for understanding community assembly and biodiversity maintenance mechanisms.Methods We measured leaf chlorophyll content (CHL), leaf thickness (LTH), leaf area (LA), leaf dry mass (LDM), specific leaf area (SLA), leaf dry matter content (LDMC), leaf tissue density (LTD), twig dry matter content (TDMC) and twig tissue density (TTD) of 18 main woody species from the Cyclobalanopsis glauca community in karst hills of Guilin, southwest China. Traits variations among different plant functional types (growth form and life form) of woody species were analyzed by a series of methods, including the one-way analysis of variance (one-way ANOVA), and the linear mixed-effects model. In addition, the relationships between nine functional traits on individual and species levels were assessed by the Pearson’s correlation test and principal component analysis (PCA).Important findings The results showed that: (1) The nine functional traits had different degrees of variation. Specifically, LA and LDM had the maximum coefficient of intraspecific and interspecific variation, while the intraspecific and interspecific variation coefficients of TDMC and TTD were the lowest. (2) For different growth forms, there were significant differences in most functional traits between trees, shrubs and woody lianas. (3) For different life forms, except that the deciduous species showed significantly higher LA and SLA values than evergreen species, and for the other seven functional traits, evergreen species showed significantly higher values than those of deciduous species. (4) There were differences in the intraspecific and interspecific variation of functional traits between different growth forms and life forms plants. Except for some plant functional traits showing the intraspecific variation higher than interspecific variation, most of the other functional traits showed the interspecific variation was higher than intraspecific variation. (5) The relationships between nine functional traits are roughly the same at the individual level and the species level, while the significant correlation ratio at the individual level is higher than the species level. In conclusion, the interspecific variation of plant functional traits is basically higher than the intraspecific variation, but the intraspecific variation cannot be ignored. In addition, species with different growth forms and life forms adopt different ecological strategies to adapt to the karst habitat. Future research should be based on sampling at the individual level, and in combination with environmental factors to explore the variation and correlation in functional traits of different plant functional types at different scales.