濒危植物水青树叶的表型性状变异

Leaf Phenotypic Traits of Tetracentron sinense,an Endangered Plant Species

[目的]通过对濒危植物水青树叶表型性状的测量分析,研究其表型变异程度和变异规律,并从遗传和环境适应角度探讨其致濒机制,为其天然种群的有效保护及管理提供科学依据。[方法]对来自14个水青树天然种群的90个个体的17个叶形态及其表皮微形态性状进行测量,利用巢式方差分析、多重比较、主成分分析、聚类分析、相关分析等多种分析方法,探讨种群间和种群内的叶表型变异及其与地理、环境因子的相关性。[结果](1)水青树17个叶表型性状在种群内和种群间均存在显著差异;(2)17个性状的平均表型分化系数为46.69%,种群内的变异(31.83%)大于种群间的变异(28.85%),种群内变异是水青树叶表型变异的主要来源;(3)各性状平均变异系数(CV)为12.56%,变异幅度为4.17%26.25%;(4)水青树叶表型变异与年均日照时数、7月均温及年均降雨量等环境因子有关,变异呈现出随经度、纬度、海拔的梯度渐变规律;(5)利用主成分分析结果进一步聚类,可将14个水青树天然种群分为3大类。[结论]水青树天然种群间叶表型分化处于中等水平,种群内变异程度较低,其对环境的适应范围缩减,适应能力较差,这可能是导致水青树濒危的重要原因。据此,提出了相应的保护措施以便对其进行有效保护。

[ Objective] The leaf phenotypie traits of understand the phenotypic variation. The purpose is to endangered plant Tetracentron sinense were measured to discuss the mechanism causing its endangering from the perspective of genetics and the ability to adapt to hostile conditions in order to provide some references for effective conservation and management. [ Method ] Seventeen leaf morphological characteristics and leaf epidermis micro- morphological characteristics from 90 individuals of fourteen populations were measured. Nested analysis of vari- ance, multi-comparison, principal components analysis, cluster analysis, and correlation analysis were used to study the leaf phenotypic variation and its relation to environmental factors. [ Result ] （ 1 ） Analysis of nested variance for all the traits showed significant differences among and within populations. （2） The mean phenotypic dif- ferentiation coefficient for all the traits was 46.69%, and the variation within populations （31.83 % ） was higher than that among populations （28.85%） , indicating that the variance within population is the main source of the phenotypic variation of the species. （3） The range of variation of coefficient of variance among the 17 traits was 4.17 % - 26.25 % , and the average was 12.56%. （4） The leaf phenotypic variation of T. Sinense was related to the environmental factors, such as mean annual sunshine duration, mean temperature in July, and mean annual precipitation. The gradient rule of leaf phenotypic characteristics is presented along with longitude, latitude and altitude. （5） According to the cluster analysis based on the results of principal components analysis, the 14 natu- ral populations of T. sinense could be divided into three groups. [ Conclusion ] There were moderate level of phe- notypic differentiation among populations and low level of phenotypic variation within populations. The decreasing distribution range and poorer adaptability to changing environment were the main factors influencing the survival of T. sinense. According to above conclusions, some corresponding conservation measures were proposed to protect natural populations of T. sinense.