太白杜鹃天然居群的表型多样性

Phenotypic Variation of Natural Populations in Rhododendron purdomii in Qinling Mountains

为揭示太白杜鹃(Rhododendron purdomii)天然居群的表型变异程度、变异规律,以秦岭山区的7个天然居群为研究对象,对其花序和叶片的10个数量性状和8个质量性状进行方差分析、相关分析与聚类分析,探讨居群间与居群内表型多样性的变异特点。结果显示:(1)在太白杜鹃的质量性状中,花色与花瓣内斑在居群间与居群内均存在丰富变异,花朵香味、花序形状、花冠形状、花梗颜色、叶片形状和株型等仅在居群间存在明显变异,在居群内则趋于一致性;其数量性状在居群间与居群内也存在广泛变异,10个数量性状在居群间和居群内平均值差异全部达显著水平;在7个居群内数量性状的变异系数为0～55.3%,其中花梗长、花丝长、花瓣宽与叶柄长变异较大,花朵数变异较小。(2)相关性分析表明,太白杜鹃花瓣长和花瓣宽分别与经度存在极显著与显著负相关关系,叶片长、叶片宽和叶片长宽比与海拔均存在显著负相关关系,而其它性状与地理因子的关系密切。(3)聚类分析显示,太白杜鹃的7个天然居群可以初步分为两大类,但性状的表型特征并没有依地理距离而聚类。研究表明,太白杜鹃天然居群的表型性状在居群内与居群间均存在丰富的变异,而且其与居群特点、分布生境等关系密切。

Our experiment was conducted to investigate phenotypic variation of Rhododendron purdomii in 7 natural populations and to discuss the relationship between phenotypic variation of the natural population and different distribution areas. We investigated 10 quantitative traits and 8 qualitative traits in 7 natural populations of R. purdornii from Qinling Mountains in Shaanxi Province of China and used multi-comparison, correlation analysis and cluster analysis to analyze results. Analysis showed that ： （1） The flower color and spots in petal were significantly different in and among populations,while the other traits were significantly different only among populations,and similar in populations for qualitative traits. In 10 quantitative traits, differences of the mean of every quantitative trait were all significantly different in and among popu- lations. The coefficient of variation of quantitative traits was from 0 to 55. 3% in populations. Among these, pedicels length, filament length, petal width and petiole length varied more, and the number of flower varied less. （2）The correlation analysis between the phenotypic traits of R. purdomii and geography factor showed that the correlation between them were not significant except that length and width of petal weresignificantly negative affected by latitude,while length and width of leaf and aspect ratio were significantly negative affected by elevation. （3）Cluster analysis showed that seven natural populations of R. purdomii could be divided into 2 groups by SPSS cluster analysis. Explaining the phenotypic traits did not gather ac- cording to geography distance. In summary, the phcnotypic characteristics of R. purdomii had rich variation in and among populations. And they were relevant to population characteristics and habitat. These provided references to further study the population ecosystem,conservation and utilization of R. purdomii.