生物多样性 ›› 2005, Vol. 13 ›› Issue (5): 376-386.doi: 10.1360/biodiv.050070

所属专题: 探索长江流域物种的濒危机制

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濒危植物独花兰的形态变异及其适应意义

孙海芹, 李昂, 班玮, 郑晓明, 葛颂*   

  1. 中国科学院植物研究所系统与进化植物学重点实验室, 北京 100093
  • 收稿日期:2005-03-15 修回日期:2005-04-19 出版日期:2005-09-20
  • 通讯作者: 葛 颂

Morphological variation and its adaptive significance for Changnienia amoena, an endangered orchid

Haiqin Sun, Ang Li, Wei Ban, Xiaoming Zheng, Song Ge*   

  1. Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
  • Received:2005-03-15 Revised:2005-04-19 Online:2005-09-20
  • Contact: Song Ge

采用ANOVA和UPGMA等方法对濒危植物独花兰(Changnienia amoena)分布于庐山、新宁和神农架3个地点的12个自然居群的形态变异进行了研究, 探讨其形态多样性水平和地理变异式样及其可能的适应机制。结果表明, 庐山居群13个性状的平均观测值均高于新宁和神农架居群。在物种水平上各个性状存在较丰富的变异, 变异系数(CV值)为0.02–0.30。尽管同一性状在不同居群中的变异程度较大, 但总体而言, 花部器官的变异性比营养器官低。单因素方差分析显示3个地区间多个形态性状存在极显著差异(P<0.01); UPGMA聚类分析也表明这3个地区分别形成明显不同的分支。值得注意的是, 神农架地区龙门河和关门山两个地点间存在明显的形态分化, 而这种形态分化是以传粉者为媒介自然选择的结果。相关性分析显示, 营养器官之间、花部器官之间, 以及营养器官与花部器官之间均存在较高的相关性。上述结果对进一步了解独花兰的适应机制以及制定科学的保护策略提供了有益的资料。

Investigation of intraspecific morphological variation is critical for the understanding of evolutionary and ecological processes, and may provide insights for uncovering the roles of natural selection, gene flow, and genetic drift in the distribution and abundance of species diversity. In the present study, we analyzed statistically the patterns of variation of 13 morphological traits among 12 populations in three localities of an endemic orchid, Changnienia amoena. The results showed that, among the three localities, the mean value of all measured morphological traits is the highest in the Lushan populations. There is abundant variation at both the species and population levels. Coefficient of variation (CV) varied between 0.02 and 0.30 at the species level, and the CV values of reproductive organs were lower than those of vegetative structures. ANOVA analysis showed that there was significant difference in most morphological traits among the three localities. UP-GMA analysis showed that the populations in three localities were clustered into three main clades, the populations from Xinning and Lushan formed one clade, while the Shennongjia populations formed another clade. It is noteworthy that the Shennongjia populations were separated into two subclades corresponding to the populations at Longmenhe and Guanmenshan, respectively. This morphological differentiation is most likely a result of pollinator-mediated selection because this species is pollinated by different bumblebee species at these two sites. Pearson correlation analysis showed that high correlation occurred within the vegetative organs, reproductive organs, and be-tween them. These results have important implications for our understanding of the evolutionary processes and mechanism of C. amoena and might provide useful information for the conservation and management of this endangered orchid.

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