缠绕植物手性的系统发育分析

Phylogenetic Development Analysis of Chirality of Twining Plants

利用matK、rbcL与trnL基因,分析了中国薯蓣属植物缠绕手性的系统发生关系;利用matK基因,从大分类单元角度进一步分析了缠绕植物的系统特征。结果显示左、右旋缠绕植物物种存在显著的系统发育特征:matK数据中的右旋薯蓣聚成独立的进化枝与rbcL基因的分析共同支持右旋物种的单系性;rbcL和trnL的数据均较好地显示了右旋薯蓣的单系特征[除多毛叶薯蓣(D.decipiens)和甘薯(D.esculenta)外];在大分类单元上,缠绕植物手性性状则呈现出明显的多系特征。结果表明在中国区薯蓣属的分类中,手性特征是较可靠的性状特征,《中国植物志》薯蓣属章节直接将右旋物种归入周生翅组(sect.Enantiophyllum)较合理。但在世界范围上看,在小分类单元的薯蓣属内和薯蓣科及其他大分类单元内,手性特征都具有单独多次起源的性质,因此在执行分类时应当慎用这个性状。对于手性特征的起源问题,最新的观点倾向于否定南北半球物理差异相关的假说,但其结论的正确性有待商榷。结合地质事件研究薯蓣属等具有两种手性方向的小分类单元,以及构建突变体的方法,有助于最终解决植物手性的起源问题。

Based on the genes matK,rbcL and trnL,the phylogenetic relationship of twining chirality of Dioscorea plants in China were analyzed.Using matK gene,the systematical characteristics of twining plants were further analyzed from the aspect of large taxon unit.The results showed that left-handed and right-handed species of twining plants had significant phylogenetic characteristics.Based on matK analysis,right-handed Dioscorea species in China congregated completely to form a monophyletic clade,which supported the monophyly of right-handed species on basis of the analysis of rbcL gene.The data of rbcL and trnL showed the monophyly characteristics of right-handed species.The chirality characters of twining plants showed obvious polyphyletic characteristics from the large taxon unit.The results indicated that chirality character was dependable in the classification of Dioscorea in China.It was reasonable that sort right-handed species was directly divided into sect.Enantiophyllum in ＇Flora of China＇.In the worldwide range,the chirality characters had the prosperities of single multiple sources in Dioscorea of small classification unit and other classification units.And it should be cautious to use this character.Latest evidences were inclined to refuse the hypothesis that twining direction was determined by latitude or hemisphere.However,the correctness of the conclusion needed to be discussed.Studying the small classification units such as Dioscorea with two kinds of chirality directions and the construction method of mutations on the basis of geological events were helpful to elucidate the origin problem of plant chirality.