沙芥属(十字花科)的起源、分类与进化研究进展

Review on the Origin,Taxonomy and Evolution of Pugionium Species (Brassicaceae)

沙芥属(PugioniumGaertn.)最初是从匙荠属(Bunias)中分出来单独建立的属,ndhF系统树表明,该属和高河菜属(Megacarpaea)、Farsetia、香雪球属(Lobularia)、屈曲花属(Iberis)和Ionopsidium亲缘关系较近,且和高河菜属构成姐妹关系。自从沙芥属确立以来,先后发表过沙芥[P.cornutum(L.)Gaertn]、斧形沙芥(P.dolabratum Maxim.)、距果沙芥(P.calcaratum Kom.)、鸡冠沙芥(P.cristatum Kom.)、翅果沙芥(P.pterocarpum Kom.)等5个种和宽翅沙芥(P.dolabratumvar.platypterum H.L.Yang)1个变种,但形态统计学和分子生物学的证据表明,沙芥属应该仅包含沙芥(P.cornutum)和斧形沙芥(P.dolabratum)2个形态学物种。基于不同遗传背景的DNA分子标记的研究结果进一步表明,沙芥和斧形沙芥这2个形态学物种间的遗传分化明显,但种间分化的时间并不久远,它们很可能是更新世以来随中亚和中国西北沙漠发展扩张而形成的2个近期分化的姐妹种。该文对沙芥属的系统起源、属下分类和遗传进化方面的研究历史和最新研究进展进行综述,并提出了研究中存在的问题。

Pugionium Gaertn.was originally separated from the genus Bunias,and the phylogenetic tree based on ndhF sequences suggested that Pugioniumis sister to Megacarpaeaand,together they are closely related to Farsetia,Lobularia,Iberis and Ionopsidium.Since the establishment of Pugionium,a total of five species and one variety（i.e.P.cornutum（L.）Gaertn,P.dolabratum Maxim.,P.calcaratum Kom.,P.cristatum Kom.,P.pterocarpum Kom.and P.dolabratumvar.platypterum H.L.Yang）have been described under this genus.However,the morphologically statistical methods and molecular evidence showed that only two morphological species,namely P.dolabratumand P.cornutum,can be warranted.Furthermore,the results based on different DNA markers with contrasting genetic surroundings suggested that the genetic divergences between these two morphological species are very distinct,although the interspecific differentiation time is not too long.It is highly likely that the two sister species of Pugioniumdiverged within the recent Pleistocene in association with the expansion of deserts in central Asia and northern Chi-na.In this paper,we reviewed the research history and latest progress on the phylogenetic origin,classification,genetic evolution of the genus Pugionium Gaertn.,and put forward to some problems,inspirations and prospects on the studies of this genus.