杉科的染色体资料及在系统演化研究中的作用

THE CHROMOSOME DATA AND ITS ROLE IN STUDY ON SYSTEMATIC EVOLUTION OF TAXODIACEAE

杉科共由10属(包括金松属)、20种(变种)组成。本文整理了19种(占95％,隶10属)植物的染色体数目和16种(占80％,隶9属)的核型资料,核型的模式图如图1所示。通过对这些细胞学资料的分析,笔者支持2n=20、x=10的金松属从杉科(2n=22、x=11)分立成金松科。根据其他各属间的亲缘关系,本作者认为可以把它们分隶于5个亚科:Ⅰ.柳杉亚科:Cryptomerioideae(Cryptomeria);Ⅱ.落羽杉亚科Taxodioideae(Glyptostroous,Taxodium);Ⅲ.红杉亚科Sequoideae(Metasequoia,Sequoiadendron,Sequoia);Ⅳ.杉木亚科Cunninghamioideae(Cunninghamia,还可能有:Athrotaxis);Ⅴ.台湾杉亚科Taiwainoideae(Taiwania)。这些亚科和属的进化水平依序渐增,它们分别位于进化路线A(亚科Ⅰ、Ⅱ、Ⅴ)和进化路线L(亚科Ⅲ、Ⅳ)上。这些结果是前人的演化系统所没有涉及的,表明了染色体资料在杉科的系统演化研究中起着重要的作用。

Taxodiaceae consists of 10 genera (incl. Sciadopitys) and 20 species (varieties) in all. The present paper consolidates the information on the chromosome numbers of 19 species ( 95%, belong to 10 genus ) and karyotypes of 16 species (80%, 9 genus ) ( Table ) . The idiograms of the karyotypes are shown in Fig. Afterreview-ing the recent cytological contributions, the writer supported separating Sciadopitys ( 2n=20, x=10) into Sciadopityaceae from Taxodiaceae ( 2n=22, x=ll). According to the relationships of other nine genera, the author suggests that they would be devided into five subfamilies: Ⅰ. Cryptomerioideae (Cryptomeria); Ⅱ. Taxodioideae (Glyp-tostrobus, Taxodium); Ⅲ. Sequoideae(Metasequoia,Sequoiadendron,Sequoia Ⅳ. ;Cunning-hamioideae (Cunninghamia, probably Athrotaxis yet); Ⅴ. Taiwanioideae (Taiwania). The evolutionary levels of the subfamilies and genera may rise gradually in the order. They are located on Evolutionary line A (Subfamily Ⅰ, Ⅱ, Ⅴ ) and L (Subfamily Ⅲ, Ⅳ ). The results have not been involvde in previous systems. So the chromosome data have played an important role in study on the systematic evolution of Taxodiaceae.