杉科的染色体资料及在系统演化研究中的作用

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。

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

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.