金钱松（属）的细胞分类学研究

A CYTOTAXONOMICAL STUDY ON PSEUDOLARIX AMABILIS

我国特有植物金钱松Ｐｓｅｕｄｏｌａｒｉｘａｍａｂｉｌｌｓ的体细胞染色体数目为２ｎ＝４４，不同于ｎ＝１２（Ｍｉｙａｋｅ＆Ｙａｓｕｉ，１９１１）和２ｎ＝２４（Ｄｕｎｉｅｕ－Ｖａｂｒｅ，１９６１）的结果。核型公式为Ｋ（２ｎ）＝４４＝４ｓｍ＋４０ｔ）４ＳＣ）属３Ｂ类型，与Ｋ（ｎ）＝２２＝２ｍ＋２０ｔ（Ｓａｘ＆Ｓａｘ，１９３３）和Ｋ（２ｎ）＝４４＝４ｓｍ＋４０ｔ（Ｈｉｚｕｍｅ１９８８）有差异。染色体相对长度组成为＝４４＝４Ｌ＋１２Ｍ＿２＋２６Ｍ＿１＋２Ｓ。金钦松（属）不仅在染色体数目（２ｎ＝４４）和核型（具２０对端着丝粒染色体）而且它的一些形态、解剖学和植化性状与所有松科其它各属不同。另外，它的一系列形态、解剖、孢粉、生化、植化和古植物学特征显然表明把该属与落叶松属、雪松属一起组成落叶松亚科是不适宜的。因此似乎有理由把金钱松从该亚科分出并建立一个单型的金钱松新亚科。本文还对金钱松（属）核型可能由近缘的铁杉属起源和进化而来作了讨论。

The somatic chromosome number of PseudOlarix amabilis (Nekon)Rehd. Endemic to China is found to be 2n=44,which is different from n=12(Miyake & Yasu1,1911) and 2n=24(Dumeu-Vabre, 1961).The Karyotype formula is K(2n)=44=4sm+40t(4SC),which be-longs to 3B Type of Stebbins' Karyotypic symmetry and differs from n= 22= 2m+20t(Sax & Sax,1933)and 2n= 44=4sm+40t(Hizume, 1988). The chromosome complement of the species is2n=44=4L+12M_2+26M_1+2S according to the standard defined by Kuo et al.1972).The genus Pseulelarix differs from all the other pinaeeous genera not only in the chromosome number(2n=44)and the kacyotype(which 20 pairs of telocentric chromosomes),but also in eertain characters of morphology, anatomy and phytochemistry。 Besides,the evidence from mornhology,anatomy and palynology,biochemistry’phytochemistry and paleo bo tany shows obviously that it is not proper to group the genera, Larix and Cedrus with Pseudolarix into the same subfamily Laricoideae. So it seems reasonable to separate Pseudolarix from Laricoideae and to establish a new monotypic subfamily Pseudolaricoideae Li. The probable karyotypc origin and evolution of Pseudolarix from the related genusTsuga are discussed.