澳大利亚三种Callitris植物的核型及其系统学意义

对澳大利亚特产的Ｃａｌｌｉｔｒｉｓ属植物Ｃ．ｐｒｅｉｓｓｉｉ，Ｃ．ｖｅｒｒｕｃｏｓａ，Ｃ．ｅｎｄｌｉｃｈｅｒｉ（柏科）的核型进行了分析，后２种的为首次报道。它们的核型公式分别为Ｋ（２ｎ）＝２２＝２２ｍ（２ＳＡＴ），２２ｍ（２ＳＡＴ）和２２ｍ（６ＳＡＴ），均属１Ａ核型类型。染色体相对长度组成同是２ｎ＝２２＝１０Ｍ＿２＋１２Ｍ＿１该３种及其他８种Ｃａｌｌｔｒｉｓ属植物一致的核型Ｋ（２ｎ）＝２２ｍ和１Ａ类型的通常被认为是最对称和原始的。因此该属在柏科的系统发育上也许处于相当原始的地位。

KARYOTYPE ANALYSIS OF 3 SPECIES OF CALLITRIS(CUPRESSACEAE)IN AUSTRALIA AND ITS PHYLOGEMETOC SOGMOFOCANCE

The present paper deals with karyotype analysis of Callitris ,C. verrucosa and C. endlicheri(Cupressaceae)endemic to Australia for the first time(except C.preissii).Their morphology of somatic chromosomes in seed root-tip cells,chromosome measurements and dia-grams are shown in Fig.1, Table 1 and Fig.2 respectively. The karyotypic fonnulas of the three species are K(2n)= 22= 22m(2SAT), 22m(2SAT) and 22m(6SAT)respectively.They all belong to IA Type ofStebbins'(1971) karyotypic asymmetry.The chromosome complements ofthem are all as the same as 2n=22=10M_2 12M_1 according to the standard defined by Kuo et al.(1972) based on relative length. The karyotype K(2n)= 22m and 1A Type of the 3 species and others of Callitris(Table2)are generally thought as symmetrical and primitive ones.The genus perhaps occupies a primitive phylogenetic position in Cupressaceae.