8种蜡梅的染色体研究

.Study on Chromo-somes of 8 Species of Calycathaceae

以根尖和茎尖细胞对８种蜡梅进行了染色体组型分析，结果表明，全部种类的染色体基数都是１１，染色体绝对长度７．０２～３．２２μｍ。其核型公式有３种：美国蜡梅为２ｎ＝２２＝２２ｍ，西南蜡梅为２ｎ＝２２＝２０ｍ（２ｓａｔ）＋２ｓｍ，西美蜡梅、夏蜡梅、蜡梅、突托蜡梅、山蜡梅和柳叶蜡梅均为２ｎ＝２２＝２０ｍ＋２ｓｍ。比较组型的对称性，夏蜡梅属比蜡梅属更原始，而在两属中又以美国蜡梅和柳叶蜡梅分别为属内最原始的种。

Detailed karyotype studies had been carried out for eight speciesfrom calycanthaceae using the stem and root tips.The results showed thatthe basic number for all species was n=11.The absolute chromosome lengthranged from 7.02 to～3.22μm. Three karyotype formulas were found:2n=22=22m for Calycanthus floridus,2n=22=20m(2sat)+2sm for Chimonanthus campanulatusand 2n=22=20m+2sm for C.occidentalis,C.chinensis, Ch.praecox, Ch.nitens,Ch.grammatus and Ch.salicifolius.A comparison of karyotypic symmetry among species indicates that genus Calycanthus is more primitive than Chimo-nanthus in phylogeny,and C.floridus and Ch.salicifolius are the most prim-itive species within their genus.