夏蜡梅核型的研究

本文首次报道我国特有重点保护植物夏蜡梅的核型为K(2n)=2x=22=18m+2m(SAT)+2sm,属Stebbins的“1A”类型,在演化上处于相当原始的地位。它的核型似比北美的光叶红对称和原始,因此至少夏蜡梅属可能起源于中国。

KARYOTYPE ANALYSIS OF CALYCANTHUS CHINENSIS (CALYCANTHACEAE)

Calycanthus chinensis Cheng et S.Y.Chang (Calycanthaceae) is a deciduous shrub endemic to Chekiang Province of China, which is protected specially by the country. The chromosome count and the karyotype are reported here for the first time. The somatic chromosome in root-tip cell of the plant is found to be 2n=22. Among these the tenth pair had submedian centromere, while other had median constrictions aad the fourth pair was SAT-chromosome. Measurements in microns of the chromosomes are given in Table 1. The photomicrograghs of the chromosome complement and the idio-gram of the karyotype are given in Fig. 1 and Fig. 2 respectively. The chromosome complement based on relative length is 2n = 22 = 6M2 2M2(SAT) 14M1 in the light of the method used by Kuo et al. According to the terminology defined by Levan et al., the karyotype formula is K(2n) = 22= 18m 2m(SAT) 2sm. The karyotype belongs to "2A" of Stebbins karyotypic symmetry and is generally regarded as a more primitive one.