石蒜Lycoris radiata(L'Her.)Herb.及其矮小变种var.pumila Gery染色体核型的分析

据Inariyama^[5,6]与Bose和Flory^[4]报道,石蒜Lycoris radiata(L'Her.)Herb。染色体的数目为2n=33,都是R(棒)形染色体。如果把11作为石蒜属染色体的基数,那么具2n=33的石蒜显然是个三倍体,而且也是属内染色体的总数和R形染色体的数目最多者。

KARYOTYPE ANALYSES IN LYCORIS RADIATA(L'HER.)HERB.AND VAR.PUMILA GERY

Karyotypic analyses for Lycoris radiata (L' Her. ) Herb. andvar. pumila Gery, cultivated in Hangchow Botanical Carden, were carried out. The chromosomes in root-tip cell of these plants were found to be 33 and 22 respectively, both exhibited asymmetrical karyotypes with rod-shaped chromosomes. According to the chromosomal terminology defined by Levan et al. ^[9], the karyotype formula of L. radiata is therefore K (3n) =33=15t+18st, and of var. pumila, K(2n)=22=22t. These results agree well with those reported by Inariyama ^{[5, 6]} and Bose and Flory ^[4], but differ very much with that of Mooker-jea ^[10]. The chromosomes of the diploid L. radiata var. pumila, which has smaller bulbs and narrower and shorter leaves than the triploid L. radiata, though quite similar in relative lengths, differ remarkably in absolute lengths and arm ratios with the triploid. L. radiata is undoubtedly a near relative of I. rosea Traub et Moldenke. Since both belonging to the Subgenus Lycoris, they are very similar in karyotype and in external morphology as well. In the light of the fact that trivalent chro-mosomes were formed in heterotype metaphase in the pollen mother cells of L. radiata, Inariyama ^[5] held that the triploid was of autopolyploid origin. But the parental tetraploid plants have not yet been found. If taking 11 to be the basic chromosome number and Ro-bertsonian fusion the major tendency of karyotype evolution in Lycoris as stressed by Inariyama ^[7], Stebbins ^[11] and Jones ^[8] in particular, L. radiata var. pumila should be considered as one of the most primitive taxa which may be ancestral in the karyotype evolution of that gentus. Photomicrographs, karyotypes and idiograms of L. radiata and var. pumila are shown in Figs. 1, 2 and 3. Measurements in microns of the chromosome sets are given in Tables 1 and 2. The vouchers are preserved in the herharium of Hangchow Botanical Garden.