【摘要】 <正> 一、引言 据Inariyama与Bose和Flory报道,石蒜Lycoris ra-diata(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。Bo-更多还原

【Abstract】 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 theseplants were found to be 33 and 22 respectively, both exhibi-ted asymmetrical karyotypes with rod--shaped chromosomes.According to the chromosomal terminology defined by Levanet al. the karyotype formula of L. radiata is therefore K (3n) =33= 15t+18st, and of var. pumila, K(2n) = 22= 22t. Theseresults agree well with those reported by Inariyama[5,6] andBose and Flory, but differ very much with that of Mooker-jea. The chromosomes of thc diploid L. radiata var. pumila, whichhas smaller bulbs and narrower and shorter leaves than thetriploid L. radiata, though quite similar in relative lengths,differ remarkably in absolute lengths and arm ratios with thetriploid. L. radiata is undoubtedly a near relative of I. roseaTraub et Moldenke. Since both belonging to the SubgenusLycoris, they are very similar in karyotype and in externalmorphology as well. In the light of the fact that trivalent chro-mosomes were formed in heterotype metaphase in the pollenmother cells of L. radiata, Inariyama held that the triploidwas of autopolyploid origin. But the parental tetraploid plantshave not yet been found. If taking 11 to be the basic chromosome number and Ro-bertsonian fusion the major tendency of karyotype evolution inLycoris as stressed by Inariyamat, Stebbins and Jonesin particular, L. radiata var. pumila should be considered as oneof the most primitive taxa which may be ancestral in the ka-ryotype evolution of that gentus. Photomicrographs, karyotypes and idiograms of L. radiataand var. pumila are shown in Figs. 1, 2 and 3. Measurementsin microns of the chromosome sets are given in Tables 1 and2. The vouchers are preserved in the herharium of HangchowBotanical Garden.更多还原