半夏属的染色体数目、倍性与珠芽发生的关系  

RELATIONSHIP BETWEEN OCCURRENCE OF BULBILS AND CHROMOSOME NUMBER AND PLOIDY IN PINELLIA (ARACEAE)

作　　者：李名旺[1] 顾德兴[1] 刘友良[1] 徐炳声[2] 

机构地区：[1]南京农业大学农学系,南京210095 [2]中国科学院植物所系统与进化植物学开放研究实验室北京,100093

出　　处：《植物分类学报》1997年第3期208-214,共7页Acta Phytotaxonomica Sinica

摘　　要：本文通过对半夏属Pinellia 5个种10个群体的染色体计数和珠芽数量统计,首次报道了5个染色体数目,同时发现珠芽的发生与染色体基数及多倍化程度有关:x=13的类群无珠芽,而x=9的有珠芽;在有珠芽的半夏P.ternata(Thunb.)Breit.中,平均每叶珠芽数随倍性的提高而增大。半夏是一个多倍体复合种,起源于无珠芽、染色体基数为x=7～9的二倍体祖先,可能是在该属的早期进化中由鹞落坪半夏P.yaoluopingensis X.H.Guo et X.L.Liu的x=13经非整倍性跌落而成,在发生上比鹞落坪半夏进化。By examining the somatic chromosome numbers and average numbers of bulbils per leaf of 10 populations belonging to 5 species of Pinellia, 5 chromosome numbers (P. peltata Pei2n=78, P.cordata N.E.Brown2n =72, P.ternata (Thunb.) Breit.2n=54, 99,108) new to this genus are reported. The present work also shows that the species with x = 13 including P. yaoluopingensis X. H. Guo et X. L. Liu (popullation Ⅰ~Ⅲ), P. tripar-tita (Blume) Schott (previous reports), P. pedatisecta Schott (population IV)and P. peltata (population V)have no bulbils at all,while those with x = 9 including P. cordata (population Ⅵ) and P. ternata (population Ⅶ~Ⅹ)have bulbils more or less depending on their ploidy——the average number of bulbils per leaf of hexaploid (population VII) is only 0.043, which is much lower than 1.95 of that of dodecaploids (population Ⅹ). Based on these observations , it could be supposed that polyploidy reinforce apomixis, the diploid ancestors of P. ternata have no bulbils and in Pinellia , x = 13 may be more primitive t = 9.The chromosome counts of the Araceae are changeable and complex, but appear to be explainable on the dual basis of ascending and descending dysploidy at secondary (paleopolyploid) level from a primitive basic number x=7. P. ternata is a polyploid complex and probably it came from a diploid ancestors without bulbils and with x = 7,8,9, etc. The basic chromosome numbers x =7,8,9 of Pinellia ternata may have been derived from x = 13 of P. yaoluopingensis by descending dysploidy in the early stage of the evolution of this genus. Then,as a result of secondary polyploidy, bulbils which enable the species to adapt to its varied environments occur and they might lead to a more rapid evolution in this species.

关 键 词：天南星科 半夏属 倍性 珠芽发生 染色体数目 

分 类 号：Q949.717.2[生物学—植物学]