何首乌种质资源核型分析及进化趋势研究

Analysis of Karyotype and Evolution Trend of Polygonum multiflorum Thunb. Germplasm Resources

以32份何首乌种质为研究材料,采用常规压片法,对其进行核型分析及进化趋势研究。结果表明:(1)32份何首乌种质存在二倍体(2n=2x=22)和三倍体(2n=3x=33)两种倍型;核型不对称系数As.K%和AI值分别在51.85%～61.52%和0.37～1.40;核型有"1A"、"1B"和"2A"3种类型,属于进化程度较低的植物。(2)在32份何首乌种质中,53.13%的种质为三倍体,表明多倍化在何首乌种质的进化中起着重要作用,但染色体结构变异也是其进化的主要途径之一。(3)何首乌各种质染色体形态变化较大,进化程度参差不齐,可能与种质的生境有一定相关性。(4)何首乌最初的起源中心可能在高纬度地区,在向低纬度地区迁移过程中发生了染色体数目及结构的变化。

Karyotypes and evolutionary trend of 32 Polygonum multiflorum germplasm resources were studied via squash method.The results showed that：（1）The ploidy levels were divided into diploid（2n=2x =22）and triploid（2n=3x=33）.Asymmetry index As.K%and AIvalue ranged from 51.85%to 61.52% and from 0.37to 1.40,respectively.The karyotypes of all the test materials consisted of＂m＂and＂sm＂ chromosomes,which include＂1A＂,＂1B＂and＂2A＂.The results indicated that the evolutionary degree of P.multiflorum was relatively low.（2）53.13% germplasms were triploid in 32 germplasm resources,which showed that polyploidization played an important role in the evolution of P.multiflorum.However,chromosome structural variation was one of the most important evolutionary ways.（3）Chromosomal morphological change of 32 germplasms resources was divergent and evolutionary degree was not consistent.The results showed that the existence of different ploidy levels is associated with the different habitats.（4）The primal centre of origin of P.multiflorum may be in the high latitudes,the chromosomal morphology and structures varied gradually when P.multiflorum migrated to low latitudes.