荒漠十字花科植物粗果庭芥的核型分析

Karyotype Analysis of the Desert Cruciferous Plant Alyssum asycarpum Steph.ex Willd.

【目的】分析新疆荒漠十字花科植物粗果庭芥(Alyssum dasycarpum Steph.ex Willd.)的核型特征。【方法】以粗果庭芥根尖细胞为实验材料,采用常规压片法对细胞染色体数目、大小核型及倍性进行分析。【结果】该物种的染色体数目为2n=16,基数=8,二倍体;全部为中着丝粒染色体(m),染色体长度比为2.283,臂比>2的染色体比为0,核型公式为2n=2x=16=16 m,染色体组型属Stebbins核型分类中的"1B"类型,不对称系数为57.07%,低于60%,对称性高;核型分析过程中,未观察到随体存在。【结论】推测粗果庭芥在系统演化上可能属于较原始的种类。

[ Objective ] To analyze the karyotype characteristics of cruciferous plant Alyssum dasycarpum Steph. ex Willd. from the desert area in Xinjiang. [ Method]The somatic cells of root- tips from this species as experimental materials were used to observe the chromosome number, karyotype and ploidy characteristic by root -tip squashing method. [ Result] The chromosome number is 2n = 16; The basic chromosome number is confirmed to be x = 8; And this species is diploid; All of them are metacentric （m） chromosomes; The ratio of the longest chromosome to the shortest chromosome （Lc/Sc） is 2.283 ; The percentage of chromosomes with arm ratio （P. C. A） 〉2 is 0; the karyotype formula of this species is 2n = 2x = 16 -= 16m, which belongs to ＂1B＂ type of Stebbins karyotype classification; And the index of the karyotype asymmetry （As. K% ） is 57.07% and is lower than 60%, so the karyotype symmetry of this species is higher; The satellite on the chromosome of this species is never found in the process of the karyotype analysis. [ Conclusion] These results revealed karyotype of Alyssum dasycarpum is symmetrical to a higher degree, indicating that Alyssum dasycarpum belongs to a relatively primitive type and relatively old or the original plant in evolutionary processes.