入侵杂草假高粱的染色体变异及核型分析

CHROMOSOME VARIATION AND KARYOTYPE ANALYSIS OF INVASIVE WEEDSorghum halepenseL.

对入侵杂草假高粱(Sorghum halepenseL.)的根尖细胞进行染色体计数及核型分析,同时与二倍体高粱(SorghumL.)作比较。结果表明:供试材料假高粱的染色体数目为2n=34,染色体基数x=17,与原产地同物种(x=10)相比,发生了染色体数目变异,其核型公式为2n=2x=34=24m(2SAT)+10sm,为异源四倍体植物,核型类型为2B型,第15号染色体上有一对随体,最长与最短染色体长度比为2.30,臂比>2的染色体比例为18%,核型不对称系数为60.02%。与核型为2A型的高粱相比,二者的染色体数不成倍性关系,表明该假高粱种可能是由入侵种假高粱和禾本科其他植物通过远缘杂交形成的新变种。

Chromosome count and karyotype analysis of root tip cell in invasive weed Sorghum halepense L. was reported. At the same time, some characters, such as chromosome number, chromosome ploidy et al, between Sorghum halepense L. and Sorghum L. were compared. The results show that the chromosome number of Sorghum ha/epense L. is 2n = 34, the basic number of chromosome is x = 17, which arises chromosome number variation comparing with the same species（ x = 10） in origin. The karyotype formula of Sorghum halepense L.is 2n = 2x = 34 = 24m（2SAT） ＋ 10sm, which belongs to ＂2B＂ type, There are a pair of SAT in the No. 15 chromosomes. The chromosome length ratio is 2.30, Prop. of AR 〉 2 is 0.18, the index of asymmetry is 60.02 %. There is not precise mathematical relationship in chromosome number between Sorghum halepense L. and Sorghum L. These show that the variant Sorghum halepense L. may be a new species, which evolved through wide crosses between invasive species （2n = 4x = 40,n = 20）and other species in grass family （2n = 4x = 28, n = 14）.