子午岭中国沙棘亚居群的遗传多样性研究

A study on the genetic diversity of subpopulations of Hippophae rhamnoides ssp. sinensis at Ziwuling, Gansu

应用随机扩增多态性DNA(RAPD)方法对子午岭中国沙棘3个亚居群在小地理范围内的遗传变异进行了研究.结果表明,在居群水平上,子午岭中国沙棘居群存在比较丰富的遗传多样性,多态位点百分率为58.88％,Nei's基因多样性h=0.1744,Shannon's多态性信息指数I=0.2687.子午岭中国沙棘居群的遗传变异主要存在于亚居群内,亚居群间的遗传变异占总遗传变异的24.03％(Gst=0.2403),AMOVA的结果也表明,有18.80％的遗传变异存在于亚居群之间.这一结果符合中国沙棘风媒、异交的繁育系统特点,但亚居群间的基因分化系数仍要高于异交、风媒植物居群间遗传分化的平均值(Gst=0.1930).该地中国沙棘亚居群间较高的遗传分化与其生活环境和限制的基因流有关.

Randomly amplified polymorphic DNA (RAPD) marker variation was examined in three subpop-ulations of a natural population of H. rhamnoides L. ssp. sinensis Rousi collected from Ziwuling, Gansu. In total, 58.88% of the scorable markers were polymorphic at population level. Nei's gene diversity (h) and Shannon index (I) were 0.1744 and 0.2687, respectively, which showed a comparatively high genetic diversity. At the subpopulation level, the percentage of polymorphic bands (PPB) was 35.51%. The Gst showed 24.03% genetic variation among subpopulations, which indicated that most of the variation existed mainly within the subpopulations. The results of AMOVA, which showed 18.80% differentiation among the subpopulations, were consistent with the characteristics that H. rhamnoides L. ssp. sinensis Rousi is an outcrossing, wind-pollinated plant, but the genetic differentiation parameters of the subpopualtions were still a little higher than the mean value among populations of outcrossing, wind-pollinated plants (Gst=0.1930). The possible reasons for the comparatively high genetic differentiation among subpopulations of H. rhamnoides L. ssp. sinensis Rousi at Ziwuling were related to the environment and the limited gene flow.