新疆阜康荒漠红砂种群遗传结构及其与生态因子的耦合关系(英文)

Genetic Structure of Reaumuria soongorica Population in Fukang Desert, Xinjiang and Its Relationship with Ecological Factors

应用RAPD标记技术对分布于新疆阜康荒漠的重要植物红砂(Reaumuria soongorica(Pall.)Maxim)种群遗传结构和遗传多样性进行了分析.15条随机引物对红砂7个亚种群的136个个体进行扩增,共检测71个位点,其中多态位点69个.研究结果表明:红砂种群的多态位点比率(PPB)为97.18%,显示出分布于过渡带的红砂种群内存在较高的遗传多样性.Shannon多样性指数(0.307 5)、Nei基因多样性指数(0.312 7)和基因分化系数(GST=0.312 0)揭示了红砂种群遗传变异多存在于亚种群内,而亚种群间的遗传分化则较小.红砂亚种群间的基因流Nm=1.102 8,Nm＞1但低于一般风媒传粉植物(Nm=5.24)的基因流水平,处于分化的临界状态.AMOVA分析说明红砂种群变异的61.58%存在于亚种群内,而亚种群间的变异占总变异的38.02%.另外,通过RAPD资料的聚类分析及相关性分析研究,发现红砂自然种群的遗传结构与绿洲荒漠过渡带的微生境生态因子(主要是土壤因子)相关,其中红砂亚种群遗传多样性水平与土壤中全磷和Cl含量呈显著负相关,与 C023含量呈显著正相关.而其它土壤生态因子则与红砂的遗传多样性指数的相关性均不显著(P＞0.05).表明红砂个体的分布可能与过渡带上壤的某些易溶性盐分相关.研究还发现,随着土壤中有机质、水分、全氮和全磷含量的减少,红砂种群的遗传多样性水平有上升的趋势.这可能与荒漠植物为了适应恶劣环境而在长期进化中产生更大的遗传变异潜力有关.本试验结果也进一步证实分布于较小范围内的红砂亚种群间的遗传距离、遗传多样性与亚种群的地理距离(经纬度差异)大小无显著的相关性.研究表明微生境的生态因子在红砂种群的适应性进化中起着重要的作用.

Genetic structure and differentiation of Reaumuria soongorica (Pall.) Maxim population from the desert of Fukang, Xinjiang, were assessed by means of random amplified polymorphic DNA (RAPD) markers. High genetic diversity and differentiation were revealed in the population of R soongorica by 15 random primers. One hundred and thirty-six individuals from seven subpopulations were sampled in the study. Seventy-one loci have been detected, and among them 69 were polymorphic. The mean proportion of polymorphic loci (PPB) was 97.18%. The analyses of Shannon information index (0.307 5), Nei's gene diversity (0.312 7) and G(ST)(0.312 0) indicated that there were more genetic variations within the subpopulations than those among the subpopulations. The results of AMOVA analysis showed that 61.58% of the genetic variations existed within subpopulations, and 38.02% among the subpopulations. The gene flow among the subpopulations of R soongorica (Nm = 1.102 8) was much less than that of the common anemophytes (Nm = 5.24), so genetic differentiation among the subpopulations occurred to some extent. Additionally, through the use of clustering and the correlation analyses, we found that the genetic structure of natural population of R soongorica was related to some ecological factors (soil factors mainly) of the oasis-desert transition zone. The genetic diversity level of R soongorica had negative correlation with the content of total soil P and Cl significantly (P < 0.05). On the contrary, it had significant positive correlation with CO32- (P < 0.05), showing that the distribution of the individuals of R soongorica in the sampled areas correlates with certain soluble salt. Furthermore, the genetic diversity of the natural population of R soongorica increased with the decreasing of the content of soil organic matters, water, total N and total P in soil. The paper concluded that the microenvironment ecological factors played an important role in the adaptive evolution of R soongorica population.