广西火桐自然种群和迁地保护种群的遗传多样性比较

摘要

采用 ISSR 标记方法，对广西火桐 Erythropsis kwangsiensis 10个自然种群和1个迁地保护种群的遗传多样性和遗传结构进行了分析和比较。结果表明：用10个引物从广西火桐总 DNA 中共扩增出60条带，其中多态性条带51条。自然种群中以维新种群的遗传多样性最高，而三叠岭瀑布种群最低。自然种群的总遗传变异 Ht 为0.2815，种群内遗传变异 HS 为0.0764，种群间遗传变异为0.2051，基因流为0.1832。迁地保护种群的 HEt 和HES 均为0.1188。自然种群间存在一定程度的遗传分化(Gst =0.7319)，种群间变异占主导地位。合并后的自然种群的多态性条带百分率（RPPB）、Nei’s 多样性指数(H)和 Shannon 信息指数(I)均高于迁地保护种群，分别为85.00%和31.67%、0.2841和0.1188、0.4285和0.1757。研究结果表明：广西火桐迁地保护种群的遗传多样性较低，未能涵盖整个种群。建议从多个自然种群中收集种子，尽可能多的采集样本，分区育苗种植，以增加遗传多样性水平。%Genetic diversity and structure of ten natural populations and one ex-situ conservation population of Erythropsis kwangsiensis were analyzed and compared by ISSR marker method. The results show that Sixty bands were amplified from total genomic DNA with 10 primers,in which there were 51 polymorphic bands; Of the ten natural populations, the percentages of polymorphic band (PPB), Nei’s diversity index (h) and Shannon information index (I) of Weixin population were the highest, and those of Sandieling waterfall were the lowest; The total genetic differentiation (Ht) of natural populations was 0.281 5, with HS=0.076 4 in populations, 0.205 1 among populations, and the gene flow was 0.183 2; However, the genetic differentiation values (HEt and HES) both were 0.118 8 in ex-situ conservation population; There existed a genetic differentiation (Gst= 0.731 9) among natural populations but the differentiation between populations occupied an leading position. The genetic diversity values of the natural population after merged, such as the percentage of polymorphic bands (RPPB), Nei’s diversity index (H) and Shannon information index (I) were all higher than that of ex-situ conservation population(REPPB), (HE), (IE) their were 85.00% (RPPB) and 31.67%(REPPB), 0.284 1 (H) and 0.118 8 (HE), 0.428 5 (I) and 0.175 7 (IE)m respectively. It was concluded that the ex-situ conservation population failed to cover the entire genetic diversity of E. kwangsiensis, so the suggestions are that seeds collecting should be selected from several wild populations, collected samples as many as possible and made seedling and planting with partition method, in order to increase genetic diversity of E. kwangsiensis.