中国卵叶海桑遗传多样性的ISSR研究

卵叶海桑 (Sonneratiaovata)是海桑科濒危红树植物 ,在我国仅分布于海南文昌清澜自然保护区内。采用简单序列重复区间扩增 (ISSR)分子标记技术对该天然居群和东寨港红树林自然保护区引种的人工居群共 3个居群 3 9个个体进行了遗传变异分析。 1 1个引物共扩增出 1 85条带 ,其中 1 2 7条具多态性 ,多态位点百分率为 68.65 %。在居群水平上相对较低 ,多态位点百分率 3 6.76%～ 5 4.5 9% ,平均值为 47.2 1 %。Nei的基因多样性、Shannon信息指数在物种水平上分别为 0 .1 41 1和 0 .2 2 92 ;在居群水平上平均值分别为 0 .1 2 0 9和0 .1 91 0。Nei的遗传分化系数Gst表明 :87.5 8%遗传变异分布在居群内 ,1 2 .42 %的遗传变异分布在居群间。居群间的遗传一致度达 0 .970 7。东寨港迁地保护的人工居群有效地保护了卵叶海桑的遗传多样性。

Genetic diversity of Sonneratia ovata (Sonneratiaceae) in China detected by intersimple sequence repeats (ISSR) analysis

Sonneratia ovata is an endangered mangrove species of Sonneratiaceae restricted in Hainan Qinglan Natural Reserve of Wenchang City, Hainan Province. Inter-simple sequence repeats (ISSR) markers were used to investigate the genetic variations within and among the wild population and two introduced populations at Hainan Dongzhai Harbor Mangrove Natural Reserve. Leaf samples were collected from 39 individuals. Eleven ISSR primers gave rise to 185 discernible DNA bands of which 127 (68.65%) were polymorphic. However, there were relatively low levels of polymorphism at the population level with the percentage of polymorphic bands (P) from 36.76% to 54.59%, 47.21% on average. Nei’s genetic diversity (h) and Shannon’s information index(I) were 0.141 1 and 0.229 2 respectively at specific level, 0.120 9 and 0.191 0 at population level. Based on Nei’s Gst value, a large proportion of genetic variance (87.58%) was among individuals within population, 12.42% genetic variance was among populations. Genetic identity between populations was 0.970 7 on average. The ex situ conservation of S. ovata at Dongzhai Harbor Mangrove Natural Reserve was successful in the conservation of genetic diversity.