Seed dispersion dynamics and population genetics of mangroves in Okinawa

红树林分布在热带潮间带。种子和繁殖体主要是通过潮汐传播的，这种传播方式不同于陆生植物。为了研究分布于日本冲绳琉球群岛的几种红树植物的种群遗传学动态，利用微卫星或简单重复序列(SSR)作为DNA标记，对白骨壤、木犀草和花旗根的遗传变异进行了分析。为了优化这3个树种的DNA提取条件，对十六烷基三甲基溴化铵(CTAB)法、冰冷缓冲法等几种方法进行了试验，结果表明改进的CTAB法和DNasy植物迷你试剂盒(Quiagen)提取的DNA效果较好。利用设计的7对引物对琉球群岛7个居群的遗传变异进行了分析。冲绳7个群体的杂合度在0.000~0.078之间。结果表明，7个居群的异花授粉率低于阿联酋和马尔代夫的4个居群。

Mangroves are distributed at inter-tidal zone in tropics. Seeds and propagules are dispersed mostly by tides, and this seed dispersion manner is different from it of terrestrial plants. The purpose of the study is to investigate dynamics of population genetics of some mangrove tree species distributed in Ryukyu Islands, Okinawa, Japan.Microsatellites or simple sequence repeats (SSRs) were applied as DNA markers to Avicennia marina, Buruguiera gymnorrhiza and Rhizophora stylosa to analyze genetic variation. To optimize DNA isolation condition for these three tree species, several methods such as Cetyl-trimethyl-ammonium bromid (CTAB) method and Ice-cold buffer method were tested, and modified CTAB method and Dneasy Plant Mini Kit (Quiagen) showed the reliable DNA yield.Twenty-four microsatellite primers were designed for Rhizophora sylosa, and among them, 8 primers were used but genetic variation was small. For A. marina, 7 designed primers were applied to analyze genetic variation of 7 populations in Ryukyu Islands. Hetetozygosity (He) of 7 populations in Okinawa was between 0.000 and 0.078. It suggested that cross-pollination rates of 7 populations were smaller than that of 4 populations in the United Arab Emirates and Maldives.