Seed dispersion dynamics and population genetics of mangroves in Okinawa

红树林分布在热带的潮间带。种子和繁殖体主要通过潮汐传播，这种传播方式不同于陆生植物。研究了分布在日本冲绳琉球群岛的几种红树的种群遗传动态。应用微卫星或简单序列重复（SSRs）作为DNA标记，分析了水杨树（Avicennia marina）、布吉尼亚（burugiera gymnorrhiza）和茎尖根（Rhizophora stylosa）的遗传变异。为了优化这3种树木的DNA分离条件，对cetyl -trimethyl-铵溴酸铵（CTAB）法和Ice-cold buffer法进行了试验，改进的CTAB法和neasy Plant Mini Kit （Quiagen）的DNA产率均为可靠的。设计了24条丝状根霉微卫星引物，其中8条引物使用，但遗传变异较小。采用设计的7条引物对琉球群岛7个居群进行遗传变异分析。冲绳7个种群的杂合度在0.000 ~ 0.078之间。结果表明，7个种群的异花授粉率低于阿联酋和马尔代夫的4个种群。

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.