遗传相似性特征及分布的研究对保护生物多样性、维护森林生态服务功能有积极的意义。选择广东湛江高桥红海榄Rhizophora stylosa纯林的400 m²固定样地，采用简单重复序列间区扩增ISSR和相关序列扩增多态性SRAP两种分子标记技术开展研究。用筛选出的10个ISSR引物和14个SRAP引物组合进行PCR扩增，分别共扩增出73个和111个清晰可读的位点，多态性位点数分别是60和88，多态性位点百分率分别是82.2%和79.3%。样方红海榄遗传相似系数变异范围为0.327～0.741，平均值为0.563，差值为0.414。在相似系数0.55的水平下，分为3个类群，遗传相似度为第一类群>第二类群>第三类群，遗传相似变动度第三类群>第二类群>第一种类群。在相似系数0.60的水平上，可分为8个类群。相似系数0.55的水平下红海榄聚集度越强，遗传相似度越高，遗传相似变动度越低。高桥红海榄群落样方分属于不同的类群，在遗传上有差异性，存在一定的基因交流；亲缘关系为远和较近的分布区间，遗传相似度和变动度中等，第三类群为优势种。初步证明红海榄聚集度与遗传相似度成正比，与遗传相似变动度成反比。

The study on genetic similarity characteristics and distribution has positive significance for biodiversity protection and maintain of forest ecological service function. A 400 m² fixedplot of Rhizophora stylosa was selected in Gaoqiao, Zhanjiang,Guangdong, and two molecular marker techniques of ISSR (Inter simple sequence repeat) and SRAP(Sequence-related amplified polymorphism) were used to study. Ten ISSR primers and 14 SRAP primers were selected and used for PCR amplification, and 73 and 111 discernible fragments were amplified, respectively.The polymorphic loci were 60 and 88, and the percentage of polymorphic loci were 82.2% and 79.3%. Genetic similarity coefficient ranged from 0.321 to 0.741, and genetic similarity average was 0.563, D-value was 0.414 in fxed plot of pure R. stylosa.At the level of 0.55 similarity coefficient, they were divided into three groups. The genetic similarity was Group 1 > Group 2 > Group 3, and the variation of genetic similarity was Group 1 > Group 2 >Group 3. At the level of 0.6 similarity coefcient, they were mainly divided into eight groups. At the level of 0.55 similarity coefcient,the degree of aggregation of R. stylosa was stronger, the genetic similarity was higher, and the variation degree of genetic similarity was lower. R. stylosa community quadrat in Gaoqiao belonged to different groups with genetic differences, and had a certain amount of gene exchange. The genetic relationship was between distant and near distribution section, and the genetic similarity and variation were moderate. The Group 3 was calculated to be the most dominant. It was preliminarily proved that the aggregation of R. stylosa was directly proportional to the genetic similarity, and inversely proportional to the genetic similarity variation.

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