山茶科3种中国特有濒危植物的遗传多样性研究

猪血木(Euryodendron excelsum)、圆籽荷(Apterosperma oblata)和杜鹃红山茶(Camellia changii)均为我国特有的山茶科珍稀濒危植物。本研究应用随机扩增多态性DNA(RAPD)检测方法，比较了这3个物种的遗传多样性。利用20－24个随机引物从猪血木、圆籽荷和杜鹃红山茶居群中分别获得206－305条RAPD谱带，多态位点百分率(PPL)分别为51.80％、80.26％和38.83％；居群间遗传分化指数G_ST分别为0.3566、0.1713、0.1242。结果显示：自然分布较广的圆籽荷的遗传多样性高于另外两种自然分布区狭窄的种类。3个物种的遗传变异均主要存在于居群内，但猪血木居群间的遗传分化明显高于圆籽荷和杜鹃红山茶，这可能与其生境的严重片断化有关。根据3个物种不同的遗传结构特点，建议加强现有自然居群的就地 保护，促进居群自然更新；收集不同分布点的种源，尽快建立广东山茶科珍稀濒危植物的保育中心，深入开展人工快繁研究，扩大这些种群的数量。

Genetic diversity of three endemic and endangered species of the family Theaceae in Guangdong, China

Euryodendron excelsum , Apterosperma oblata , and Camellia changii are three species of the family Theaceae endemic to China. Genetic diversity of the three endangered species was studied using random amplified polymorphic DNA (RAPD). A total of 206-305 bands were generated by 20-24 random primers. Percentages of polymorphic loci( PPL ) of the three species were 51.80%, 80.26% and 38.83%, respectively, and coefficients of gene differentiation ( G ST ) were 0.3566, 0.1713, and 0.1242 , respectively. The results indicate that Apterosperma oblata , with wider natural distribution, has higher genetic diversity than the other two species with restricted natural distributions. Genetic variation mainly existed within populations; however, population genetic differentiation was obviously higher in Euryodendron excelsum than in the other two species, which possibly resulted from habitat fragmentation. Based on the different genetic structure, we put forward some conservation strategies, including in situ preservation, establishing a conservation centre for endangered species of the family Theaceae in Guangdong, and developing fast propagation techniques.