濒危植物猪血木人工繁殖幼苗的遗传多样性及对种群复壮的启示

Genetic diversity of artificially propagation seedlings of a critically endangered plant Euryodendron ex-celsum and its significance for population recovery

关键词:  濒危植物  猪血木  遗传多样性  AFLP  种群复壮

Key words:  endangered plant  Euryodendron excelsum  genetic diversity  AFLP  population recovery

摘要:

猪血木为山茶科特有的单型属珍稀濒危植物,目前仅在广东省阳春市八甲镇有分布,且种群数量不足200株,为给濒危植物猪血木的种群成功回归自然和种群复壮提供科学依据,采用AFLP分子技术,对7个种源人工繁殖的猪血木幼苗遗传多样性进行研究。结果表明:6对引物共检测到位点数为115个,其中多态位点数为68个,多态位点所占比率为59.13%,观察等位基因数(Na)为1.5826、有效等位基因数(Ne)为1.3813、Nei's基因多样性(H)为0.2215、Shannon多样性指数(I)为0.3280。UPGMA聚类将7个种源的幼苗划分为3支,不同种源间幼苗的遗传距离与种源地理距离存在显著相关性(P<0.05)。说明不同种源人工繁殖猪血木幼苗仍保持较高的遗传多样性。建议采集不同种源种子进行人工繁殖和人工种群构建,促进物种的种群复壮。

Abstract:

Euryodendron excelsum,which is endemic to China,is an endangered plant from the monotypic genus Euryodendron in the family Theaceae. The species is restricted to one remnant population with less than 200 individuals in Bajia region of Yangchun County,Guangdong Province. It is listed as a second class endangered plant for state protection in China. In the present study,genetic diversity of 7 provenances of E.excelsum artificially propagation seedlings was investigated by Amplified Fragment Length Polymorphism(AFLP). We recorded a total of 115 amplified bands using 6 pairs of AFLP primes,68 of which(PPB=59.13%)were polymorphic. The observed number of alleles(Na)and effective number of alleles(Ne)were 1.5826 and 1.3813,respectively. The average values of Nei's genetic diversity index(H)and Shannon polymorphism information index(I)were 0.2215 and 0.3280,respectively. E.excelsum artificially propagation seedlings from 7 provenances were clustered into three groups by UPGMA dendrogram,which was significantly correlated with the geographic distribution of the materials. The results of present study indicated that E.excelsum artificially propagation seedlings from 7 provenances had a relatively high level of genetic diversity. We suggest the future population recovery of this endangered plant could collect seeds and seedling propagation from the above 7 provenances to keep the genetic diversity. This study would provide a profound basis for the population recovery of E.excelsunm.