基于ISSR标记的南方红豆杉野生种群和迁地保护种群的遗传多样性和遗传结构分析

摘要

Genetic diversity and structure of three wild populations ( including populations of Huanggang and Huangsha of Jiangxi and Fengxi of Fujian), two cultivated and two derived populations of ex-situ conservation (all located in Nanjing Botanical Garden Mem.Sun Yat-Sen of Jiangsu and Lushan Botanical Garden of Jiangxi) of Taxus chinensis (Pilger) Rehd.var.mairei (Lemée et Lévl.) Cheng et L.K.Fu were analyzed and compared by ISSR marker method.The results show that 73 bands are amplified from total genomic DNA of T.chinensis var.mairei with eight primers, in which there are 62 polymorphic bands.Percentage of polymorphie band ( PPB), Nei' s diversity index (h) and Shannon information index (Ⅰ) of two ex-situ conservation derived populations are higher, and those of three wild populations are in the middle, but those of two ex-situ conservation cultivated populations are lower.Both of combined ex-situ conservation derived population and wild population have higher genetic diversity,and their PPB, h and Ⅰ are close with values of 78.08％ and 82.19％, 0.207 6 and 0.205 8, 0.322 9 and 0.325 9, respectively.But there are differences in genetic structure of two populations above, and genetic differentiation coefficient ( GST ) of ex-situ conservation derived population is 0.068 9, which is obviously lower than that of wild population (0.168 5).Genetic diversity of combined ex-situ conservation cultivated population is relatively lower, its PPB, h and l is 60.27％, 0.180 7 and 0.275 2,respectively, and its GST is the highest (0.251 4), which is obviously higher than those of combined wild population and ex-situ conservation derived population.It is concluded that under conditions of secondary forest environment in botanical garden, genetic diversity of ex-situ conservation derived population of T.chinensis var.mairei returning to natural habitat tends to be abundant and is close to that of wild population, thus, it is proved that botanical garden has the huge potential in ex-situ conservation of endangered plants, which was never known in the past.%采用ISSR标记方法,对南方红豆杉[Taxus chinensis(Pilger)Rehd.var.mairei(Lemée et LéV1.)Cheng et L.k.Fu]3个野生种群(包括江西黄港和黄沙种群以及福建枫溪种群)、2个迁地保护栽培种群及2个迁地保护衍生种群(均位于江苏南京中山植物园和江西庐山植物园)的遗传多样性和遗传结构进行了分析和比较.结果显示:用8个引物从南方红豆杉的基因组总DNA中共扩增出73条带,其中多态性条带62条.2个迁地保护衍生种群的多态性条带百分率(PPB)、Nei's多样性指数(h)和Shannon信息指数(I)较高,3个野生种群的PPB、h和I值总体上居中,而2个迁地保护栽培种群的PPB、h和I值较低.合并后的迁地保护衍生种群以及野生种群均有较高的遗传多样性,二者的PPB、h和I值相近,分别为78.08%和82.19%、0.207 6和0.205 8、0.322 9和0.325 9;但二者的遗传结构存在差异,迁地保护衍生种群的遗传分化系数(GST)为0.068 9,明显低于野生种群(0.168 5).合并后的迁地保护栽培种群的遗传多样性相对较低,PPB、h和I值分别为60.27%、0.180 7和0.275 2;而GST值最高(0.251 4),明显高于合并后的野生种群和迁地保护衍生种群.研究结果表明:在植物园次生林环境条件下,回归到自然生境下的南方红豆杉迁地保护衍生种群的遗传多样性趋于丰富并接近野生种群,从而证明了植物园在濒危植物迁地保护中具有以往未被认识到的巨大潜力.