Bretschneidera sinensis, an endemic plant species native to China, is in peril of extinction because of scarce natural genetic resources and human destruction of its natural habitat. In order to assess the genetic integrity of the ex situ conservation populations of this species, the genetic diversity of four natural and two planted populations from Nanling Mountains was investigated using inter-simple sequence repeat (ISSR) markers. A total of 86 discernible DNA fragments were detected with 7 primers, and the 62 fragments were polymorphic. The percentage of polymorphic loci (PPB) and Shannon's phenotypic diversity index ( HPOP) in a population ranged from 36.05% to 53.49% , and from 0.204 0 to 0.307 9, respectively. The population genetic indexes of natural populations ( PPB =70.93% , HPOP =0.388 2) were higher than those of planted populations ( PPB = 53. 49% , HPOP=0. 294 1 ) . Analysis of molecular variance ( AMOVA) revealed that there was significant genetic difference among and within populations, and the genetic differences (ΦST = 0. 340 7) among natural populations were obviously higher than those of planted populations (ΦST =0. 224 8) . This result indicated high level genetic diversity at both population and species level of B. sinensis. The planted populations for ex situ conservation could not effectively protect the genetic diversity of this species from Nanling region. The planting material collection strategies for ex situ conservation should include as many as possible different populations.%为评价伯乐树迁地保护林的遗传完整性,采用ISSR分子标记技术对南岭山地伯乐树2个人工种群和4个天然种群的遗传多样性进行分析比较.结果显示:7条引物共检测出86个条带,其中62条为多态条带；各种群多态条带百分比(PPB)和Shannon表型多样性指数(HPOP)分别为36.05％ ～53.49％和0.204 0 ～0.307 9；天然种群PPB和HPOP分别为70.93％和0.388 2,高于人工种群(PPB=53.49％,HPOP=0.294 1).分子方差分析(AMOVA)表明,天然种群的遗传分化(φST=0.340 7)明显高于人工种群(φST=0.224 8).研究结果认为,伯乐树在物种水平和种群水平都具有较高的遗传多样性,已建立的迁地保护种群不能有效地保护南岭地区天然种群的遗传完整性,建议营建人工迁地保护种群尽可能地从多个不同种群中收集种质材料.
展开▼
