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观光木(Tsoongiodendron odorum)是我国特有的濒危植物,有居群较小、间断分布的特点。为探讨生境片断化对观光木居群的遗传多样性和交配系统的影响,我们采用8对微卫星引物对采自广东南昆山的观光木片断化居群的61个成株和15个家系共780个种子进行了基因分型,调查了5个空间隔离的斑块中观光木的两代遗传多样性以及各个层次(居群、斑块及个体)的交配系统参数。结果显示:片断化生境中观光木成株遗传多样性水平适中(HE=0.522),种子遗传多样性比成株稍低(HE=0.499),但没有显著的差异,近交系数在种子中也没有显著的升高,暗示生境片断化并没有侵蚀观光木的遗传多样性;多位点交配系统分析(MLTR)结果表明,该片断化生境中观光木为高度异交树种(tm=1.000),只有较少的双亲近交(biparental inbreeding)和相关性交配(correlated mating)事件发生,但有效花粉供体(effective pollen donor)数目较少(Nep为3.7-5.4);5个斑块间异交率差异不明显,但小的斑块有效花粉供体相对较多;另外,观光木个体之间的异交率存在明显差异,少数个体存在自交现象。这些结果为濒危物种观光木的长期保护提供了重要的遗传学信息。
Tsoongiodendron odorum is an endemic endangered plant in China, with a small population and intermittent distribution. In order to explore the impact of habitat fragmentation on the genetic diversity and mating system of Kogigetou population, we used 8 pairs of microsatellite primers to analyze the phenotypic changes of 61 adult and 15 pedigrees 780 seeds were genotyped and the genetic diversity of two generations of sightseeing timber in five spatially separated plaques and the mating system parameters at various levels (populations, patches and individuals) were investigated. The results showed that the genetic diversity of adult plants in fragmented habitats was moderate (HE = 0.522), and the genetic diversity of seedlings was slightly lower than that of adult plants (HE = 0.499), but there was no significant difference. The inbred coefficient There was no significant increase, suggesting that the habitat fragmentation did not erode the genetic diversity of Opuntia coativa. MLTL analysis showed that the species of Opuntia fortunei in the fragmented habitat was highly outcrossing species (tm = 1.000) Only a few biparental inbreeding and correlated mating events occurred, but the number of effective pollen donors was less (Nep 3.7-5.4). Out of the 5 plaques There was no significant difference in the rate of pollen donor but little pollen donor was found in the small plaques. In addition, there were significant differences in the rate of outgrowth among individuals. These results provide important genetic information for the long-term conservation of sightseeing timber for endangered species.