入侵植物剑叶金鸡菊种群遗传多样性及克隆多样性研究

Population Genetic Diversity and Clonal Diversity of Invasive Alien Plant Coreopsis lanceolata

克隆生长不可避免会增加同株异花授粉几率,从而影响有性适合度。探析精确尺度下种群遗传多样性和克隆多样性,有助于揭示克隆生长植物有性繁殖成功机制。剑叶金鸡菊(Coreopsis lanceolata)是菊科金鸡菊属多年生草本入侵克隆植物,文章采用AFLP分子标记方法,在精确尺度下比较分析了江西庐山高海拔公路旁绿化带、高海拔干扰小荒地和低海拔干扰小荒地3个剑叶金鸡菊种群的遗传多样性、克隆多样性和结实率,并探讨了克隆生长对其专性异交交配系统繁殖成功的影响。结果表明,(1)不同海拔、不同干扰生境的剑叶金鸡菊种群具有较高遗传多样性。种群多态性位点百分率(P)钧较高,最低为庐山植物园种群(LBG) 89.74%,最高石门涧种群(SMJ)可达95.13%。3个种群等位基因有效值(N_e)、Nei's多样性(H)和Shannon's信息指数(I)平均值分别为1.54、0.32和0.48。(2)剑叶金鸡菊种群的克隆多样性较高。3个种群基因型多样性(G/N)、Simpson多样性指数(D)和基因型均匀度(E)平均值分别为0.77、0.95和0.66。(3)种群结实率在64.97%—70.93%之间。研究结果表明有性繁殖能力强和多次引入是该克隆植物保持种群高遗传多样性的重要原因,遗传多样性高同时也提高了有性繁殖适合度,促进了有性繁殖成功。较高的种群克隆多样性降低了剑叶金鸡菊同株异花授粉几率,是其专性异交交配系统有性繁殖成功的重要策略。研究结果为揭示剑叶金鸡菊入侵生态学机制奠定了基础。

Clonal growth might affect the sexual fitness by enhancing the rate of geitonogamy.For obligated xenogamy clonal species,the knowledge in fine-scale of genetic and clonal diversity within the population is essential for understanding the mechanism of their reproductive success.Coreopsis lanceolata is an invasive clonal herbaceous perennial that belongs to the Asteraceae family.By using AFLP markers,our study aimed to assess the fine-scale genetic structure,clonal diversity and setting rate of C.lanceolata in different altitude and human disturbance populations growing at the side of high-speed road in Lu Mountain.And we also analyzed the potential influence of clonal growth of C.lanceolata on its sexual reproduction.The results showed that,(1)Percentage of polymorphic loci(P)were high in all different altitude and human disturbance populations,in which the highest(SMJ)and the lowest(LBG) were 95.13%and 89.74%,respectively.(2)Both the genetic diversity(Ne=1.54;I=0.48;H=0.32)and clonal diversity(G/N=0.77,D=0.95,E=0.66)in the three populations were proved in high level.And(3)a higher level of setting rate(64.97%–70.93%)were presented in the populations,suggesting that clonal reproduction reduce the success rate of sexual reproduction.Our study revealed that high genetic and clonal diversity are effective measures to decrease the geitonogamic pollination.We concluded that sexual reproductive ability and multiple introduction enhanced the genetic diversity in C.lanceolata.However,the high clonal diversity decreased the rate of geitonogamy,which improved the sexual fitness and facilitated the setting rate of C.Lanceolata.Our findings provide a theoretical basis for revealing the invasion mechanism of C.lanceolata.