He Tianhua, Krauss Siegfried L, Lamont Byron B, Miller Ben P, Enright Neal J
Department of Environmental Biology, Curtin University of Technology, Perth, Australia.
Mol Ecol. 2004 May;13(5):1099-109. doi: 10.1111/j.1365-294X.2004.02120.x.
There is currently a poor understanding of the nature and extent of long-distance seed dispersal, largely due to the inherent difficulty of detection. New statistical approaches and molecular markers offer the potential to accurately address this issue. A log-likelihood population allocation test (AFLPOP) was applied to a plant metapopulation to characterize interpopulation seed dispersal. Banksia hookeriana is a fire-killed shrub, restricted to sandy dune crests in fire-prone shrublands of the Eneabba sandplain, southwest Australia. Population genetic variation was assessed for 221 individuals sampled from 21 adjacent dune-crest populations of B. hookeriana using amplified fragment length polymorphism. Genetic diversity was high, with 175 of 183 (96%) amplified fragment length polymorphism markers polymorphic. Of the total genetic diversity, 8% was partitioned among populations by amova and FST. There was no relationship between genetic diversity within populations and population demographic parameters such as population size and sample size. A population allocation test on these data unambiguously assigned 177 of 221 (80.1%) individuals to a single population. Of these, 171 (77.4% of total) were assigned to the population from which they were sampled and 6 (2.7% of total) were assigned to a known population other than the one from which they were sampled. A further 9 (4.1% of total) were assigned to outside the sampled metapopulation area, and 35 individuals (15.8%) could not be assigned unambiguously to any particular population. These results suggest that both the extent [15 of 221 (6.8%) individuals originating from a population other than the one in which they occur] and distance (1.6 to > 2.5 km), of seed dispersal between dune-crest populations is greater than expected from previous studies. The extent of long-distance interpopulation seed dispersal observed provides a basis for explaining the survival of populations of the fire-killed B. hookeriana in a landscape experiencing frequent fire, where local extinctions and recolonizations may be a regular occurrence.
目前，人们对远距离种子传播的性质和程度了解甚少，这主要是由于检测存在固有的困难。新的统计方法和分子标记为准确解决这一问题提供了可能。一种对数似然种群分配检验（AFLPOP）被应用于一个植物集合种群，以描述种群间的种子传播情况。胡克氏班克木是一种因火灾致死的灌木，仅生长在澳大利亚西南部埃纳巴沙原易发生火灾的灌木丛中的沙丘顶部。利用扩增片段长度多态性技术，对从21个相邻的胡克氏班克木沙丘顶部种群中采集的221个个体进行了种群遗传变异评估。遗传多样性较高，183个扩增片段长度多态性标记中有175个（96%）具有多态性。在总的遗传多样性中，8%通过分子方差分析（amova）和FST在种群间进行分配。种群内的遗传多样性与种群大小和样本大小等种群统计学参数之间没有关系。对这些数据进行的种群分配检验明确地将221个个体中的177个（80.1%）分配到了一个单一的种群。其中，171个（占总数的77.4%）被分配到了它们所采样的种群，6个（占总数的2.7%）被分配到了除所采样种群之外的一个已知种群。另外9个（占总数的4.1%）被分配到了采样集合种群区域之外，35个个体（15.8%）无法明确地分配到任何特定种群。这些结果表明，沙丘顶部种群之间种子传播的范围[221个个体中有15个（6.8%）来自与其所在种群不同的种群]和距离（1.6至>2.5公里）都大于先前研究的预期。观察到的远距离种群间种子传播范围为解释在频繁发生火灾的景观中因火灾致死的胡克氏班克木种群的存活情况提供了依据，在这种景观中，局部灭绝和重新定殖可能经常发生。
