Fernández-Manjarrés Juan F, Idol Jacquelyn, Sork Victoria L
Laboratoire d'Ecologie, Systématique et Evolution, Bât 360, Université Paris 11 Sud, 91405 Orsay Cedex, France.
J Hered. 2006 Sep-Oct;97(5):451-5. doi: 10.1093/jhered/esl022. Epub 2006 Sep 19.
Wind-pollinated forest trees usually have high outcrossing rates, but allogamy does not necessarily translate into high pollen movement. The goal of this study was to determine the outcrossing rates, pollen pool genetic structure, and the size of the effective pollination neighborhood in a population of black oak, Quercus velutina, in a Missouri oak-hickory forest. Based on 6 allozyme loci, 12 maternal trees, and 439 progenies sampled along a transect of 1300 m, we found complete outcrossing (t(m) = 1.000, P < 0.001) and small amounts of biparental inbreeding. Using a TwoGener analysis of the pollen gene pool, we found significant structure across maternal plants (Phi(FT) = 0.078, P < 0.001), which when corrected for adult inbreeding translates into Phi(FT) = 0.066 that corresponds to an effective number of pollen donors of 7.5 individuals. Assuming a bivariate normal distribution and an adult density of 16.25 trees ha(-1), we estimated that the effective pollination neighborhood area had a radius of 41.9 m. Even assuming that our estimates may be conservative, these findings join a growing body of evidence that suggest that the local neighborhood of wind-pollinated forest tree populations may be relatively small creating opportunities for local selection and genetic drift.
风媒传粉的森林树木通常具有较高的异交率，但异花授粉并不一定意味着花粉传播范围广。本研究的目的是确定密苏里州橡木-山核桃林中黑栎（Quercus velutina）种群的异交率、花粉库遗传结构以及有效授粉邻域的大小。基于沿着1300米样带采集的6个等位酶位点、12株母树和439个子代样本，我们发现完全异交（t(m)=1.000，P<0.001）以及少量的双亲近交。通过对花粉基因库进行双代分析，我们发现母本植株间存在显著的结构差异（Phi(FT)=0.078，P<0.001），校正成年个体近交后，Phi(FT)=0.066，相当于有效花粉供体数量为7.5个个体。假设为二元正态分布且成年植株密度为16.25株/公顷，我们估计有效授粉邻域面积的半径为41.9米。即使假设我们的估计可能较为保守，这些发现也加入了越来越多的证据，表明风媒传粉的森林树木种群的局部邻域可能相对较小，从而为局部选择和遗传漂变创造了机会。
