Laboratório de Ecologia Molecular Vegetal, Departamento de Botânica, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19031, CEP: 81531-990, Curitiba, PR, Brazil.
Laboratório de Interações e Biologia Reprodutiva, Departamento de Botânica, Setor de Ciências Biológicas, Centro Politécnico, Universidade Federal do Paraná, Caixa Postal 19031, CEP: 81531-990, Curitiba, PR, Brazil.
Am J Bot. 2018 Nov;105(11):1802-1812. doi: 10.1002/ajb2.1176. Epub 2018 Oct 22.
Seed and pollen dispersal are key processes shaping plant population dynamics and maintaining genetic diversity. The essence of these processes is the movement of propagules from a parental tree to the site of propagule establishment. The estimation of plant dispersal kernels has remained challenging due to the difficulty of making direct observations. We estimated the dispersal capacity of the endangered palm Euterpe edulis, whose seeds are dispersed by vertebrates and pollen by insects.
We used a hierarchical Bayesian model with genetic data from reproductive plants, juveniles, and embryos to estimate dispersal kernels. Our analyses account for genotyping error and uncertainty in parental assignment.
We found that seeds were dispersed at most a few hundred meters, but pollen was dispersed up to several kilometers. We hypothesize that this long-distance pollen dispersal is generated mainly by euglossine bees, whereas the main dispersal vectors for short-distance seed dispersal are thrushes. The long-distance dispersal of pollen suggests a high level of gene flow that should maintain genetic diversity of E. edulis. Despite the relation between long-distance dispersal and genetic diversity, we observed low genetic diversity and inbreeding within the local population, which are probably due to restricted gene flow due to the low density of this population and its aggregated spatial distribution.
We conclude that if conservation actions are able to restore the population density of E. edulis, the recovery of its genetic diversity will be facilitated because of its high dispersal capacity, especially with regard to pollen.
种子和花粉传播是塑造植物种群动态和维持遗传多样性的关键过程。这些过程的本质是从亲代树到繁殖体建立地点传播繁殖体。由于难以进行直接观察，植物扩散核的估计仍然具有挑战性。我们估计了濒危棕榈树 Euterpe edulis 的扩散能力，其种子由脊椎动物传播，花粉由昆虫传播。
我们使用了一种基于遗传数据的分层贝叶斯模型，这些数据来自生殖植物、幼树和胚胎，以估计扩散核。我们的分析考虑了基因分型错误和父母分配的不确定性。
我们发现种子的传播距离最多可达几百米，但花粉的传播距离可达数公里。我们假设这种远距离花粉传播主要是由 Euglossine 蜜蜂产生的，而短距离种子传播的主要传播媒介是画眉鸟。花粉的长距离传播表明基因流水平很高，这应该维持 E. edulis 的遗传多样性。尽管长距离传播与遗传多样性之间存在关系，但我们观察到当地种群的遗传多样性和近交程度较低，这可能是由于该种群密度低且空间分布聚集，导致基因流动受限。
我们的结论是，如果保护行动能够恢复 E. edulis 的种群密度，由于其高扩散能力，特别是花粉的高扩散能力，其遗传多样性的恢复将得到促进。
