Baldoni A B, Wadt L H O, Campos T, Silva V S, Azevedo V C R, Mata L R, Botin A A, Mendes N O, Tardin F D, Tonini H, Hoogerheide E S S, Sebbenn A M
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Agrossilvipastoril, Sinop, MT, Brasil
Empresa Brasileira de Pesquisa Agropecuária, Embrapa Rondônia, , Brasil.
Genet Mol Res. 2017 Sep 21;16(3):gmr-16-03-gmr.16039756. doi: 10.4238/gmr16039756.
Due to the nutritional content and commercial value of its seeds, Bertholletia excelsa is one of the most important species exploited in the Amazon region. The species is hermaphroditic, insect pollinated, and its seeds are dispersed by barochory and animals. Because the fruit set is dependent on natural pollinator activity, gene flow plays a key role in fruit production. However, to date, there have been no studies on pollen and seed flow in natural populations of B. excelsa. Herein, we used microsatellite loci and parentage analysis to investigate the spatial genetic structure (SGS), realized pollen and seed dispersal, and effective pollen dispersal for two B. excelsa populations in the Brazilian Amazon forest. Two plots were established in natural forests from which adults, juveniles, and seeds were sampled. Realized and effective pollen flow was greater than realized seed flow. The distance of realized pollen dispersal ranged from 36 to 2060 m, and the distance of realized seed dispersal ranged from 30 to 1742 m. Both pollen and seeds showed a dispersal pattern of isolation by distance, indicating a high frequency of mating among near-neighbor trees and seed dispersal near to mother trees. Both populations present SGS up to 175 m, which can be explained by isolation by distance pollen and seed dispersal patterns. Our results suggested that fragmentation of these forest populations may result in a significant decrease in gene flow, due to the isolation by distance pollen and seed dispersal patterns.
由于其种子的营养成分和商业价值，巴西坚果是亚马逊地区被开发利用的最重要物种之一。该物种为雌雄同体，靠昆虫传粉，其种子通过重力传播和动物传播。由于坐果依赖于自然传粉者的活动，基因流在果实生产中起着关键作用。然而，迄今为止，尚未有关于巴西坚果自然种群中花粉和种子传播的研究。在此，我们使用微卫星位点和亲子关系分析，来研究巴西亚马逊森林中两个巴西坚果树种群的空间遗传结构（SGS）、实际花粉和种子传播以及有效花粉传播情况。在天然林中设立了两个样地，从中采集成年树、幼树和种子样本。实际和有效花粉传播大于实际种子传播。实际花粉传播距离在36至2060米之间，实际种子传播距离在30至1742米之间。花粉和种子均呈现出距离隔离的传播模式，表明近邻树木之间交配频繁，种子在母树附近传播。两个种群在175米范围内均呈现出空间遗传结构，这可以通过距离隔离的花粉和种子传播模式来解释。我们的结果表明，由于距离隔离的花粉和种子传播模式，这些森林种群的碎片化可能导致基因流显著减少。
