文冠果花粉供体的多样性对果实产出的影响

Effect of Pollen Donor Diversity on Fecundity in Xanthoceras sorbifolium

很多植物的花,其柱头上接受的花粉供体多样性数量通常与果实成熟和种子产出有关。关于提高花粉多样性能否增加植物的生殖产出问题,文献中时常有相互矛盾的结论。本研究通过对自交不亲和性植物文冠果(Xanthoceras sorbifolium)进行1、2、3、4种花粉供体传粉实验,调查了不同花粉供体数量对文冠果雌性生殖的影响。结果表明,增加亲和花粉供体的多样性,一定程度上提高了花序上果实的坐果数量,同时也增加了果实中种子的数量及单粒种子重量。对文冠果授以4种亲和性花粉供体后,花序上成熟果实的平均数最多;3种亲和性花粉供体传粉后,每个果实中的种子数最多,单粒种子也最重。如果混合花粉中含有自交花粉,那么果实将败育。除花粉多样性影响雌性生殖产出外,母本基因型也具有重要影响,即增加文冠果种植品系的多样性,将有助于提高果实和种子产量。本研究还讨论了花粉遗传多样性效应、母本交配选择及果实选择性败育假说。

The number of stigma pollen genotypes is often related to fruit maturation and seed product in many angiosperms species. However, there is conflicting evidence that increasing pollen diversity can enhance plant fecundity, The present work examined whether genetic diversity of pollen （1, 2, 3 and 4 donors） affected plant fecundity in Xanthoceras sorbifolium, a self-incompatible species. Results showed that increasing the diversity of compatible pollen enhanced the mean number of fruit in an inflorescence and seed number per fruit and mean seed weight. The highest mean number of fruits in an inflorescence, the highest mean number of seeds per fruit, and the highest mean weight of seeds were produced by four, three and three compatible donors, respectively. If mixed pollen donors contained self-pollen, all fruits were aborted. In addition to diversity of pollen genotypes, recipient genotypes also affected female reproductive success. The present results suggest that greater attention to high diversity varieties may help maintain or enhance fruit and seed production in X. sorbifolium. The efffect of pollen genetic diversity, maternal mate choice and selective fruit abortion were discussed in this paper.