The Effect of Pollen Limitation on the Evolution of Mating System and Seed Size in Hermaphroditic Plants
The Effect of Pollen Limitation on the Evolution of Mating System and Seed Size in Hermaphroditic Plants
复制标题
花粉限制对雌雄同体植物交配系统和种子大小进化的影响
DOI：
10.1086/701782
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
M. Burd
中科院分区：
文献类型：
--
作者：
Qiaoqiao Huang;M. Burd
当花粉接收不足导致植物结出较少的种子和果实时，花粉限制会降低植物繁殖成功率并促进自体受精作为繁殖保证机制的进化。然而，花粉限制对交配系统和种子大小联合进化的影响尚不清楚。使用进化稳定的策略资源分配模型，我们表明，在适度的花粉限制和强烈的近交抑制选择完全异交的情况下，花粉限制也应该增加最佳种子大小。相反，花粉限制不应影响完全自交下的最佳种子大小，在这种情况下，胚珠受精是确定的。在中间条件下，如果胚珠受精的概率随着更多胚珠的产生而下降，则混合交配系统就会进化，因此具有近交抑制的自交种子为可能由于花粉限制而导致的较大异交种子提供了相同的边际适应性回报。在混合交配下，异交种子应大于自交种子，并且花粉限制不应影响异交或自交种子的最佳大小。我们的结果确定了花粉限制选择混合交配的新途径，并为为什么自交种子通常小于异交种子提供了适应性解释。
Pollen limitation, when inadequate pollen receipt results in a plant setting fewer seeds and fruits, can reduce plant reproductive success and promote the evolution of self-fertilization as a mechanism of reproductive assurance. However, the effect of pollen limitation on the joint evolution of mating system and seed size is not known. Using an evolutionarily stable strategy resource allocation model, we show that where moderate pollen limitation and strong inbreeding depression select for complete outcrossing, pollen limitation should also increase the optimal seed size. In contrast, pollen limitation should not affect the optimal seed size under complete selfing, in which case ovule fertilization is certain. Under intermediate conditions, a mixed mating system evolves if the probability of ovule fertilization declines as more ovules are produced, so that a selfed seed with inbreeding depression provides equal marginal fitness returns to a larger outcrossed seed that may result from pollen limitation. Under mixed mating, outcrossed seeds should be larger than selfed seeds, and pollen limitation should not affect the optimal size of either outcrossed or selfed seeds. Our results identify a novel pathway through which pollen limitation selects for mixed mating and provide an adaptive explanation as to why selfed seeds are often smaller than outcrossed seeds.