Data from: Resource allocation and seed size selection in perennial plants under pollen limitation

Pollen limitation may affect resource allocation patterns in plants, but its role in the selection of seed size is not known. Using an evolutionarily stable strategy model of resource allocation in perennial iteroparous plants, we show that under density-independent population growth, pollen limitation (i.e., a reduction in ovule fertilization rate) should increase the optimal seed size. At any level of pollen limitation (including none), the optimal seed size maximizes the ratio of juvenile survival rate to the resource investment needed to produce one seed (including both ovule production and seed provisioning); that is, the optimum maximizes the fitness effect per unit cost. Seed investment may affect allocation to postbreeding adult survival. In our model, pollen limitation increases individual seed size but decreases overall reproductive allocation, so that pollen limitation should also increase the optimal allocation to postbreeding adult survival. Under density-dependent population growth, the optimal seed size is inversely proportional to ovule fertilization rate. However, pollen limitation does not affect the optimal allocation to postbreeding adult survival and ovule production. These results highlight the importance of allocation trade-offs in the effect pollen limitation has on the ecology and evolution of seed size and postbreeding adult survival in perennial plants.

花粉限制（pollen limitation）可影响植物的资源分配格局，但其在种子大小选择中的作用尚不明晰。本研究借助多年生多次结实植物资源分配的进化稳定策略（evolutionarily stable strategy）模型，发现在密度无关种群增长（density-independent population growth）条件下，花粉限制（即胚珠受精率降低）应会提升最优种子大小。无论花粉限制程度如何（包括无花粉限制），最优种子大小均会使幼体存活率（juvenile survival rate）与生产单粒种子所需的资源投入（包含胚珠生产与种子养分供给（seed provisioning））之比达到最大化；换言之，最优解可使单位成本对应的适合度效应达到最大。种子资源投入可能会影响繁殖后成体存活率的分配。在本模型中，花粉限制会增大单粒种子的大小，但会降低整体繁殖资源分配，因此花粉限制也应会提升繁殖后成体存活率的最优分配比例。在密度依赖种群增长（density-dependent population growth）条件下，最优种子大小与胚珠受精率呈负相关。但花粉限制并不会对繁殖后成体存活率与胚珠生产的最优分配产生影响。上述研究结果凸显了分配权衡在花粉限制对多年生植物种子大小及繁殖后成体存活率的生态学与进化过程的影响中的重要性。