BACKGROUND Declining resources due to climate change may endanger the persistence of populations by reducing fecundity and thus population fitness via effects on gamete production. The optimal mode of generative reproduction allocates the limited resources to ovule and pollen production in proportions that maximize the number of fertilized ovules in the population. In order to locate this optimum and derive reproduction modes that compensate for declined resources to maintain reproductive success, a model of gamete production, pollen dispersal, and ovule fertilization is developed. Specification of opportunities for compensation is given priority over specification of physiological or evolutionary mechanisms of adaptation. Thus model parameters summarize gametic production resources, resource investment per gamete, resource allocation as proportion of resources invested in ovules, and pollen density as size of the pollen dispersal range and proportion of pollen retained within the range. Retained pollen disperses randomly, and an ovule is fertilized if at least one pollen settles on its surface. The outcome is the expected number of fertilized ovules. RESULTS Maximization of fertilization success is found to require the investment of more gametic production resources in ovules than in pollen, irrespective of the parameter values. Resource decline can be compensated by adjusting the resource allocation if the maximum expected number of fertilized ovules after the decline is not less than the expected number the population experienced before the decline. Compensation is also possible under some conditions by increasing the pollen density, either by raising a low pollen retention or by shrinking the dispersal range. CONCLUSION Fertilization success in populations affected by resource decline may be maintainable by adjustment of the sexual allocation of gametic production resources or by increasing pollen density. The results have implications for insect pollination, sexual allocation bias, management measures, and metapopulation fragmentation.

中文翻译：

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生殖资源分配和花粉密度对植物受精成功的影响。

背景技术由于气候变化导致的资源减少可能会通过降低繁殖力来危及种群的持续存在，从而通过影响配子生产来危及种群的适应性。生殖繁殖的最佳模式将有限的资源分配给胚珠和花粉生产，使群体中受精胚珠的数量最大化。为了找到这种最佳状态并导出补偿资源下降以维持繁殖成功的繁殖模式，开发了配子产生、花粉传播和胚珠受精的模型。补偿机会的具体化优先于适应的生理或进化机制的具体化。因此，模型参数总结了配子生产资源、每个配子的资源投资、作为胚珠投资资源比例的资源分配、以及作为花粉传播范围大小和保留在该范围内的花粉比例的花粉密度。保留的花粉随机分散，如果至少有一个花粉落在胚珠表面，则胚珠受精。结果是受精胚珠的预期数量。结果发现，无论参数值如何，受精成功最大化需要在胚珠上投入比花粉更多的配子生产资源。如果资源下降后受精胚珠的最大预期数量不小于下降前种群经历的预期数量，则可以通过调整资源分配来补偿资源下降。在某些条件下，还可以通过增加花粉密度、提高花粉保留率或缩小传播范围来进行补偿。结论 受资源衰退影响的种群中的受精成功率可以通过调整配子生产资源的性别分配或增加花粉密度来维持。研究结果对昆虫授粉、性分配偏差、管理措施和集合种群破碎具有影响。