A Mass-Action Approach to the Study of Plant Mating Systems

尽管在过去的一个世纪里，对植物交配系统变异的理解取得了很大进展，但大多数研究都集中在近亲交配的负面影响所起的作用上。最近，开发了一种不同的方法，一种基于对植物繁殖和授粉生物学的一般分析的方法。它假设自交受精率至少部分取决于柱头上自交和异交花粉的相对数量--这一假设被称为质量作用假设。初步工作表明，即使不考虑近亲繁殖的影响，结合质量作用假设的模型也能够解释所观察到的植物交配系统的全部范围。这项前期工作将从两个方面扩展。首先，数学模型将被扩展以包括(1)更真实地表示植物种群的空间结构和(2)近亲繁殖衰退。其次，将利用千里光交配系统的多态进行模型预测的实验测试：(1)在自然种群和实验种群中直接估计模型的关键特征；(2)研究依赖频率的花粉输出在维持交配系统变异中的作用。

Although great progress in understanding the variation in plant mating systems has been made in the past century, most studies have focused on the role of the negative effects of inbreeding. Recently, a different approach has been developed, one that is based on a general analysis of plant reproduction and pollination biology. It assumes that rates of self-fertilization are determined, at least in part, by the relative amount of self and outcross pollen on stigmas--an assumption called the mass-action assumption. Preliminary work suggests that models incorporating the mass-action assumption may be able to explain the full range of observed plant mating systems, even without considering the effects of inbreeding. This preliminary work will be extended in two ways. First, the mathematical models will be extended to include (1) a more realistic representation of the spatial structure of plant populations and (2) inbreeding depression. Second, experimental tests of the model predictions will be made by taking advantage of a well studied mating system polymorphism in Senecio vulgaris (1) to make direct estimates of the key features of the model in natural and experimental populations and (2) to investigate the role of frequency-dependent pollen export in maintenance of the variations in mating system.