COLLAB. RES.:Relative Fitness and Gender in Wild Populationsof Spergulaic marina (the sand-spurrey: Caryophyllaceae): AnExamination of the Assumptions of Theoretical Models

沙棘(Sperularia Marina)是世界上常见的一种天然滨海湿地生境。像大多数植物一样，海滨草的花通过产生花粉粒和胚珠来产生雄配子和雌配子。然而，与大多数物种不同的是，滨海海棠在花粉产生方面表现出十倍的变异，这代表着分配给雄性生殖。此外，在平均胚珠产量(每朵花50至150个胚珠)上，滨海海棠个体表现出三倍的变异，尽管这种变异范围在开花植物中并不少见。更重要的是，雄蕊数量和胚珠数量的变化都有遗传基础，因此很可能会随着时间的推移而变化。因此，这个物种提供了一个很好的机会来研究花资源分配给雄配子和雌配子的变异的原因和后果，通常被称为“性别分配”。目前，虽然已经有大量的理论工作对这一主题进行了研究，但还没有对这一理论假设进行深入探讨的实证研究。例如，长期以来，人们一直认为，增加雄性分配的选择(例如高花粉产量)必然会导致雌性分配的减少(例如，胚珠或行为的减少)，从而促进专门生殖系统的进化。然而，这一假设从未得到充分检验。我们对沙刺鱼生态遗传学的研究将通过测量雄蕊和胚珠生产的遗传成分，以及测量与增加分配给雄性或雌性生殖相关的任何“成本”，来检验性别分配理论的假设。此外，我们的数据将使我们能够评估S.marina及其类似物种的进化灵活性，以及它改变其生产性生物学以应对其日益受到威胁的栖息地变化的能力。

Sand-spurrey, Spergularia marina, is a common species of natural coastal wetland habitats throughout the world. Like most plant species, flowers of S. marina produce both male and female gametes through the production of pollen grains and ovules. However, in contrast to most species, S. marina exhibits ten-fold variation in pollen production, which represents allocation to male reproduction. In addition, S. marina individuals show three-fold variation in average ovule production (from 50 to 150 ovules per flower), although this range of variation is not uncommon in flowering plants. More importantly, the variation in both stamen number and ovule number has a genetic basic and is thus likely to show change over time in response to selection. This species, therefore, provides an excellent opportunity to investigate the causes and consequences of variation in the allocation of floral resources to male and female gametes, commonly known as "gender allocation". Currently, although there exists a great deal of theoretical work on this topic, there are no empirical studies that explore thoroughly the assumptions of this theory. For example, it has long been believed that selection to increase male allocation (e.g. high pollen production) should necessarily result in a reduction in female allocation (e.g., reduced ovule or deed production), promoting the evolution of specialized reproductive systems. This assumption, however, has never been adequately tested. Our study of the ecological genetics of sand-spurrey will test the assumptions of gender allocation theory by providing measurements of the genetic component to stamen and ovule production and measurements of any "costs" associated with increased allocation to male or female reproduction. Moreover, our data will allow an evaluation of the evolutionary flexibility of S. marina - and species similar to it - and its ability to alter its productive biology in response to changes in its increasingly threatened habitat.