Cost-Benefits Tradeoffs Associated with Dimorphism in a Dioecious Plant

与雌雄异株植物二态性相关的成本效益权衡

• 批准号: 9629774
• 负责人: Lynda Delph
• 金额: $ 15万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-09-01 至 2000-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9629774&HistoricalAwards=false
• 关键词: Cost; Benefits; Tradeoffs; Associated; Dimorphism

9629774 Delph Some flowering plant species have separate male and female individuals and are termed dioecious. In addition to differing in their primary function (males produce pollen, whereas females produce seeds), males and females often exhibit sexual dimorphism in other traits (e.g., petal or leaf size, frequency of reproduction, and physiological traits). As a consequence of producing fruit, females of most dioecious species invest more biomass in reproduction than do males. This higher reproductive effort by females should mean that females will invest less in other structures than do males. Consequently, they should have a higher "cost of reproduction" than males; i.e., females often exhibit relatively slower rates of growth and/or higher rates of mortality. The investigators plan to study the dioecious plant, Silene latifolia, which does not appear to fit the pattern of females having a higher cost of reproduction. In this species, males grow less vegetatively and die at a younger age than females, even though females of this species do invest relatively more biomass in reproductive structures. In addition, in this species males produce 10 to 15 times more flowers than females, and male flowers are relatively small. The investigators will test the hypothesis that production of many, small flowers imposes a high cost of reproduction for the males, and that this cost can not be predicted simply by measuring biomass (i.e., carbon) invested in reproductive structures, because physiological differences between the sexes may also exist. The investigators will test this hypothesis in two ways: 1) by growing plants of known parentage in a common garden and greenhouse to observe whether variation in morphological and physiological traits is genetically based and correlated with flower number, and to observe relative longevity, and 2) by conducting an artificial selection experiment to reduce the magnitude of differences in flower size and number that exist between the sexes and obse rve whether certain physiological traits thought to be responsible for the cost of reproduction (such as respiration rate) also change with the change in the morphological traits. This will be the first test in plants of a phenomenon that has been reported for some animals: that sexual selection (selection for obtaining many mates) imposes a survival cost on males. Furthermore, the proposed research will contribute to our understanding of the evolution of sexual dimorphism in plants.

9629774 Delph有些开花植物物种有单独的雄性和雌性个体，被称为雌雄异株。 除了主要功能不同（雄性产生花粉，而雌性产生种子）外，雄性和雌性在其他性状上往往表现出性二态性（例如，花瓣或叶的大小、繁殖频率和生理性状）。 作为结果生产水果，大多数雌雄异株物种的女性投资更多的生物量在生殖比男性。 雌性更高的繁殖努力应该意味着雌性在其他结构上的投资比雄性少。 因此，她们的“生殖成本”应该高于男性;即，女性通常表现出相对较慢的生长速率和/或较高的死亡率。 研究人员计划研究雌雄异株的植物，宽叶蝇子草，它似乎不符合雌性繁殖成本较高的模式。 在这个物种中，雄性比雌性生长得更少，死亡年龄也更小，尽管这个物种的雌性确实在生殖结构中投入了相对更多的生物量。 此外，在这个物种中，雄性产生的花比雌性多10至15倍，雄花相对较小。 研究人员将测试这样一个假设，即生产许多小花会给雄性带来很高的繁殖成本，而这种成本不能简单地通过测量生物量来预测（即，碳）投资于生殖结构，因为两性之间的生理差异也可能存在。 研究人员将以两种方式检验这一假设：1）通过在普通花园和温室中种植已知亲本的植物来观察形态和生理性状的变化是否是基于遗传的并且与花数相关，并且观察相对寿命，和2）通过进行人工选择实验来减少两性之间存在的花的大小和数量的差异，观察某些被认为与繁殖成本有关的生理特征（如呼吸率）是否也随着形态特征的变化而变化。 这将是第一次在植物中测试一种现象，这种现象已经在一些动物中报道过：性选择（为获得许多配偶而进行的选择）对雄性施加了生存成本。 此外，拟议的研究将有助于我们了解植物性二型性的进化。