Dissertation Research: Sex Allocation and Reproductive Success in a Perennial Hermaphrodite, Solanum carolinense

9411513 Meagher生态学理论预测，植物上花的大小或数量应该对该植物的繁殖成功有很大影响，特别是在花粉传播方面，因此花更多或更大的植物将增加其作为父本的繁殖成功。另一方面，植物的资源有限，不仅要用来吸引传粉者，还要用来充实果实(雌性生殖成功的一部分)、生长、储存和存活。这导致了工厂内部的基本冲突。这两个概念的综合--通过每个性别和分配水平的冲突而获得的生殖成功--在两性植物中受到了阻碍，因为与确定特定性别的适合度和将花冠(花瓣)大小等特定特征分配给雄性或雌性成功有关的问题。这项研究将结合分配和适合度成分的方法，以确定不同的花性状在生殖成功中的确切作用。这项拟议的研究将确定多年生植物龙葵性别功能的资源分配，并将分配模式与通过雄性和雌性功能实现的适合度相关联。已种植的实验种群中，个体果实和种子在两个生长季节(雌性适合度)和雄性亲子关系(通过遗传分析确定)将与花的大小和数量的个体差异有关。因此，这项研究将深入了解资源分配对两性植物中通过每种性别获得的适合度的影响，以及两性之间分配和适合度的相互关系。此外，还将在植物之间进行受控杂交，以确定花性状的遗传力，从而确定分配制度进化的潜力。如果花的大小是由环境心理决定的(例如，如果在营养浓度略高的地区生长的个体的花部分较大)，由于分配制度而造成的生殖能力的任何差异将不会遗传给后代，花的大小及其与繁殖成功的关系是随机影响。除了对植物繁殖成功的基本了解做出贡献外，该项目还将具有潜在的应用意义。该项目的研究物种卡罗琳茄子被评为1980年十种最严重的牧草之一，这是因为存在有毒的生物碱、皮刺和粗大的持久根，这些有助于个体植物的克隆扩散。因此，它是一个具有重要商业价值的物种。了解这种杂草的分配权衡可能有助于农民目前采取的控制措施。此外，所讨论的有关权衡的具体问题在食用植物育种工作中有直接的应用，因为这些结果将有助于解释水果生产中的品种差异作为花分配的变化的函数。

9411513 Meagher Ecological theories have predicted that the size or number of flowers on a plant should have a large effect upon the resulting reproductive success of that plant, particularly in terms of pollen spread, so that a plant with more or larger flowers will increase its reproductive success as a male parent. On the other hand, a plant has a limited resource pool which must be allocated not only to attracting pollinators, but also to filling fruit (a component of female reproductive success), growth, storage, and survival. This leads to a basic conflict within a plant. Synthesis of these two ideas--reproductive success gained through each gender and allocation-level-conflicts--has been hampered in hermaphroditic plants by problems associated with determining gender-specific fitness and assigning specific characters, such as corolla (petal) size, to either male or female success. This study will integrate allocation and fitness-component approaches to identify the precise role of different floral characters in reproductive success. The proposed research will determine resource allocation to gender functions in the perennial plant Solanum carolinense, and relate allocation patterns to realized fitness through both male and female functions. Experimental populations of S. carolinense have been planted, within which individual fruit and seed set over two growing seasons (female fitness) and male paternity (determined through genetic analysis) will be related to individual variation in the size and number of flowers. This study will therefore provide insight into the effect of resource allocation on the fitness gained through each gender in a hermaphroditic plant, and into the interrelationships of allocation and fitness between genders. In addition, controlled crosses will be performed between plants to determine the heritability of floral characters, so as to ascertain the potential for evolution of allocation regime. If flower size is environ mentally determined (for example, if larger flower parts are found on individuals growing in areas of slightly higher nutrient concentrations), any difference in reproductive ability due to allocation regime will not be passed on to offspring, and flower size and its relation to reproductive success is a random effect. In addition to contributions to basic understanding of plant reproductive success, this project will also have potential applied significance. The study species for this project, Solanum carolinense, was named one of the ten worst pasture weeds in 1980, due to the presence of toxic alkaloids, prickles, and thick persistent roots which aid in clonal spread of individual plants. It is therefore a commercially important species. Understanding allocation tradeoffs in this weed could contribute to control efforts currently practiced by farmers. In addition, the specific questions addressed concerning tradeoffs have direct applications to food plant breeding efforts, in that the results will help to explain cultivar variation in fruit production as a function of variation in floral allocation.