Collaborative Research: The Evolutionary Consequences of Floral Display Size in a Self-Compatible Plant

在一株自交植物上同时开花的花的数量可能对繁殖的成功有深远的影响。例如，具有大显示屏的植物可能会受到更多传粉者的访问，从而增加种子产量。然而，大型显示器也可能带来巨大的成本。自花授粉更有可能，因为大型展示促进了植物内部传粉者的运动。如果存在近亲繁殖抑制，女性的繁殖成功率将受到影响。自花授粉也可能减少花粉传递给其他植物，降低雄性繁殖的成功率。本项目利用一种新颖的实验系统来验证这种假设，即这些相互冲突的选择压力有利于中等大小花的进化。猴花（Mimulus ringens）展示将在由遗传上不同的个体组成的复制（克隆）种群中进行操作。这些阵列有助于明确地衡量亲子关系和个人自恋率。在一个共同的遗传背景下，对花展示大小的操纵可以检验花展示和其他性状如何相互作用，影响生殖成功。为了研究自然种群的花卉展示是如何进化的，我们将在一个普通花园的野外条件下进行人工选择实验。这些实验将提供关于花展示的适应性意义的独特数据，并将增强我们对植物交配系统进化的理解。这项研究的结果也将对农业（作物育种以最大限度地提高产量）和保护生物学（最大限度地提高植物园中濒危物种的繁殖成功率）具有重要意义。

Mitchell9903308The number of flowers blooming simultaneously on a self-fertile plant may have profound consequences for reproductive success. For example, plants with large displays may receive more pollinator visits, increasing seed production. However, large displays may also entail significant costs. Self-pollination is more likely, since large displays promote within-plant pollinator movements. If there is inbreeding depression, female reproductive success will suffer. Self-pollination may also decrease pollen transfer to other plants, reducing male reproductive success. This project utilizes a novel experimental system to test the hypothesis that these conflicting selection pressures favor the evolution of intermediate-sized floral displays. Monkeyflower (Mimulus ringens) displays will be manipulated in replicate (cloned) populations consisting of genetically distinct individuals. These arrays facilitate unambiguous measures of paternity and individual selfing rates. Manipulation of floral display size on a common genetic background allows examination of how floral display and other traits interact in affecting reproductive success. To examine how floral display may evolve in natural populations, an artificial selection experiment will be conducted under field conditions in a common garden. These experiments will provide unique data concerning the adaptive significance of floral displays, and will enhance our understanding of the evolution of plant mating systems. The results of this research will also have important implications for agriculture (breeding of crops to maximize yield) and conservation biology (maximizing reproductive success of endangered species in botanic gardens).