REU: The Genetic and Ecological Bases of Dioecy in Schiedea

不像大多数动物， 雄性和雌性，植物在繁殖中表现出很大的范围 系统. 大多数植物是雌雄同体的， 女性在同一朵花中发挥作用。 但许多其他物种， 包括一些重要的农作物，都有单独的雄性 和雌花在同一株植物上，或由 分离的雄性和雌性植物（diophyll）。 许多假设 被提出来解释育种系统的多样性， 植物和植物的进化。 一个主要的论点认为， dioectin已经进化到避免近亲繁殖的萧条。 近亲繁殖衰退发生在近亲个体 交配（或在极端情况下，自花授粉发生在 雌雄同体）和由此产生的后代表现出降低的活力 和繁殖能力。 在这项研究中，近交衰退在 夏威夷植物Schiedea属中的异黄酮的进化 （Carbellaceae）将进行检查。 这个团体显然是 进化中的杂交种，并展示了一系列的育种系统， 近缘物种。 这项研究具有特殊的紧迫性 因为许多重要的中间物种 脆弱的夏威夷生态系统濒临灭绝， 栖息地的破坏，引进的食草动物的放牧， 与引进的植物竞争。 近亲繁殖抑郁症是 也众所周知影响许多经济上重要的产量 农作物，如玉米（玉米）。 因素知识 导致dioxetamine可能会导致更大的能力，操纵性 在植物中的比例，并具有巨大的价值， 在生产水果或种子的女性，如在 许多作物品种的情况。

Unlike most animals which have individuals with separate male and female sexes, plants exhibit a great range in breeding systems. Most plant species are hermaphroditic with male and female function in the same flower. But many other species, including a number of important crop plants, have separate male and female flowers on the same plant or consist of populations of separate male and female plants (dioecy). Many hypotheses have been proposed to explain the diversity of breeding systems in plants and the evolution of dioecy. One major argument suggests that dioecy has evolved to avoid inbreeding depression. Inbreeding depression occurs when closely-related individuals mate (or in the extreme case, self-pollination occurs in hermaphrodites) and the resulting offspring show reduced vigor and ability to reproduce. In this research role of inbreeding depression in the evolution of dioecy in the Hawaiian plant genus Schiedea (Caryophyllaceae) will be examined. This group is apparently evolving dioecy and exhibits a range of breeding systems in very closely related species. This research is of special urgency because many of the important intermediate species from the fragile Hawaiian ecosystems are near extinction because of habitat destruction, grazing by introduced herbivores, and competition with introduced plants. Inbreeding depression is also well known to influence yield in many economically important crop plants, such as corn (Zea mays). Knowledge of factors causing dioecy may lead to greater ability to manipulate sex ratios in plants and is of tremendous value where yield depends upon the production of fruit or seed by the females as in the case of many crop species.