Dissertation Research: Viability Selection at Three Early Life Stages of the Tropical Tree, Platypodium elegans

许多植物物种，尤其是树木，其受精花的比例相对较大。虽然这种败育可以发生在果实发育的任何阶段，但通常在果实成熟期很晚才发生大量败育。许多理论已经发展来解释这种现象，但对实际的堕胎过程知之甚少。特别是，通常不知道败育的果实是否代表受精胚珠的随机样品，或者败育是否代表具有特定谱系的种子的死亡率，例如，自花授粉后发育的果实。桔梗是一种晚果败育率较高的热带树种。 先进的DNA技术将用于比较该物种的败育果实、非败育果实和成熟幼苗，以记录自然选择是否在选择具有特定谱系或遗传组成的幼苗，这项研究将大大推进我们对植物育种系统的理解，并将更好地理解自然选择在植物生命周期早期阶段所起的作用。这项研究的结果也可以预测热带森林破碎化对像P.elegans这样的树木成功繁殖能力的影响。

9902041Hamrick & HuffordMany plant species, especially trees, abort relatively large proportions of their fertilized flowers. Although such abortion can occur at any stage of fruit development, often substantial abortion occurs very late in the fruit maturation period. Many theories have been developed to explain this phenomena, but very little is known about the actual abortion process. In particular, it is generally not known whether the fruits that are aborted represent a random sample of the fertilized ovules or whether abortion represents the mortality of seeds with specific pedigrees, e.g., fruits developing after self-pollination. Platypodium elegans is a tropical tree with relatively high late fruit abortion. Advanced DNA technologies will be used to compare aborted fruits, non-aborted fruits, and established seedlings of this species to document whether natural selection is acting to select seedlings with specific pedigrees or genetic compositions.This study will greatly advance our understanding of plant breeding systems and will provide greater understanding of the role natural selection plays in the early stages of plant life cycles. The results of this research may also allow predictions of the effect of tropical forest fragmentation on the ability of trees like P. elegans to successfully reproduce.