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，会有较大比例的受精花败育。虽然这种败育可能发生在果实发育的任何阶段，但大量败育往往发生在果实成熟期很晚的时候。许多理论都被用来解释这一现象，但人们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本，或者败育是否代表具有特定谱系的种子的死亡，例如，自花授粉后发育的果实。悬铃木为热带乔木，果实败育率较高。先进的DNA技术将被用来比较该物种的败育果实、未败育果实和已建立的幼苗，以证明自然选择是否作用于选择具有特定系谱或遗传组成的幼苗。这项研究将极大地促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活史的早期阶段所起的作用。这项研究的结果还可以预测热带森林碎片化对秀丽隐杆藻等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.