Dissertation Research: Outcrossing Effects on Seed Development

植物产生更多的胚珠，而不是发育成种子。一些胚珠可能不会发育成种子，因为花粉管不能到达子房并使胚珠受精；另一些胚珠受精后败育。胚珠发育成种子的失败也可能取决于花粉供体的基因。一般来说，当两种类型的种子在同一果实中竞争时，由外源花粉产生的种子比由自花花粉产生的种子更有可能发育出来。试图确定异交种子优先发育机制的研究很少，尽管许多作者假设花粉管生长的变异是重要的。某些捐赠者的花粉管可能根本不会到达子房并使任何胚珠受精。如果用自体花粉繁殖的种子比用外来花粉繁殖的种子败育的频率更高，那么选择性败育也可能导致优先发育的模式。尽管种子败育可能在决定优先发育模式方面发挥作用，但尚未在任何植物中研究过由特定花粉供体产生的种子败育。这项拟议的工作与之前的研究不同，因为它将同时关注花粉管生长和种子败育的变化。PI已经开发出一种技术，使他们能够在胚珠开始败育时确定它们的基因组成。初步数据表明，由自交花粉产生的种子比由外来花粉产生的种子败育的频率更高。

Plants produce many more ovules than develop into seeds. Some ovules may not develop into seeds because pollen tubes fail to reach the ovary and fertilize ovules; other ovules are fertilized and then aborted. The failure of an ovule to develop into a seed can also depend on the genotype of the pollen donor. In general, seeds sired by foreign pollen are more likely to be developed over seeds sired by self pollen when both types of seeds are competing in the same fruit. There have been few investigations attempting to determine the mechanism of preferential development of outcrossed seeds although many authors have hypothesized that variation in pollen tube growth is important. Pollen tubes of certain donors may simply not get to the ovary and fertilize any ovules. Patterns of preferential development could also be caused by selective abortion if seeds sired by self pollen are aborted with greater frequency than seeds sired by foreign pollen. Despite the possible role of seed abortion in determining patterns of preferential development, abortion of seeds sired by specific pollen donors has not been examined in any plant. The proposed work differs from previous studies because it will look at both variation in pollen tube growth and seed abortion. The PIs have developed a technique that enables them to determine the genetic makeup of ovules as they begin to abort. Preliminary data suggest that seeds sired by self pollen are aborted with greater frequency than seeds sired by foreign pollen.