The evolution of development of flowering plant reproductive cycles

它们生殖系统的极不稳定性是开花植物适应性和迅速多样化的核心。随着群体的起源，胚珠（未来的种子）被封闭在雌性组织中，需要一个新的花粉接收点（柱头）远离受精点（卵）。一个关键的创新，使这种柱头卵分离的起源是一个新的花粉管生长模式，精子可以携带到鸡蛋迅速和通过新的母体组织。该项目的主要目标是了解花粉管生长速率和生殖周期之间的关系。这些成果将有助于我们理解古代花粉-雌蕊相互作用和花生物学，这是大量研究最近进化的模型和作物系统的重点。该项目将涉及四种被子植物类群的早期和晚期花粉管发育的详细和全面的定量表征，这些类群跨越了现存被子植物之间最深的分歧，使用体内和体外田间和实验室实验。目的是确定潜在的发展变化的原因，在花粉管生长速率。这些精细的机制研究将伴随着大规模的比较分析，探讨花粉发育和重要的生态特征之间的关系，如繁殖速度，花的大小和寿命，以及营养代谢率。PI已经开发了一个协同教学计划，在植物发育和进化，将提供研究生一个集中的智力环境。包括对博士后研究人员和多名本科生的培训。该项目还包括国际合作，推广和教学。该项目的桥梁概念学科：PI作为两个NSF研究协调网络之间的联络，是田纳西州植物研究中心的创始董事会成员。外联活动包括公开讲座和新闻媒体采访。

The great lability of their reproductive systems is central to the adaptability and rapid diversification of the flowering plants. With the origin of the group, ovules (future seeds) became enclosed within female tissues, necessitating a new site of pollen reception (the stigma) far removed from the site of fertilization (the egg). A critical innovation enabling this stigma-egg dissociation was the origin of a new pollen tube growth pattern in which sperm could be carried to the egg rapidly and through novel maternal tissues. The primary goal of this project is to understand the relationship between the evolution of pollen tube growth rates and reproductive cycles. The outcomes will bear on our understanding of ancient pollen-pistil interactions and floral biology, the focus of a great number of studies on more recently-evolved model and crop systems.The project will involve detailed and comprehensive quantitative characterizations of early and late pollen tube development in four angiosperm taxa that span the deepest divergences among extant angiosperms using in vivo and in vitro field and lab experiments. The goal is to identify underlying developmental causes of variation in pollen tube growth rates. These fine-scale mechanistic studies will be accompanied by broad-scale comparative analyses probing the relationship between pollen development and important ecological traits, such as the speed of reproduction, floral sizes and longevity, and vegetative metabolic rates.The PI has developed a synergistic teaching program in plant development and evolution that will provide graduate students with a focused intellectual environment. Training for a postdoctoral researcher and multiple undergraduate students is included. The project also features international collaborations, outreach, and teaching. The project bridges conceptual disciplines: the PI serves as a liaison between two NSF Research Coordination Networks, and is a founding board member of the Tennessee Plant Research Center. Outreach activities include public lectures and news media interviews.