EAGER: Mechanisms of selection in plants with different reproductive strategies

Syracuse University, Syracuse NY

Investigators

Abstract

Reproduction is the most fundamental measure of evolutionary fitness for any living organism. A major aspect of the evolution of different reproductive strategies involves sexual selection - i.e.,competition among males to fertilize an egg, or the selective choice by females to mate with particular males. However it is still unclear the extent to which sexual selection occurs in plants, both because they often have male and female parts in the same flower, and because they are sessile and rely on pollinators to transfer the pollen (i.e., male gametes). Understanding the degree to which female plants exert choice for particular males could shed light on a central feature of plant fertilization and reproduction. This research will use a new assay to overcome the technical challenges of observing events taking place inside the reproductive tract of female plants. This research has the potential to pave the way for understanding the interactions between male and female gametes with implications for overcoming reproductive failure and increasing seed production, and for understanding fundamental processes in evolution that have thus far been difficult to study in plants. This research will elucidate the mechanisms of sexual selection in plants, focusing on female interactions with the growing pollen tube. The project will use a new combination in vivo/vitro assay where intact styles are pollinated and pollen tubes germinate and grow down the style. The pollinated style is excised and placed on artificial media with individually excised ovules. By varying the combinations and numbers of pollen grains and ovules, this approach provides the unique benefit of disentangling pollen tube-style interactions, pollen tube competition, and pollen tube-ovule interactions. In addition the research will use a phylogenetic comparative context to understand the strength and evolution of sexual selection, by exploiting diversity in pollination and mating system in the genus Thalictrum. The project will also benefit the scientific community and the public by including outreach and training components. Collaboration with the popular Museum of Science and Technology will provide mentoring and public workshops to Syracuse City school children.