This award will support Professor David Mulcahy of the University of Massachusetts in a research collaboration with Professor Mauro Cresti of the University of Siena, Italy. The investigators intend to study microbial-like competition among pollen grains. Preliminary data indicate that while microspores (pollen grains-to-be) are still united in tetrads, they are competing with each other for resources. The major evidence for such intratetrad competition is that the deletion of one to three members within the tetrad is characterized by increases in the size of the viable members. The extent to which surviving members are able to absorb the resources of aborted members, the degree to which viable members compete among themselves, and the extent to which ultrastructural changes may express this competition are some of the topics that will be addressed by this research. In the angiosperms (and gymnosperms) pollen represents a microbial-like system of extremely large population and genotypes. Although pollen comprises a small portion of the angiosperm life cycle, it expresses, and thus exposes to selection, approximately 60% of all spirophytically expressed genes. This system is particularly effective in the angiosperms and may represent a significant contributor to the adaptive superiority of that group in the world flora. By combining the genetic approach of the U.S. researcher with the focus on pollen microstructure of the Italian investigator, this study will not only examine a newly appreciated aspect of microspore competition, it may also reveal information which could be useful in using pollen selection to develop plants resistant to agronomically and ecologically important stresses.
