In flowering plants, the process of fertilization underlies production of seeds and fruits. Although structural events of double fertilization have been described, little is known about molecular mechanisms of fertilization. Plant sperm are embedded in pollen grains and move down growing pollen tubes. Near the egg, a pollen tube releases two sperm: one fuses with the egg to form the embryo, the other fuses with the central cell, adjacent to the egg, to form endosperm that supports growth of the developing embryo. A major unanswered question in plant reproduction is how sperm recognize eggs and central cells, adhere, and fuse. Recognition molecules may be located in or on gamete membranes. The goals of this project are to: (1) identify sperm membrane epitopes by screening antibodies to isolated plant sperm cells; (2) investigate sperm cell dimorphism by differential antibody binding; (3) determine the species specificity of sperm antigens; (4) determine whether sperm antigens change during sperm development; and (5) involve undergraduates in a pioneering research project. The results will further understanding of basic developmental mechanisms that function in plant reproduction. Antibodies will be raised to sperm of Brassica and will be tested on sperm of Gerbera and Lilium. The results will lead to a basic understanding of fertility and sterility: producing hybrids from incompatible species and preventing fertilization where male sterility is needed to prevent selfcrossing. The identity of sperm-specific membrane molecules will be valuable for future genetic engineering studies. Undergraduate students will gain valuable insight into active research. By solving problems and assisting in attainment of goals, they will gain research experience which will facilitate their development as scientists.
