The basic process of fertilization, fusion of egge sperm, is well known in animals. Flowering plants also produce eggs and sperm, but little is known about the mechanism of fertilization. Plant sperm are embedded in pollen grains and move down the growing pollen tube to the egg. Near the egg, the pollen tube bursts and releases two sperms. One sperm fuse with the egg to form the embryo of the seed. The second sperm fuses with the central cell adjacent to the egg to form a nutritive tissue for the developing embryo. A major unanswered question in plant reproduction is how sperm recognize the egg and central cell, and then adhere and fuse. A bioassay for sperm-egg adhesion will be developed using frozen sections of embryo sacs, including eggs and central cells, with isolated sperm. The bioassay will be useful to test mechanisms of sperm-egg recognition and to determine which antibodies to sperm cell surfaces can inhibit sperm-egg adhesion. The results will expand our knowledge of plant fertilization, create a model system for investigating plant reproduction, and lead to identification of key molecules in the fertilization process for future genetic transformations.
