TANSLEY REVIEW NO-70 - SIGNAL-TRANSDUCTION DURING FERTILIZATION IN ALGAE AND VASCULAR PLANTS

Fertilization involves interaction between two gametes and exchange of genetic information. In addition, information is transferred which re sults in triggering of the particular cellular and developmental respo nses of the organism. This review considers the cellular signals invol ved during different stages of gamete interactions in plants, includin g gamete attraction, recognition, fusion, zygotic activation and devel opment. A wide range of signalling mechanisms can be seen to operate d uring fertilization, reflecting both the diversity of systems bringing gametes together and the different cellular responses to fertilizatio n throughout the plant kingdom. Moreover, signals involved in triggeri ng early development following gamete fusion appear to differ signific antly even between species showing at least superficially similar cell ular responses. Much of our current understanding comes from studies o f a few easily accessible systems though recent developments in gamete isolation, in vitro fertilization and embryo culture should increase the scope for studies of signalling mechanisms in vascular plants.