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 results in triggering of the particular cellular and developmental responses of the organism. This review considers the cellular signals involved during different stages of gamete interactions in plants, including gamete attraction, recognition, fusion, zygotic activation and development. A wide range of signalling mechanisms can be seen to operate during fertilization, reflecting both the diversity of systems bringing gametes together and the different cellular responses to fertilization throughout the plant kingdom. Moreover, signals involved in triggering early development following gamete fusion appear to differ significantly even between species showing at least superficially similar cellular responses. Much of our current understanding comes from studies of 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.