Signalling pathways in pollen tube growth and reorientation

Plant fertilization is an essential process for seed production. One of the most interesting and important aspects is pollen tube growth from the stigma to the ovary. Understanding of the guidance mechanisms involved has been much debated, and important insights into the biochemical and physiological aspects of these events have been reported recently. Yet, the specific morphogenetic mechanisms which provide the pollen tube with these attributes remain very much unknown. In experimental terms, a substantial amount of research has dealt with the identification of cellular messengers, their capacity to generate a signal and how the information is coded in that signal. The role of cytosolic free calcium ([Ca2+](c)) has received a great deal of attention but research is extending rapidly to other areas. (C) 2000 Annals of Botany Company.