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 stig ma to the ovary. Understanding of the guidance mechanisms involved has been much debated, and important insights into the biochemical and physiologica l aspects of these events have been reported recently. Yet, the specific mo rphogenetic mechanisms which provide the pollen tube with these attributes remain very much unknown. In experimental terms, a substantial amount of re search has dealt with the identification of cellular messengers, their capa city 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 Annal s of Botany Company.