Polyamines and plant morphogenesis

Alterations in free and conjugated polyamines (PAs) and the enzymes involve d in their biosynthesis, namely arginine decarboxylase, ornithine decarboxy lase and S-adenosyl methionine decarboxylase have been reported to occur du ring cell division, growth, embryogenesis and rhizogenesis in an array of p lant materials. However, the relationship, if any, between them and all the se processes has not yet been established. It seems that specific PAs at sp ecific concentration ranges are required during critical stages of growth a nd morphogenetic events. Furthermore, the effects of PA biosynthesis inhibi tors vary considerably at different developmental stages of the same tissue . The present review deals with the available information about the possibl e role of PAs in aforesaid physiological processes.