Gibberellins and Plant Reproduction

The involvement of the phytohormone gibberellin (GA) in land plant reproductive processes is ancient, but is best understood in flowering plants (angiosperms). GA acts in angiosperms to promote the transition from vegetative to reproductive development, and subsequent development of both male (stamen) and female (pistil) floral organs. Coordinating growth between these organs to promote successful fertilisation is a key regulatory function of GA. Its functions in female development are not well understood, but in stamens a number of downstream regulatory pathways have been determined. GA signalling directly regulates processes both in pollen development and in the surrounding anther tissues, particularly the tapetum. Female fertility also requires GA, which, while incompletely understood, regulates both pistil and ovule development. GA is a crucial trigger of fruit development upon fertilisation, and subsequently contributes to both the development of viable seeds and of fruiting structures.