Molecular and genetic aspects of flower senescence

Abstract

Purpose of the review: T his review gauges the effects of recent research into m olecular and genetic flower senescence on the devel opment of postharvest cut-flower technologies. Recent findings: Et hylene, cytokinin, sugars, cysteine proteases and other hydrolytic enzymes influence senescence in cut flowers thro ugh a complex series of interactions that are being activel y investigated, but have yet to be fully understood. Senescence rel ated genes have now been isolated and characterised in a number of model flower crops (eg, petunia, arabidopsis) and cut flower s pecies (eg, Alstroe meria, car nation, Iris, San dersonia). T he expression of these genes, tog ether with a full understanding of the function of encoded proteins, is progressing. To date, new technologies for extending the postharvest life of cut flowers h ave been found through manipu lation of ethylene biosynthesis and sensitivity. The challenge is to find avenues for maintaining q uality and extending the vase life of ethylene-insensitive cut flowers. Directions for future research: Solving the functional significance of genes that have been linked to flower senescence will fu rther advance our understanding of the relevance of proteolysis, sugars, membrane integrity and cell wall modifications that o ccur during floral organ senescence. In turn, information on genetic co ntrol points of cut flower senescence will enable develo pment of new avenues for manipulation and extension of the posth arvest life of cut flowers (either n ew cultivars or vase-life treatm ents). Keyw ords: cut flower; senescence; ethylene; cytokinin; proteases; g ene; sugars; cell wall; membranes; lipases