Flower Senescence

Current knowledge indicates that flower petal senescence is a form of programmed cell death called vacuolar cell death. In this process the cell first degrades most of the cytoplasm and organelles using an array of degradative enzymes present in the vacuole for reuse of the nutrients. The final step in this process is disruption of the vacuolar membrane by which the hydrolytic enzymes are released to 'finish' what is left of the cell. In ethylene-sensitive flowers, ethylene triggers the cell death process, and flower life can be greatly extended by blocking production or perception of ethylene. This has led to development of very effective chemical treatments with broad application and molecular genetic strategies of potential commercial value. In ethylene-insensitive flowers, the senescence program may be similar to that of ethylene-induced senescence. However, the hormonal or developmental events that trigger the cell death processes in ethylene-insensitive species have not been identified. Many genes and transcriptional regulators with putative roles in senescence have been identified using transcriptomic approaches. Testing their functions in transgenic plants is necessary to design new concepts and treatments for prolonging the life of flowers.