Role of the ascorbate-glutathione cycle during senescence and programmed cell death in <i>Phaseolus</i> cotyledons

Abstract

Programmed cell death is an integral part of normal plant development including leaf senescence. This study investigated the response of some component of ascorbate-glutathione cycle, chlorophylls.a & b, protein content, and membrane leakage during the developmental stages of Phaseolus cotyledons from imbibition till cotyledon death. It was found that during cotyledon senescence, lipid peroxidation increased while the enzymic and nonenzymic antioxidants were decreased, particularly at the final stage (cotyledon death). Moreover, chlorophylls a & b and protein contents were decreased. It could be concluded that natural senescence of Phaseolus cotyledons exhibited a pattern of programmed cell death underlined by increase in membrane leakage levels.


KEY WORDS: chlorophylls, protein, membrane leakage, development, Phaseolus vulgaris


Egyptian Journal of Biology Vol.4 2002: 7-13