Effect of cadmium and lead on growth, certain antioxidant enzyme activity, protein profile and accumulation of cadmium, lead and iron in Raphanus sativus and Eruca sativa seedlings

Egyptian Journal of Biology Vol.3 2001: 131-13

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

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: 7-1

Protection induced by external Ca2+ application on proline accumulation, ion balance, photosynthetic pigments, protein and ABA concentration of mustard seedlings (Sinapis alba L.) under salinity stress

The effect of external Ca2+ application of different concentration to salinity-treated (100 mM NaCl) mustard plant (Sinapis alba L.) was investigated in relation to ion uptake, proline, chlorophyll a&b, protein and ABA concentrations. Salinity treatment (100 mM NaCl) led to significant decreases in Ca2+& Kuptake and Chl. a&b contents, accompanied by significant increases in Na+ uptake, proline and ABA concentrations. Salinity treatment also induced the appearance of new protein bands. The most effective concentrations of CaCl2 treatment in protecting mustard plants against the adverse effect of NaCl salinity were 5, 10, and 15 mM CaCl2. This could be attributed to the effect of CaCl2 in decreasing ABA concentration, the synthesis of new polypeptides and increasing K+ and Ca2+ uptake. KEY WORDS: salinity, CaCl2, proline, protein, ABA. Egyptian Journal of Biology Vol.4 2002: 14-2