נגישות
menu      
חיפוש מתקדם
Physiologia Plantarum
Michaeli, R., Department of Postharvest Science of Fresh Produce, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Philosoph-Hadas, S., Department of Postharvest Science of Fresh Produce, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Riov, J., Kennedy-Leigh Centre for Horticultural Research, Faculty of Agriculture, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
Shahak, Y., Institute of Horticulture, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Ratner, K., Institute of Horticulture, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Meir, S., Department of Postharvest Science of Fresh Produce, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
The role of increased oxidation induced by successive stresses of chilling and high light in the induction of leaf abscission was studied in Ixora coccinea plants in relation to auxin metabolism and oxidative processes. Exposure of plants following dark chilling (7°C for 3 days) to high light (500-700 μmol m-2 s-1 photosynthetically active radiation) for 5 h at 20-25°C enhanced chilling-induced leaf abscission. This abscission was inhibited by pretreatment with the antioxidant butylated hydroxyanisole, α-naphthaleneacetic acid or the ethylene action inhibitor, 1-methylcyclopropene. The oxidative processes initiated during the low light period following the dark chilling period, such as indoleacetic acid (IAA) decarboxylation and lipid peroxidation, were further enhanced by subsequent exposure to high light. Photoinhibition, expressed by the reduction of the chlorophyll fluorescence parameter Fv/Fm, was evident following exposure to high light, irrespective of the temperature of the pretreatment, but this reduction persisted only in chilled plants. This suggests that oxidative processes generated during and after the chilling period might have inhibited the recovery from photoinhibition. The chilling stress under darkness induced a 60% reduction in superoxide dismutase (SOD) activity and significant increases (130-600%) in the activities of several other antioxidative enzymes. These data suggest that the chilling-induced reduction in SOD activity may well be responsible for the increase in the oxidative stress induced by the subsequent light treatment, as expressed by the increased enzymatic activities. Taken together, this study provides further support for the involvement of oxidative processes in the events occurring in tissues exposed to sequential chilling and light stresses, leading to reduction in free IAA content in the abscission zone and to leaf abscission.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Chilling-induced leaf abscission of Ixora coccinea plants. III. Enhancement by high light via increased oxidative processes
113
Michaeli, R., Department of Postharvest Science of Fresh Produce, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Philosoph-Hadas, S., Department of Postharvest Science of Fresh Produce, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Riov, J., Kennedy-Leigh Centre for Horticultural Research, Faculty of Agriculture, Hebrew University of Jerusalem, PO Box 12, Rehovot 76100, Israel
Shahak, Y., Institute of Horticulture, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Ratner, K., Institute of Horticulture, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Meir, S., Department of Postharvest Science of Fresh Produce, ARO, Volcani Center, PO Box 6, Bet Dagan 50250, Israel
Chilling-induced leaf abscission of Ixora coccinea plants. III. Enhancement by high light via increased oxidative processes
The role of increased oxidation induced by successive stresses of chilling and high light in the induction of leaf abscission was studied in Ixora coccinea plants in relation to auxin metabolism and oxidative processes. Exposure of plants following dark chilling (7°C for 3 days) to high light (500-700 μmol m-2 s-1 photosynthetically active radiation) for 5 h at 20-25°C enhanced chilling-induced leaf abscission. This abscission was inhibited by pretreatment with the antioxidant butylated hydroxyanisole, α-naphthaleneacetic acid or the ethylene action inhibitor, 1-methylcyclopropene. The oxidative processes initiated during the low light period following the dark chilling period, such as indoleacetic acid (IAA) decarboxylation and lipid peroxidation, were further enhanced by subsequent exposure to high light. Photoinhibition, expressed by the reduction of the chlorophyll fluorescence parameter Fv/Fm, was evident following exposure to high light, irrespective of the temperature of the pretreatment, but this reduction persisted only in chilled plants. This suggests that oxidative processes generated during and after the chilling period might have inhibited the recovery from photoinhibition. The chilling stress under darkness induced a 60% reduction in superoxide dismutase (SOD) activity and significant increases (130-600%) in the activities of several other antioxidative enzymes. These data suggest that the chilling-induced reduction in SOD activity may well be responsible for the increase in the oxidative stress induced by the subsequent light treatment, as expressed by the increased enzymatic activities. Taken together, this study provides further support for the involvement of oxidative processes in the events occurring in tissues exposed to sequential chilling and light stresses, leading to reduction in free IAA content in the abscission zone and to leaf abscission.
Scientific Publication
You may also be interested in