TY - JOUR
T1 - Adjustment to low light intensity enhances susceptibility of bean leaves to oxidative stress
AU - Shainberg, Oren
AU - Rubin, Baruch
AU - Rabinowitch, Haim D.
AU - Libal-Weksler, Yael
AU - Tel-Or, Elisha
PY - 1999/9
Y1 - 1999/9
N2 - We studied the effect of a short term shading on the activity of the antioxidative system in primary leaves of Phasedus vulgaris (cv. Pinto) and the response of the shaded beans to subsequent oxidative stress. Shaded bean leaves demonstrated a 35 % decrease in activity and concentration of glutathione reductase (GR, EC 1.6.4.2) and reduced glutathione (GSH) and a 30 % decrease in concentration of chloroplastic CuZn-superoxide dismutase (SOD, EC 1.15.11). No difference was observed in activities of ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (EC 1.11.1.6) and the concentration of cytosolic CuZn-SOD. Two days shading (20 % of that of daylight) of bean plants resulted in increased sensitivity to methyl viologen and SO2 as compared to unshaded control plants but there was no difference in the sensitivity to ozone. Shaded leaves suffered marked increase in ion leakage and water losses, and developed more necrotic lesions as compared to the control leaves. Our results show that in beans, even a short transition of plants from high to low light intensity, decreases the activity of chloroplastic antioxidative mechanisms that are needed to counteract subsequent oxidative stress.
AB - We studied the effect of a short term shading on the activity of the antioxidative system in primary leaves of Phasedus vulgaris (cv. Pinto) and the response of the shaded beans to subsequent oxidative stress. Shaded bean leaves demonstrated a 35 % decrease in activity and concentration of glutathione reductase (GR, EC 1.6.4.2) and reduced glutathione (GSH) and a 30 % decrease in concentration of chloroplastic CuZn-superoxide dismutase (SOD, EC 1.15.11). No difference was observed in activities of ascorbate peroxidase (APX, EC 1.11.1.11) and catalase (EC 1.11.1.6) and the concentration of cytosolic CuZn-SOD. Two days shading (20 % of that of daylight) of bean plants resulted in increased sensitivity to methyl viologen and SO2 as compared to unshaded control plants but there was no difference in the sensitivity to ozone. Shaded leaves suffered marked increase in ion leakage and water losses, and developed more necrotic lesions as compared to the control leaves. Our results show that in beans, even a short transition of plants from high to low light intensity, decreases the activity of chloroplastic antioxidative mechanisms that are needed to counteract subsequent oxidative stress.
KW - Beans
KW - Glutathione
KW - Glutathione Reductase
KW - Light intensity
KW - Methyl viologen
KW - Oxidative stress
KW - Phaseolus vulgaris
KW - SO
KW - Superoxide dismutase
UR - http://www.scopus.com/inward/record.url?scp=0032831568&partnerID=8YFLogxK
U2 - 10.1016/S0176-1617(99)80122-9
DO - 10.1016/S0176-1617(99)80122-9
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AN - SCOPUS:0032831568
SN - 0176-1617
VL - 155
SP - 393
EP - 398
JO - Journal of Plant Physiology
JF - Journal of Plant Physiology
IS - 3
ER -