Control of intracellular glutathione and its effect on ultraviolet radiation-induced K+ efflux in cultured rose cells |
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Authors: | A. J. HUERTA T. M. MURPHY |
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Affiliation: | Department of Botany, University of California, Davis, California 95616, U.S.A. |
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Abstract: | Abstract Modification of the ‘intracellular concentration of reduced glutathione’ (IC-GSH) affected the response of cultured rose cells (Rosa damascena) to ultraviolet radiation (UV)-induced leakage of K+. High IC-GSH induced by incubation of cells in 10 mol m?3 GSH (IC-GSH increased linearly with time from 20 to about 600 μmol g?1 in 61.2 ks) caused cells to become significantly less sensitive to UV. Low IC-GSH induced by treatment with 1 mol m?3 buthionine sulphoximine (BSO) plus 1 mol m?3 diethylmaleate (DEM) (IC-GSH decreased from 20 to about 3 μg g?1 in 61.2 ks) reduced, rather than increased, the UV-sensitivity of the cells. However, treatment with DEM also induced a large transient K+ leakage; and treatment with BSO induced a slight leakage. The K+ leaked was recovered by 3.24 ks. Following K+ recovery, the DEM-treated cells showed almost complete insensitivity to UV, and BSO-treated cells showed a slightly reduced sensitivity to UV. These results are in agreement with our previous findings that other treatments (heat, cycloheximide, UV), which also cause a transient leakage of K+, also reduce the induction of K+ leakage by a subsequent UV treatment. We conclude that high IC-GSH may play a role in protecting plant cells from UV-induced K+ leakage. Increased UV-sensitivity with low ICGSH was not observed, we believe, because of the transient K+ leakage, though the mechanism of reduced sensitivity to UV induced by transient leakage of K+ is not known at this time. Treatment with UV did not reduce the IC-GSH, showing that this is not the mechanism by which UV induces K+ leakage. |
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Keywords: | Rosa damascena Rosaceae glutathione ultraviolet radiation potassium leakage cultured cells |
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