GSH Improves Tolerance To Water Deficit Stress In Cut Rose And Its Effect On Antioxidative Enzyme Activity

This work was aimed to investigate the effect of GSH on tolerance to water deficit stress. Cut rose (Rosa hybrida) 'Samantha' was pretreated with GSH and BSO to increase or decrease GSH content in flowers, respectively, and effect of change in GSH content on cut rose exposed to 24 h of water deficit stress was measured. Potent GSH concentration was determined and effective concentration of BSO, a reagent that decreases GSH content, was further determined. The adequate concentrations of GSH and BSO were used to pretreat the flowers, and water potential, MDA content, SOD, POD, CAT, APX, GPX and GR activity, GSH and AsA content were assayed to determine the effect of regulating GSH content on antioxidative system and tolerance to water deficit stress. The results showed:1. 24h water deficit stress accelerated the senescence process, and vase life was shortened 50%. Water recovery rate was lower and ornamental value was lost when the flowers were stressed for more than 36h.2. Tolerance to water deficit stress was markedly increased by GSH pretreatment, and the improvement effect increased with increasing GSH content if it was no more than 2 mmol/L. No better effect was found when the concentration was more than 2 mmol/L. 2 mmol/L GSH was determined as the adequate concentration for GSH pretreatment.3. GSH content decreased after BSO pretreatment, and the decrease was greater with increasing BSO content, and no significant decrease in total GSH content was found when BSO content was more than 2 mmol/L. Decrease in GSH content decreased the tolerance to water deficit stress, shortened vase life, inhibited flower opening and accelerated wilting process.4. Compared with 'Stress control', water potential was significantly increased, MDA content markedly decreased and GSH content and GR activity was effectively increased by 2 mmol/L GSH. Ideal opposite evidence was obtained by 2 mmoi/L BSO pretreatment.5. In response to water deficit stress, all antioxidative enzymes increased in the early stage of water deficit stress, and they decreased when stress time was prolonged, increased during water recovery period and decreased again during vasing; GR, GPX, SOD and APX activity and AsA content was increased, POD and CAT were not greatly influenced by GSH pretreatment and thereby decreased MDA content. BSO pretreatment markedly decreased GR, GPX and SOD activity during stress period and no great decrease in GR, POD and APX activity was found and GR, GPX, SOD, POD, CAT and APX activity was lower than those of stress control.The above results showed 2 mmol/L GSH could effectively increased tolerance to water deficit stress in cut rose 'Samantha', and the effect was through increasing antioxidative enzyme activity...