The Effects Of Paclobutrazol On Diosgenin Synthesis, Reactive Oxygen Metabolism And Lipid Peroxidation In Dioscorea Zingiberensis Wright Plants

Paclobutrazol (PBZ), which is a new and effective plant growth regulator, has been put into use very widely. This paper studied the effects of paclobutrazol on diosgenin synthesis, reactive oxygen metabolism and lipid peroxidation in Dioscorea zingiberensis Wright plants. The main results were as follows:1. The effects of various concentrations (25, 50, 100, 200 and 400mg/L) of Paclobutrazol (PBZ) on the level of diosgenin in tubers of China endemic species Dioscorea zingiberensis Wright were observed. The results show that diosgenin synthesis was stimulated by PBZ, and the best result was in the case of 100mg/L treatment in which the diosgenin level was increased by 56.5% than control.2. This paper further studied the effects of various concentrations of PBZ on reactive oxygen metabolism and lipid peroxidation in Dioscorea zingiberensis Wright leaves under normal growth condition, the results show that 25, 50, 100,200, 400mg/L PBZ-treated Dioscorea zingiberensis Wright leaves were all decreased superoxide anion radical (O2-) production rate, stimulated an increment in the activities of superoxide dismutase (SOD), catalase (CAT), puaiacol peroxidase (POD), and ascorbic acid peroxidase (APX) activity, reduced malondialdehyde (MDA) content, and promoted the synthesis of soluble protein and chlorophyll. From the results, we can also see that 100 mg/L PBZ-treated is the best effective than the others.3. Drought brought about over production of reactive oxygen species (ROS) in Dioscorea zingiberensis Wright leaves, measured as an increment in O2-. production rate, MDA and free proline content and electrolytic relative exosmosis rate; an decrement in the activities of SOD, CAT, POD, APX activity and soluble protein and chlorophyll contents. However, after PBZ treatment, the changes above were maintained to a lower degree than their corresponding controls after exposure to drought stress, this indictated that PBZ-treated had elevated stress-resistance in Dioscorea zingiberensis Wright plants.