Study On Physiological Effects And Thermotolerance Induction Of Apple Under High Temperature Stress

The effect of high temperature on the electrolytic leakage of membrance, the content of malondialdehyde (MDA), the activities of antioxidant enzymes, and the content of antioxidants of apple were studied and the treatments with Ca~2+, Salicylic acid and ascorbic acid were taken to induce the thermotolerance of apple under high temperature stress in this thesis. The physiology and biochemical mechanism of high temperature on apple and the treatment of Ca~2+, Salicylic acid(SA) and ascorbic acid(ASA) on apple under high temperature stress were also discussed. All aboved provided the base theory for cultivation and breeding of apple.The results showed that the electrolytic leakage of membrane was amplified, and the content of MDA were accumulated in apple under high temperature stress. The activities of superoxide dimutase(SOD), catalase(CAT), peroxidease(POD) and ascorbic peroxidase(APX) were decreased during the first period of high temperature stress and then were activated, lately the activities were decreased gradually with long time stress of high temperature. Ascorbic acid(ASA) content was increased during the first period of high temperature stress and then was decreased. The content of glutathione(GSH) was increased during all the stress period. When treated with Ca~2+, SA and ascorbic ASA, the electrolytic leakage of membrane and MDA content was lower than those in control under high temperature stress, the antioxidant enzymes and ASA content of apple were higher than those in the control, but the GSH content was decreased. Compared to the control, the apple treated with Ca~2+, SA and ASA maintain higher levels of antioxidant enzyme activeties, inhibited the electrolytic leakage of membrane, and diminished the content of MDA in apple under high temperature stress.