Effect of high temperature and excessive light on glutathione content in apple peel

Abstract

The present experiment was conducted to examine the changing patterns of glutathione (GSH) contents in apple peel stressed by high temperature and excessive solar radiation. By comparing the parameters of temperature and light conditions where fruits grow with the GSH contents in them, the mutual relationship was disclosed. Meanwhile, the changes of antioxidant capacity of fruits stressed at different levels were studied under artificially controlled conditions in a laboratory. Also, the effect of applying various types of exogenous substances was evaluated on endogenous GSH contents. The results indicated that within a certain range, a positive correlation was found between the stressed extents to which fruits were subject by high temperature and excessive light, and GSH contents in fruit peel. Moreover, fruits on southwest (SW) exposure contained a very significantly higher amount of GSH than those on other exposures. In laboratory experiments, it was proved that fruit GSH contents increased with temperatures within a certain range but they declined beyond a given limit. The temperature rising modes had a great influence on fruit GSH contents, and gradual temperature increase was favorable to an increase of antioxidant capability in fruit peel, thus providing a theoretical basis for exerting appropriate acclimation on fruits. It was also documented that application of four exogenous formulations could significantly increase the endogenous GSH contents, among which AsA (ascorbit acid) + BA (benzoic acid) and SA (salicylic acid) treatments exhibited better results, 33.97% and 31.81% higher than the control, respectively.