Microwave pretreatment can enhance tolerance of wheat seedlings to CdCl2 stress

In order to determine the role of microwave in cadmium stress tolerance of wheat (Triticum aestivum L.), seeds were exposed to microwave radiation for 0, 5, 10 and 15 s (wavelength 125 mm, power density 126 mW cm(-2), 2450 MHz), and when the seedlings were 7 d old (with one fully expanded leaves), they were treated with 150 mu M CdCl2 solution for 10 d. Changes in a number of physiological and biochemical characteristics were measured and used as indicators of the protective capacity of microwave radiation in this experiment. Our results showed that 150 mu M CdCl2 treatment reduced plant height, root length, dry weight, AsA and GSH concentration and the activities of SOD, POD, CAT and APX, enhanced the concentration of MDA, H2O2 and the production rate of O-2(-) when compared with the control. However, seeds with microwave pretreatment 5 or 10 s conferred tolerance to cadmium stress in wheat seedlings by decreasing the concentration of MDA and H2O2, the production rate of O-2(-) and increasing the activities of SOD, POD, CAT, APX and AsA and GSH concentration. Therefore, antioxidative enzymes and antioxidative compounds may participate in tolerance of wheat seedlings to cadmium stress. The results also showed that the microwave radiation had a positive physiological effect on the growth and development of cadmium stressed seedlings. This is the first investigation reporting the use of microwave pretreatment to enhance cadmium stress tolerance of wheat. (C) 2010 Elsevier Inc. All rights reserved.