The objectives of the study were 1) to determine the combined effects of microwave pretreatment and cadmium stress on wheat seedlings and 2) to evaluate the effect of seed pretreatment by microwaves on protecting wheat from cadmium (CdCl2) stress damage using plant morphological and physiological indices.
Seeds were exposed to microwaves for 0, 5, 10 and 15 s (each n=1000) and when the seedlings were 7 days old (with one fully expanded leave), they were treated with 150 µM CdCl2 solution for 10 days. On days 2, 4, 6, 8 and 10 leaves and roots were sampled for various analysis.
|Exposure duration||continuous for 5 s, 10 s or 15 s|
CdCl2 treatment alone reduced plant height, root length, dry weight, ascorbate and glutathione concentrations and the enzyme activities of peroxidase, superoxide dismutase, catalase, ascorbate peroxidase, and enhanced the concentration of malondialdehyde, hydrogen peroxide and the production of superoxide when compared with the control.
However, seeds with microwave pretreatment for 5 or 10 s conferred a tolerance to cadmium stress in wheat seedlings by decreasing the concentration of malondialdehyde and hydrogen peroxide, the production of superoxide and increasing the enzyme activities of peroxidase, superoxide dismutase, catalase, ascorbate peroxidase and ascorbate and glutathione concentration. Therefore, antioxidative enzymes and antioxidative compounds may be involved in tolerance of wheat seedlings to cadmium stress. The findings also showed that the microwave exposure had a positive physiological effect on the growth and development of cadmium stressed seedlings (significant increase of root length and dry weight).