Electrophoretic analysis of antioxidant enzymes activity under drought stress in winter wheat genotypes at tillering stage

Drought stress is one of the main stresses that inhibit the growth of plants. In this research, the effect of drought stress was studied on the activity of CAT, SOD and POX enzymes in three groups of drought sensitive, intermediate and tolerant winter wheat at tillering stage under normal irrigation (90% FC), mild drought stress (60% FC) and severe drought stress (30% FC) conditions. The experiment was conducted in factorial experiment based on completely randomized design with three replications and activity of three enzymes was recorded at tillering stage. The activity of all enzymes was measured by 7.5% polyacrylamide gel electrophoresis in leaf tissues. Four isozymes were identified for POX, one isozyme for CAT and two isozymes for SOD. The analysis of variance showed that drought stress had significant effect on the activity of all enzymes. Enzyme activity levels in most enzymes increased in severe drought stress than normal condition, so the activity of POX1, POX2, POX3 and POX4 isozymes increased 39, 86, 75 and 20 percent and CAT, SOD1 and SOD2, isozymes increased 31, 10 and 15 percent, respectively. The results indicated that among the studied enzymes, SOD isozymes had lower changes in activity and hadnt important role in plant protection under drought stress, whereas POX enzyme showed more important increment of activity under drought stress conditions. Thus the POX might have a key and effective role in increasing of wheat resistance under drought stress conditions.