The effect of light intensity and zinc deficiency on antioxidant enzyme activity, photosynthesis of corn.

Studies about zinc deficiency have shown that oxidative damages of Zn deficient plant cells results from attack by reactive oxygen species (ROS). High light intensity also leads to oxidative stress and increases the ROS in plants. To mitigate the oxidative damage by ROS, antioxidant systems including oxidative enzymes in plants has been developed. A factorial experiment was conducted in completely-randomized design (CRD) with two factors Including zinc-deficient and zinc-sufficient (0 and 16 μM, Respectively) and two light levels, including low and high light (50 μmol m -2 s -1 and 200 μmol m -2 s -1 , respectively) cultured in perlite. In this study Photosynthetic gas exchange parameters, the activity of some antioxidant enzymes such as superoxide dismutase, catalase, peroxidase (POD, CAT, SOD), hydrogen peroxide metabolit (H2O2) and total shoot protein were measured. The results showed that Zn deficiency under low light intensity refers to decrease in photosynthesis, transpiration and stomatal conductance, whereas refers to increase stomatal resistance. Zinc deficiency under low light intensity also reduced the activity of antioxidant enzymes, superoxide dismutase and catalase and increased the activity of peroxidase and the methabolit of hydrogen peroxide.