Abstrait

Effect of silicon on the activity of peroxidase, polyphenol oxidase and nitrate reductase in cowpea and wheat

N.C.Aery, Manju Mali

Nutrient culture experiments were conducted to study the effect of various doses (25, 50, 100, 200, 400 and 800 µg g-1) of silicon on the activity of certain enzymes (peroxidase, polyphenol oxidase and nitrate reductase) in the leaves of wheat and cowpea. Lower doses of silicon (25-200 µg g-1) significantly decreased the activity of peroxidase and polyphenol oxidase enzymes. The increasing concentrations of silicon (400-800 µg g-1) resulted in a concomitant increase in the activity of peroxidase and polyphenol oxidase in both the test crops. Nitrate reductase showed a different trend from that of peroxidase and polyphenol oxidase in both the test crops. A significant increase in nitrate reductase activity was observed at lower additions of silicon whereas higher doses of silicon (400-800 µg g-1) resulted in a decrease in nitrate reductase activity in both the test crops suggesting the involvement of Si in the enzymatic activities of plants.