EFFECT OF FOLIAR APPLICATION ON THE HERBICIDE STOMP ON NITRATE REDUCTASE IN THE LEAVES OF Gossypium hirsutum L.

Foliar application of stomp resulted in drastic diminishment of three parameters in leaves of young plants of cotton. The higher dose of the herbicide (15ppm) provoked reduction in nitrate reductase activity by 46% , 57% after 5, 10 and 15 days respectively. The same dose lowered the total soluble sugars by 40% , 64% and 73% after 5, 10 and 15 days respectively. The nitrate content showed similar pattern and decreased progressively with increasing the dose of the herbicide throughout the run of the investigation. The negative effect of the herbicide on these parameters could be attributed to reduction in carbon assimilation. Inadequate supply of sugars reduces nitrate uptake and reduction and consequently nitrate reductase being a substrate inducible enzyme is negatively affected.