Sueli Maria da Silva
Campus Jataí, 2009
Abstract:
Due to its use in human and animal food and its high productive potential, maize is one of the most important cultivated and traded cereals in the world. However, for high productivity it is necessary to supply nutrients in adequate proportion. Nitrogen and potassium are the nutrients absorbed in greater proportion, with numerous functions in the physiological activities of the crop. Aimed to evaluate the effect of different doses of potassium and nitrogen on the activity of nitrate reductase enzyme in corn crop under greenhouse conditions. Five doses of nitrogen (0, 50, 100, 150 and 200 kg ha-1) and five doses of potassium (0, 40, 80, 120 and 160 kg ha-1) were used. Enzyme activity was estimated "in vivo" after the plants reached four fully unfolded leaves. The method was based on the principle that the amount of nitrite released by living tissue fragments in a buffer in the presence of a permanent agent and substrate reflects the potential activity of the enzyme. The activity of the nitrate reductase enzyme was significantly influenced by the interaction of nitrogen and potassium doses, where the interaction N = 100 kg ha-1 and k = 40 kg ha-1 provided the best averages of the experiment. From this dose, the increase in the supply of both nitrogen and potassium promoted reduction of enzymatic activity.
