Water stress affects deeply plant cell metabolism. The objective of this work was to quantify the effects of water deficits and its recovery on the performances of nitrogen metabolism enzymes: nitrate reductase (NR), glutamine sintethase (GS) and glutamate sintase (GOGAT) and an accumulation of proline in maize genotypes BR 2121 and BR 205. The trial was carried out in greenhouse, by using pots with 14.3kg of soil. The treatments performed were a combination of two genotypes and four intervals among irrigation (1, 3, 5 and 7 days). On the day in which the treatments were evaluated (49 days after emergency), there was irrigation on the treatments with intervals of 3 and 7 days, therefore those treatments were considered as light and severe recovery of water deficit, respectively. The extractions and analysis were performed by taking the third leaf completely expanded from top to down. The activities of enzymes did not differ among water deficit treatments, control and recovery of severe stress showed higher enzymatic activity than control. The accumulation of free proline in the leaves increased with deficit and responded to recovery of water deficit by reducing its content. In general, the enzimatic activity and the proline accumulation showed inverse answers within treatments.
nitrogen; water deficit; proline; nitrate reductase; GS; GOGAT
