Compostos nitrogenados, proteínas e aminoácidos em milho sob diferentes níveis de silício e deficiência hídrica

Abstract

Maize (Zea mays L.), from family Poaceae is one of the most important plants in Brazil, being produced in various regions of the country. The use of Silicon (Si) in the agriculture has been shown to be effective against various abiotic factors such as water deficit. The objective of this work was to study the behavior of nitrogen compounds, proteins and total soluble amino acids in maize plants under different levels of Si and water stress. The experiment was conducted in a greenhouse at the Federal Rural University of Amazonia - Captão Poço, using the PZ 242 maize variety, from the 2010 crop season. A completely randomized design (CRD) in a 2 x 4 factorial scheme was used, with seven replications. Treatments were control (without water deficit), water deficit without Si supply, and water deficit with four doses of Si supplied as sodium metasilicate (0.5, 1.0, 1.5 and 2.0 mm Si). Water stress caused alterations in relative water content and biochemical processes in all studied biochemical processes, such as nitrate reductase activity, and concentration of proteins, amino acids, free ammonium and nitrate. However, satisfactory results were observed when Si was applied in plants exposed to water deficit,, particularly at concentrations of 0.5 and 1.0 mm. Key words: Zea mays; nitrogen fertilization; urea; sulfur source.