Response of Corn Seedlings (Zea mays L.) to Different Concentrations of Nitrogen in Absence and Presence of Silicon

Corn plants are highly demanding of nitrogen and the application of silicon has been studied because it minimizes stress from different natures, and for the better utilization of some nutrients by the plants. Thus, the response of the plant to N can be increased by its association with silicon. The present study had the objective to evaluate the dry matter production, accumulation of nitrogen and silicon in the shoots of the plants as well as the physiological variables in corn culture, as a function of nitrogen concentrations in the nutrient solution in the absence and presence of silicon. Treatments consisted of nitrogen concentrations (1.4, 3.6, 7.1, 14.3, and 28.6 mmol L -1 ) in the absence and presence (1.8 mmol L -1 ) of silicon, silicic acid being used as the silicon source, arranged according to a completely random design with four replications. Corn plants (AG 1051) were cultivated in pots (800 mL). At 10 and 20 days after application of the treatments the dark green color index was examined and 21 days after application of the treatment the nitrate reductase activity, accumulation of N and Si, accumulation of proline and dry matter were evaluated. Significant interactions were observed only for dark green color index. Adding silicon resulted in higher N and Si concentrations in the plant shoots, and higher nitrate reductase activity with resulting higher shoot dry mass production, although it did not influence proline content in corn plant leaves.