Behavior of nitrate enzyme reductase in upland riceunder different doses and sources of nitrogen

Abstract

Nitrate (NO3 - ) is considered the most important source of nitrogen for plant growth. To become available to plants, it is necessary for nitrate to be reduced through the enzyme nitrate reductase (N.R). Given the complexity of understanding N.R in plants, more specific studies involving this enzyme are needed for each crop, with upland rice being a crop with great influence of this enzyme. Thus, the objective of this work was to evaluate the behavior of the nitrate reductase enzyme in response to different doses and nitrogen sources in upland rice. The experiments were conducted in an experimental area belonging to the Federal University of Lavras, in plots consisting of 4 lines of 3 linear meters, spaced between them with 0.35 m, totaling 4.2 m2 per plot. The experiments were conducted using the DBC, with three replications, in a factorial scheme (4x4), with the first factor being nitrogen doses (D.N) and the second factor being sources of nitrogen (S.N), constituting 16 treatments. The characteristic evaluated in the two harvests was the nitrate reductase activity, through the in vivo test in the laboratory. It can be concluded with the results obtained that there were gains in activity of nitrate reductase with the increase in D.N, as well as its greater activity in younger stages of upland rice plants. The different doses and sources of N did not statistically influence the activity of nitrate reductase in rice plants, probably due to the genotype of each cultivar varying in terms of its efficiency of absorption of N which, consequently, will influence the activity of nitrate reductase.