Evaluation of nitrogen fertilizer and inoculation with diazotrophic bacteria on the biochemical behavior of the maize cultivar Nitroflint

Abstract

The evaluation of nitrogen fertilizer and inoculation with diazotrophic bacteria on the genetic and biochemical behavior of the maize (Zea mays L.) cultivar Nitroflint were performed in two experiments, one in the field and the other in greenhouse. The experimental set up consisted of a randomized blocks design with three replications and two evaluation factors, inoculation (or not) with diazotrophic bacteria and nitrogen fertilizer levels (100 kg/ha of N and 10 kg/ha of N). In the field experiment the following parameters were measured: grain production, total plant nitrogen (above ground), grain nitrogen and activities of the enzymes nitrate reductase and glutamine synthetase. In the second experiment (greenhouse), fresh weight of the plant, glutamine synthetase (transferase and synthetase) and nitrate reductase activities were determined for both leaf and root tissue. A bacterial count was made in three media, denominated LGI (semi-selective for Azospirillum amazonense), JNFb (Herbaspirillum spp.) and NFb (Azospirillum spp.) for the shoot and the root. Results of the field experiment showed an effect of N fertilizer on total N and grain production. The second experiment (greenhouse) showed an effect of N fertilizer on all parameters measured and inoculation was effective on glutamine synthetase activity of the root by transferase reaction. A correlation was obtained between root glutamine synthetase activity and bacterial growth in LGI.