EVALUATION OF NITROGEN-FERTILIZER AND INOCULATION WITH DIAZOTROPHIC BACTERIA ON THE BIOCHEMICAL BEHAVIOR OF THE MAIZE CULTIVAR NITROFLINT

The evaluation of nitrogen fertilizer and inoculation with diazotrophi c bacteria on the genetic and biochemical behavior of the maize (Zea m ays L.) cultivar Nitroflint were performed in two experiments, one in the field and the other in greenhouse. The experimental set up consist ed of a randomized blocks design with three replications and two evalu ation factors, inoculation (or not) with diazotrophic bacteria and nit rogen fertilizer levels (100 kg/ha of N and 10 kg/ha of N). In the fie ld experiment the following parameters were measured: grain production , total plant nitrogen (above ground), grain nitrogen and activities o f the enzymes nitrate reductase and glutamine synthetase. In the secon d experiment (greenhouse), fresh weight of the plant, glutamine synthe tase (transferase and synthetase) and nitrate reductase activities wer e determined for both leaf and root tissue. A bacterial count was made in three media, denominated LGI (semi-selective for Azospirillum amaz onense), JNFb (Herbaspirillum spp.) and NFb (Azospirillum spp.) for th e shoot and the root. Results of the field experiment showed an effect of N fertilizer on total N and grain production. The second experimen t (greenhouse) showed an effect of N fertilizer on all parameters meas ured 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.