Effect of Nitrate Uptake Kinetic with Different Ratios of Ammonium and Nitrate in Banana Seedlings

The characteristics of nitrate uptake kinetic in the solution of five ratios of ammonium and nitrate by modified depleting way treated with 0.2 mmol/L CaSO4 solution for three days were studied to discover the ammonium and nitrate nutrition properties of banana seedlings.The result showed that the nitrate uptake kinetic characteristics of all treatments with five ratios of ammonium and nitrate followed the enzyme kinetic model of Michaelis-Menten.Increasing ammonium ratio remarkably influenced Vmax and Km;Vmax would be reduced more to the Hoagland solution adding 10% ammonium than that in placement of 10% ammonium with 10% nitrate,although Km had no distinct difference between these two treatments.The nitrate uptake rate would be reduced in soil of 100% nitrate treated with increasing ammonium ratios.The nitrate affinity.would be decreased treated with 10% more ammonium,while that for the 25% ammonium treatment was in the opposite direction.The nitrate uptake for banana seedlings belonged to low affinity system.