Nitrate content and activities of nitrate reductase and glutamine synthetase by ionic strength, nitrate concentration, ratio of nitrate to ammonium in nutrient solution for culture of leaf lettuce and water dropwort
Lee, E.H.; Lee, B.Y.; Lee, Y.B.; Kwon, Y.S.; Lee, J.W.
Journal of the Korean Society for Horticultural Science 39(2): 161-165
The fresh weight of leaf lettuce (Lactuca sativa L.) and water dropwort (Oenanthe stolonifera DC.) was higher at 1.5S and 2.0S than in any other ionic strength in spring culture. The fresh weights were lowest at 0.5S in both crops. Nitrate contents, nitrate reductase and glutamine synthetase activities were highest at 2.0S in leaf lettuce with 4,330 mg cntdot kg-1 FW, 10.1 muM NO2- cntdot g-1 FW cntdot h-1 and 11.2 muM glu. cntdot g-1 FW cntdot h-1, respectively. Also water dropwort showed the same trend as leaf lettuce. In both leaf lettuce and water dropwort, fresh weights, nitrate contents, nitrate reductase and glutamine synthetase activities according to the nitrate concentrations in nutrient solution were higher at 13 meq cntdot L-1 than at another nitrate concentrations. Under the ratio of NO3- : NH4+ = 75 : 25, fresh weights of leaf lettuce and water dropwort were 59.8 and 46.9 g, respectively, which were the highest among the treatments except for 100 : 0 ratio. At 100 : 0 ratio, NO3- contents were highest with 3,845 mg cntdot kg-1 FW in leaf lettuce and 5,234 mg cntdot kg-1 FW in water dropwort. Activities of nitrate reductase and glutamine synthetase were also highest at 100 : 0 ratio.