Effect of Foliar Nitrogen Application on Nitrogen Metabolism, Water Status, and Plant Growth in Two Maize Cultivars under Short-term Moderate Stress

Two contrasting maize (Zea mays L.) cultivars, i. e. 'Shaandan 9' (S-9) and 'Shaandan 911'(S-911) were investigated by examining foliar nitrogen (N) modulation of N metabolism, water status and plant growth under short- term moderate water stress (SMWS). On 10th day of SMWS, dry matter (DM), relative water content (RWC) and nitrate reductase activity (NRA) were significantly decreased, whereas concentrations of free proline (FP), glycinebetaine (GB) and soluble protein (SP) were increased in leaves of both cultivars. Cultivar S-9 maintained greater DM, RWC and these N metabolism traits than S-911 during SMWS. Foliar N application much more raised DM, RWC, NRA, and concentrations of all solutes measured under SMWS above control. These positive effects were more pronounced in S-911 than those in S-9 during SMWS. Greater correlations were performed amongst all parameters under SMWS than control. Hence, we suggest that foliar N should be firstly applied to drought sensitive cultivars under drought.