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

ABSTRACT

Two contrasting maize (Zea mays L.) cultivars, i.e. ‘Shaandan 9’ (S₉) and ‘Shaandan 911’(S₉₁₁) 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 S₉ maintained greater DM, RWC and these N metabolism traits than S₉₁₁ 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 S₉₁₁ than those in S₉ 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.

Keywords:

• nitrate reductase activity
• osmotic organic nitrides
• maize cultivar
• relative water content
• water stress

ACKNOWLEDGMENTS

This work was jointly supported by China Postdoctoral Science Foundation (20070421133) and the Key Project (30230230) of the National Natural Science Foundation of China (NSFC) and the Foundation of State Key Laboratory of Soil Erosion and Dryland Farming (10501-HZ06). The authors would like to take the opportunity to thank Dr. H. A. Mills, all editors and reviewers for their critical reading this manuscript.