Molybdenum Application Regulates Oxidative Stress Tolerance in Winter Wheat Under Different Nitrogen Sources

Molybdenum (Mo), an essential microelement, may enhance the oxidative stress tolerance in plants. However, the efficacy of Mo might be variable with different forms of nitrogen (N) fertilizer. The present study was conducted to investigate the role of Mo application in regulating oxidative stress tolerance in winter wheat under different N sources. A hydroponic study was carried out comprising of two winter wheat cultivars '97003' and '97014' as Mo efficient and Mo inefficient, respectively, under two Mo levels (0 and 1 mu M) and three different N sources (NO3 & x336;, NH4NO3, or NH4+). Winter wheat plants supplied with different N sources accumulated superoxide anions (O-2(-)), and malonaldehyde (MDA) contents in the order of NH4+ > NO3 & x336; > NH4NO3, suggesting that sole application of either N sources, especially sole NH(4)(+)source, may induce oxidative stress in winter wheat. However, Mo application decreased the MDA contents by 20.02%, 15.11%, and 25.89% in Mo-efficient cultivar and 30.75%, 23.79%, and 37.76% in Mo-inefficient cultivar under NO3 & x336;, NH4NO3, and NH(4)(+)sources, respectively, while increased antioxidant enzyme activities and carotenoids and abscisic acid (ABA) contents up-regulated the expressions ofTaAOandTaAba3genes. Mo application regulated oxidative stress tolerance in winter wheat under different N sources through enhancing ABA production and ROS-scavenging enzymes. Mo-efficient '97003' winter wheat cultivar possesses a wider range of adaptability to withstand Mo-deficient conditions than Mo-inefficient '97014' cultivar.