Optimization of Water-Nitrogen Interaction Pattern Improves Maize Growth and Yield by Regulating Root Development

Abstract

Water scarcity leads to incomplete root development in spring maize (Zea mays L.) in cold semi-arid regions, inhibiting growth and decreasing yield. Limited knowledge exists regarding whether root distribution can be optimized by regulating different water-nitrogen (N) interactions to improve nutrient uptake, and maize yield. A 2-year experimental trial was conducted in this present study to reveal the influence of N under four water conditions on root distribution, maize growth and yield, osmotic adjustment. Compared with S1-N300, CK-N300 exhibited growth performance by plant height (9.2 cm), stem thickness (1.4 mm), and ear position height (4.6 cm) and S3-N300 reduced the 25.9 cm, 3.8 mm and 3.9 cm. Moreover, CK-N300 and S1-N300 also significantly increased the antioxidant enzyme activity in maize root system, mitigating reactive oxygen species accumulation, and increasing K+, Ca2+, and Mg2+ content compared with other treatments, as well as promoting root growth and development. Moreover, under S1, the levels of Indole-3-acetic acid (IAA), Gibberellins (GAs), and Zeatin + zeatin riboside (Z+ZR) content were 45, 43, and 30％ higher, respectively, compared with S3. Simultaneously, promoted biomass accumulation (ear: 28.4; leaf: 34.3; stem: 22.5; grain: 22.5), maize yield (16.3％). The different patterns of water-N interaction are explained by 94, 89, 94, and 91% of the variations in maize yield, Ion, endogenous hormone and ROS, respectively. Therefore, the interaction of water and N in S1-N300 regulated the distribution of the root system, which improved the capability of maize root’s adversity resistance and nutrient uptake, and eventually increased maize growth and yield.

Keywords: Maize, enzymes, Crop yield, Nitrogen, root development, Water stress