| Effects of nitrogen on root characteristics and yield formation in drought\|stressed maize during the flowering stage |
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| DOI：10.7606/j.issn.1000-7601.2025.01.15 |
| Key Words: nitrogen drought stress maize root characteristics yield |
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| Abstract: |
| Two maize cultivars with differing drought sensitivities—drought\|resistant ‘Zhengdan 958’ and drought\|sensitive ‘Xianyu 335’—were grown in soil columns under varying water treatments (normal irrigation and drought stress) and nitrogen levels (0 and 7.2 g·plant-1). The objective was to investigate the effects of these factors on root morphology, physiology, aboveground growth, and grain yield under drought stress during the flowering stage. The results showed that drought stress at the flowering stage inhibited the occurrence and growth of brace roots and shallow crown roots, leading to a decrease in total root length, total root surface area, and total root volume by 1.30%～38.73%, 4.95%～42.42%, and 17.69%～51.58%, respectively. N application promoted the growth of brace roots and shallow crown roots, alleviating the adverse effects of drought stress on root growth. Regarding the root physiological activity, drought reduced the proportion of active absorption area by 5.56%～18.46%, while N application increased the proportion of active absorption area and root activity under drought by 7.54%～11.65% and 40.79%～44.84%, respectively. The response of maize aboveground growth to drought and N was generally consistent with that of the root system. Drought stress significantly reduced leaf SPAD, leaf area, and plant biomass, while N applications increased leaf SPAD, leaf area and plant biomass by 28.57%~31.25%, 14.60%~35.76% and 14.72%~42.63%, respectively. The drought resistance index of N-treated plants was 1.59～3.52 times higher than that of plants without N application. Drought stress during the flowering stage resulted in a 12.97% to 30.69% reduction in the grain numbers per spike at harvest, whereas nitrogen deficiency primarily impacted the 100-grain weight, leading to a decrease of 7.48% to 38.94%. N application promoted grain yield of maize under drought stress at the flowering stage by 19.82%～166.47%. ‘Xianyu 335’ was more sensitive to drought stress and N regulation than ‘Zhengdan 958’. In conclusion, the application of nitrogen enhanced root growth and physiological activity in maize under drought stress during the flowering stage, improving soil water and nutrient absorption. It also promoted aboveground biomass production and grain yield formation, significantly boosting maize’s drought resistance. |
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