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Acta Prataculturae Sinica ›› 2026, Vol. 35 ›› Issue (1): 79-92.DOI: 10.11686/cyxb2025071

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Effects of salicylic acid on antioxidant and photosynthetic capacity of maize under high temperature, drought and their combined stress

Han-xing YANG1(), Ning-ge LIU1, Yu-lou TANG1, Huan LI1, Yi-ming ZHU1, Jia-meng GUO1,2, Hao WANG1,2, Rui-xin SHAO1,2, Yong-chao WANG1,2,3(), Qing-hua YANG1,2()   

  1. 1.College of Agronomy,Henan Agricultural University,Zhengzhou 450046,China
    2.Henan Engineering Research Center of Crop Chemical Control,Zhengzhou 450046,China
    3.Henan Key Laboratory of Regulating and Controlling Crop Growth and Development Ministry,Zhengzhou 450046,China
  • Received:2025-03-05 Revised:2025-04-29 Online:2026-01-20 Published:2025-11-13
  • Contact: Yong-chao WANG,Qing-hua YANG

Abstract:

The aim of this work was to investigate the regulatory impact of salicylic acid (SA) on the antioxidant system and photosynthetic capacity of maize (Zea mays) seedlings under high temperature, drought, and the combination of these stresses. Seedlings of the maize cultivar ‘Xianyu 335’ at the third-leaf stage were treated with a 2.5 mmol·L-1 SA solution applied as a foliar spray. High temperature and drought stress conditions were imposed using an artificial climate chamber and polyethyleneglycol-6000, respectively. The results indicate that: 1) SA augmented the activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), under heat stress and drought stress, and reduced the accumulation of malondialdehyde (MDA) and superoxide anions (O2·-). Under combined heat and drought stress, the positive correlations among antioxidant enzymes were enhanced in the SA treatment. Specifically, the correlation coefficients between SOD and POD activity, SOD and CAT activity, and CAT and POD activity were 0.93, 0.93, and 0.99, respectively. 2) SA treatment elevated the levels of soluble sugars and soluble proteins in maize leaves and roots, improved cellular water retention, and increased the overall water content in maize seedlings. 3) SA treatment improved the variable fluorescence (Fv) and maximum fluorescence (Fm) while reducing initial fluorescence (F0) in maize leaves under stress, but did not significantly affect Fv/Fm. Additionally, the SA treatment increased the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and intercellular CO? concentration (Ci). On the 5th day after the stress treatment, the values of PnTr, and Gs were 28.84%, 28.43%, and 34.21% higher, respectively, in the SA treatment than in the control. 4) SA mitigated the inhibitory effects of stress on maize seedling growth, enhancing dry matter accumulation and the root-shoot ratio. The results of this study show that SA enhances the cooperation among antioxidant enzymes under compound stress conditions. Treatment with SA improves the removal of harmful substances, mitigates the stress-induced inhibition of photosynthesis, increases overall dry matter accumulation in plants, and improves the root-shoot ratio in maize seedlings.

Key words: maize, high temperature, drought, salicylic acid, antioxidant system, photosynthesis