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Acta Prataculturae Sinica ›› 2024, Vol. 33 ›› Issue (11): 135-148.DOI: 10.11686/cyxb2023477

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Abiotic stress priming affects the responses of maize (Zea mays) plants to cadmium stress

Xiao-xiao LI(), Pan ZHANG, Yuan LU, Ting LI, Na ZHAO, Jia-wen WU()   

  1. College of Life Sciences,Yan’an University,Yan’an 716000,China
  • Received:2023-12-13 Revised:2024-01-31 Online:2024-11-20 Published:2024-09-09
  • Contact: Jia-wen WU

Abstract:

Cadmium (Cd) pollution in arable land in China is becoming an increasingly serious problem. The aim of this study was to elucidate how various abiotic stresses prime the responses of maize (Zea mays) to Cd stress. On the one hand, abiotic stress priming that reduces Cd accumulation can be used to safeguard the quality of maize for consumption; on the other hand, abiotic stress priming that increases Cd accumulation in maize can be used to enhance phytoremediation efficiency when maize plants are grown in Cd-polluted soil. Maize seedlings were subjected to priming treatments for a short time. Drought, salt, and iron deficiency were used as cross-stress priming treatments, and a low dose of Cd was used as the same stress priming treatment. After the various stress treatments, the maize seedlings were subjected to Cd stress, and then their biomass, root morphology, tolerance index, Cd concentration, Cd accumulation, subcellular Cd distribution, and antioxidant defense capacity were determined. The application of iron deficiency, salt stress, and drought as stress priming treatments resulted in a reduction in the dry weight of maize roots, stems, and leaves. However, priming with these abiotic stresses significantly enhanced the tolerance indices of maize under Cd stress. Specifically, drought stress priming led to a decrease in the Cd concentration and accumulation in the roots, stems, and leaves of maize plants. Additionally, it promoted the localization of Cd in vacuoles. By contrast, priming with a low dosage of Cd enhanced Cd concentrations in roots and leaves and Cd accumulation in leaves, but did not alter the subcellular distribution of Cd. Priming with abiotic stresses did not significantly change the activities of superoxide dismutase, peroxidase, and catalase in the leaves and roots of maize plants under Cd stress, suggesting that abiotic stress priming does not stimulate the activities of antioxidant enzymes during the response to Cd stress in maize. Correlation analyses showed that total root length was closely correlated with Cd accumulation in maize. The total root length was affected by abiotic stress priming. Moreover, the Cd concentration in the leaf cell walls was positively correlated with Cd accumulation in maize. In contrast, the Cd concentration in vacuoles of root cells was negatively correlated with Cd accumulation in maize. Our results show that abiotic stress priming can significantly promote the Cd tolerance of maize, and that drought priming can decrease Cd accumulation in maize.

Key words: Cd accumulation, priming, abiotic stress, maize, antioxidant