The Involvement of Antioxidant Enzyme System, Nitrogen Metabolism and Osmoregulatory Substances in Alleviating Salt Stress in Inbred Maize Lines and Hormone Regulation Mechanisms

Abstract

Salt stress inhibited the growth of maize. B46 and NC236 were chosen as materials and NaCl concentrations (0, 55, 110, 165, and 220 mmol L−1) were set. We found the activities of SOD, POD, CAT, APX, GR, MDHAR, and DHAR decreased under NaCl stress. Compared with NC236, the contents of AsA and GSH, AsA/DHA and GSH/GSSG of B46 decreased. The content of O2−, H2O2, MDA, and EL of B46 increased. The contents of NO3− and NO2− decreased, while the content of NH4+ increased under high NaCl concentration. The activities of NR and NiR decreased, while the activities of GS and GOGAT increased first and then decreased. For B46 and NC236, the maximum of NADH-GDH and NAD-GDH appeared at 165 and 110 mmol L−1 NaCl concentration, respectively. Compared with B46, and the GOT and GPT activities of NC236 increased first and then decreased. With the increase of NaCl concentration, the contents of proline, soluble protein, and soluble sugar were increased. The Na+ content of B46 and NC236 increased, and the K+ content and K+/Na+ decreased. Compared with NC236, B46 had higher IAA content in leaf, higher Z + ZR content in leaf and root, and lower ABA content in leaf and root.

Research Progress on the Mechanism of Salt Tolerance in Maize: A Classic Field That Needs New Efforts

“…Simultaneously, it led to a decrease in lipid peroxidation and stomatal conductance [ 27 ]. In line with this, under NaCl stress, Wang et al (2022) found that the activities of SOD, POD, CAT, APX, GR, MDHAR, and DHAR decreased, with increased content of ROS level, proline, soluble protein, soluble sugar, and MDA [ 28 ]. Jiang et al (2017) showed selenium (Se) application increased the SOD and APX activities and the expression level of ZmMPK5, ZmMPK7, and ZmCPK11 under salt stress, with an enhanced net photosynthetic rate [ 29 ].…”

The Impact of Shale Oil Residue on the Growth and Physiological Characteristics of Corn Seedlings under Saline Soil Conditions

“…In such conditions, plants tend to undergo an increase in osmoprotectants, such as proline, to reduce cell water potential and enhance the absorption capacity of soil moisture [35]. Previous studies have indicated that salt stress increases the proline content in maize seedlings [9,[36][37][38]. However, the addition of the three types of oil shale waste residues seems to alleviate salt stress, subsequently reducing the proline content in maize seedlings.…”

“…Excessive ROS damages cell membranes, increases electrolyte leakage, and reduces membrane stability, leading to the accumulation of membrane lipid peroxidation products, such as malondialdehyde (malondialdehyde) [10,11,36,37,41]. Previous studies have reported an increase in malondialdehyde content in maize seedlings under salt stress [9,37,38]. One study, for instance, indicated that when the salt (NaCl) concentration was 100 mM, the malondialdehyde content in maize seedlings increased by 310.9% compared to the control [42].…”

“…However, all three types of oil shale waste residue treatments reduced malondialdehyde content compared to the control, suggesting the potential alleviation of oxidative damage to cell membranes. The enzymatic antioxidant system in plants, including superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), plays a crucial role in mitigating stress-induced ROS accumulation [10,11,28,29,38,43]. Superoxide dismutase (SOD) acts as the "first line of defense" in plants against oxidative damage by converting superoxide radicals into H 2 O 2 and molecular oxygen, which are then transformed into water by POD and CAT [43].…”

Redox control of metabolism in wheat

“…It can cause a cascade of phenological, physiological, genetic, biochemical, metabolic, and molecular changes that have a deleterious impact on plant growth and development (Fig. 3) [134][135][136][137]. Extreme (low or high) temperatures and light stress (intensity and spectrum) are often linked and may induce similar modifications in the redox system of plants.…”