Influence of foliar application of maize grains extract (aqueous and alcoholic) on the nutrient acquisition, osmoprotectants accumulation, ROS-scavenging system, and endogenous phytohormones profile in salt-stressed plants has received no attention. Therefore, the current study, as a first report, was aimed to test the hypothesis that the maize grains extract (MGE) application may give an advantage to overcome salinity problems by altering these mechanisms. Phaseolus vulgaris L., cv. Paulista plants were grown in salty soils (EC = 7.43–7.51 dS m^‒1) with and without MGE applications as follows: both seeds and plants were treated by distilled water (MGE0), seeds soaked in MGE and plants sprayed with distilled water (MGEseeds), seeds soaked in distilled water and plants sprayed with MGE (MGEplants), as well as both seeds and plants were treated by MGE (MGEboth). MGE treatments protected plants against the deleterious effects of saline condition by improving growth and yield components, relative water content, membrane stability index, photosynthetic pigments content, soluble sugars, proline, N, P, K⁺, Ca²⁺, indole-3-acetic acid, gibberellic acid, cytokinins concentrations, K⁺/Na⁺ and Ca²⁺/Na⁺ ratios, superoxide dismutase, catalase, peroxidase activities, and glutathione, ascorbate contents. Therefore, MGE as environmental-friendly, sustainable and efficient strategy can reprogramme plant responses to mitigate the adverse effects of salinity stress.

Salicylic acid (SA) and melatonin (MT) have been shown to play important roles in plant salt tolerance. However, the underlying mechanisms of SA–MT-interaction-mediated ionic homeostasis in salt-stressed plants are unknown. As a first investigation, this study aimed to clarify how SA–MT interaction affects H⁺-pump activity in maintaining the desired ion homeostasis under saline conditions and its relation to ROS metabolism. Wheat (Triticum aestivum L.) plants were grown under non-saline or saline conditions and were foliar sprayed with 75 mg L⁻¹ SA or 70 μM MT. The SA+MT combined treatment significantly increased N, P, K⁺, Fe, Zn, and Cu acquisition, accompanied by significantly lower Na⁺ accumulation in salt-stressed plants compared to non-stressed ones. Additionally, it significantly enhanced ATP content and H⁺-pump activity of the roots. The mitigation was also detected in the reduced superoxide radical content, electrolyte leakage, and lipoxygenase activity, as well as increased superoxide dismutase, catalase, peroxidase, and polyphenol oxidase activities; K⁺/Na⁺, Ca²⁺/Na⁺, and Mg²⁺/Na⁺ ratios; relative water content; membrane stability index; and free amino acid accumulation in treated plants. The novel evidence shows that the higher root H⁺-pump activity in treated plants is a tolerance mechanism that increases the salt tolerance via maintaining ionic homeostasis.