Water deficit inhibits plant growth by affecting several physiological processes, which leads to the overproduction of reactive oxygen species (ROS) that may cause oxidative stress. In this regard, iodine (I) is already known to possibly enhance the antioxidant defense system of plants and promote photosynthetic improvements under adverse conditions. However, its direct effect on water deficit responses has not yet been demonstrated. To verify the efficiency of I concerning plant tolerance to water deficit, we exposed soybean plants to different concentrations of potassium iodide (KI) fed to pots with a nutrient solution and subsequently submitted them to water deficit. A decline in biomass accumulation was observed in plants under water deficit, while exposure to KI (10 and 20 μmol L⁻¹) increased plant biomass by an average of 40%. Furthermore, exposure to KI concentrations of up to 20 μM improved gas exchange (~71%) and reduced lipid peroxidation. This is related to the higher enzymatic antioxidant activities found at 10 and 20 μM KI concentrations. However, when soybean plants were properly irrigated, KI concentrations greater than 10 μM promoted negative changes in photosynthetic efficiency, as well as in biomass accumulation and partition. In sum, exposure of soybean plants to 10 μM KI improved tolerance to water deficit, and up to this concentration, there is no evidence of phytotoxicity in plants grown under adequate irrigation.

A water deficit can negatively impact fruit yield and quality, affecting critical physiological processes. Strategies to mitigate water deficits are crucial to global food security. Iodine (I) may increase the efficiency of the antioxidant system of plants, but its role against water deficits is poorly understood. This study aimed to evaluate the effectiveness of I in attenuating water deficits and improving fruit quality, investigating whether metabolic responses are derived from a “priming effect” or stress relief during water deficits. Tomato plants were exposed to different concentrations of potassium iodide (KI) via a nutrient solution and subjected to a water deficit. A water deficit in tomatoes without KI reduced their yield by 98%. However, a concentration of 100 μM of KI increased the yield under a water deficit by 28%. This condition is correlated with increased antioxidant activity, photosynthetic efficiency improvement, and malondialdehyde reduction. In addition, the concentration of 100 μM of KI promoted better fruit quality through antioxidant capacity and a decline in the maturation index. Therefore, KI can be an alternative for attenuating water deficits in tomatoes, inducing positive responses during the water deficit period while at the same time improving fruit quality.

Selenium (Se) is an essential element for humans. However, much of the world’s human population is deficient in this element, which has become a public health problem. This study aimed to evaluate whether applying severe water stress to wheat plants (Triticum aestivum L.) could allow Se to reduce the production losses and increase the grain quality, thereby contributing to the reduction in hidden hunger. The experiment was conducted in a randomized block design with four replications in a 5 × 2 factorial scheme, with five doses of Se (0.00, 0.25, 0.50, 1.00, and 2.00 mg dm⁻³) and two irrigation conditions (with and without water deficit). When sodium selenate (Na₂SeO₄) was applied to the soil, the grains were rich in Se. Under low doses, there was an enrichment of the grains in sulfur, iron, copper, and zinc as well as total free amino acids and total soluble proteins, and lower losses in productivity under severe water stress. Higher doses decreased the concentration of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂), increased the catalase activity, and increased the water use efficiency (WUE). Therefore, applying Se at a dose of 0.25 mg dm⁻³ is effective for the biofortification of wheat grains. It enhances grain nutritional quality, increases Se bioaccessibility, and reduces production losses under water stress conditions.

Since selenium (Se) is an essential element for humans and beneficial for mitigating abiotic stresses in plants, and considering that rice is a global staple food that may lose nutrients during cooking, this study evaluated the effects of soil-applied Se on rice plants subjected to water deficit and its impact on the bioaccessibility of Se and other minerals in flour and cooked grains. The experiment followed a 5 × 2 factorial design with five Se doses (0, 0.2, 0.4, 0.6, and 1.0 mg kg ^-1 ) and two water regimes (irrigated and water-deficient). Physiological parameters, biomass, and yield were assessed, and a simulated human gastrointestinal system was used to determine the bioaccessibility of Se, Fe, Mn, and Zn. Selenium application and water management did not affect biomass or grain yield, but Se provided a practical advantage by maintaining physiological resilience and yield stability under water deficit. Se reduced malondialdehyde (MDA) concentrations, increased water-use efficiency (WUE) by approximately 35.30% under water deficit, and enhanced antioxidant enzyme activity, while water deficit decreased CO₂ assimilation. To achieve optimal grain Se levels while mitigating MDA and enhancing WUE under water deficit, 0.6 mg kg ^-1 was the ideal rate. Se bioaccessibility did not differ between flour and cooked grains, whereas cooking significantly reduced the bioaccessibility of iron (Fe), manganese (Mn), and zinc (Zn) by approximately 41%, 69%, and 81%, respectively. Soil Se application is an effective strategy for biofortifying rice grains and mitigating water stress. Maintaining Se bioaccessibility post-cooking highlights the potential of biofortification to reduce hidden hunger and promote food security.