Silicon and arbuscular mycorrhizal fungi improve water-use efficiency and drought tolerance in sweet corn

Abstract Maize is a crop that plays a fundamental role in global food security, particularly in tropical and subtropical regions. However, drought stress remains one of the major constraints that limit maize production worldwide. Maize sensitivity to water deficit is especially critical during the flowering stage, often resulting in substantial yield losses. This study aimed to investigate a sustainable strategy to mitigate drought stress in sweet corn through the combined application of silicon (Si) and inoculation with arbuscular mycorrhizal fungi (AMF) in non-sterilized native soil. We hypothesized that the association between Si and AMF could enhance drought tolerance by improving the physiological and agronomic performance of the plants. Our results demonstrated that the combined treatment increased mycorrhizal colonization by 50%, root volume by 53%, soil Si availability, and leaf concentrations of Si and P by 45% and 50%, respectively. Furthermore, under water-deficit conditions, the combined application promoted significant improvements in gas exchange parameters, including increases of 51% in photosynthetic rate, 29% in transpiration rate, 29% in stomatal conductance, and 33% in intercellular CO₂ concentration, as well as a 30% increase in leaf xylem water potential. In addition, water-use efficiency increased by 29%, while industrial yield and soluble solids content increased by 29% and 30%, respectively. These findings provide strong evidence for the synergistic effects of AMF and Si in enhancing drought resilience in sweet corn, highlighting a promising strategy for sustainable agricultural production under water-limited conditions. Further studies are required to evaluate the interaction between Si and AMF using different maize hybrids and AMF strains under drought conditions in natural soils.