Efeitos dos fungos micorrízicos arbusculares sobre os parâmetros fisiológicos e de crescimento do milho sob déficit hídrico.

Abstract

the most significant for maize production, as it can cause physiological and growth changes in the plant. One strategy to mitigate the negative effects of WD is the use of arbuscular mycorrhizal fungi (AMF), which provide greater acclimation capacity to WD conditions by enabling increased water and nutrient absorption, such as phosphorus and nitrogen. The aim of this study was to evaluate the responses of chlorophyll a fluorescence characteristics and growth in maize plants subjected to water deficit and inoculated with arbuscular mycorrhizal fungi (AMF). The experiment was conducted in a greenhouse at the Postgraduate Program in Agroecology of the State University of Maranhão, located in São Luís/MA, from September to November 2023. The soil used was collected from a preserved vegetation area at the University's School Farm. Hybrid maize seeds AG1051, with an early cycle, were used. For soil inoculation in the AMF treatments, the species identified as Rhizoglomus clarum, acquired from the Embrapa Agrobiologia germplasm bank (Seropédica, RJ), was used. The experimental design was in randomized blocks, with a factorial scheme of 4 (sterile soil; natural soil; sterile soil + R. clarum; natural soil + R. clarum) x 2 (irrigated and water deficit), and four replications, totaling 32 experimental plots. Each plot was represented by a 20 L capacity pot, with one plant per pot. The experiment lasted for 51 days, until the V5-V6 stage. Meteorological variables were monitored throughout the day, and soil moisture was maintained at 90% of field capacity (FC) until 46 days after planting, when water restriction occurred, and stressed treatments were maintained at 20% of FC. According to the results, water deficit significantly reduced plant height, stem diameter, leaf area, specific leaf mass, fresh leaf and stem mass, as well as dry leaf, stem, and root mass. Therefore, inoculation with Rhizoglomus clarum in natural soil mitigated some of these negative effects, resulting in higher growth values compared to sterile soil under water stress. Under irrigated conditions, inoculation with R. clarum and natural soil had higher biomass compared to the sterile treatment. Inoculation with AMF had a significant impact on chlorophyll a fluorescence. Additionally, higher levels of carotenoids were observed, both under water deficit and irrigated conditions, compared to the sterile treatment. These results indicate that the application of AMF had a synergistic effect on maize plants, influencing physiological and biochemical processes.