Avaliação do potencial da inoculação combinada de fungos e bactérias na atenuação dos danos desencadeados pela seca em plantas de soja

Abstract

Soybeans are among one of the most economically important legumes that provide food for humans and animals, however, its yield is low due to periods of drought that reduce their productivity. Drought is a big problem that occurs worldwide, where the unavailability of water in the soil affects plant development. One of the first reactions to water scarcity is the decrease in transpiration rates, through stomatal closure, which consequently decreases stomatal conductance (gs), which reduces photosynthetic rates. These physiological dysfunctions impact negative effects on crop yield, with frequent loss of productivity. In this way, it is extremely important to seek ecological alternative methods in order to mitigate the damages triggered by water scarcity. In this project, we evaluated the combined inoculation of different plant growth promoting microorganisms (MPCV), as they have ability to mitigate the harmful effects caused by drought stress, increasing the productivity and biosynthesizing essential nutrients for plant development. Therefore, among several MPCV, we used strains of Bacillus subtilis bacteria (BV02 and BV09) and the fungus Trichoderma asperellum (BV10), where we prepared a syrup and homogenized the soybean seeds that were planted in properly fertilized soil, with treatments: control (CT), water deficit (DH), DH + BV02+BV10 and DH + BV09 + BV10. the soybean plants were submitted to these treatments for 10 days and after this period, the following were evaluated: water relationship, the content of chloroplast pigments and gas exchange. from the results obtained, we observed that the plants treated with the microorganisms showed higher water potential, therefore, a greater degree of hydration, a greater content of chloroplast pigments, and showed higher photosynthetic rate compared to plants under HD, therefore, greater assimilation of CO2, higher gs, higher ratio (Ci/Ca), higher transpiration rate (E) and higher efficiency of the water use (USA). We can conclude that these microorganisms have great potential to be used in sustainable agricultural programs.