Effects of Azospirillum brasilense applied along with herbicides on maize

Abstract

The aim of this work was a study of a native strain (Az39) and a reference strain (Sp7) of Azospirillum brasilense, evaluating their effects on commercial herbicides like glyphosate and atrazine applied in maize. In vitro assays were performed to determine the survival capacity of both strains by adding each herbicide with and without the addition of carbon or nitrogen. A growth chamber experiment was carried out with maize plants, and the treatments consisted on applications of atrazine and glyphosate, with and without foliar inoculations of each strain. Morpho-physiological variables were determined in V6. The in vitro assays determined that the survival capacity of both strains was different in the presence of herbicides; Az39 was the only one able to survive both to the application of glyphosate and atrazine and was able to use glyphosate as the sole source of carbon. In maize plants, both herbicides affected the foliar area, the aerial and the radical biomass negatively and increased the damage of cell membranes. Most of the negative effects of both agrochemicals were mitigated with Az39, while both strains ameliorated the damage at the radical biomass. Therefore, the native strain has better adaptive characteristics against herbicides widely used in maize. This highlights the importance of the use of native microorganisms for effective inoculations in crops.