Soil Acidity Conditioning the Productivity and Physiology of Wheat Inoculated with Azospirillum brasilense

Abstract

ABSTRACT The increase in the world population creates the need for sustainable food production and the use of synthetic fertilizers with growth-promoting bacteria. The objective of this research was to evaluate the acidity on the physiological and productive variables of wheat inoculated with Azospirillum brasilense and treated with osmoprotective additives. Combinations of A. brasilense, osmoprotectant and chemical treatment were evaluated in wheat seeds planted in contrasting acidity soil (pHs: 4.8 and 6.5). Evaluations of the physiological parameters were carried out in the foliar tissue (hydrogen peroxide content, superoxide dismutase activity, lipid peroxidation, content of chlorophyll a, b, and total and carotenoid and nitrate reductase enzyme activity) during the vegetative period and flowering. The grain yield components were evaluated after the physiological maturation. Plants grown in uncorrected soil acidity (pH: 4.8) showed higher lipid peroxidation. The other plants (pH: 6.5) have higher levels of nitrate reductase. Higher nitrate reductase activity was also observed in plants inoculated with A. brasilense. Therefore, in soil acidity 6.5, both A. brasilense isolate or combined with osmoprotective additive increased the grain yield. Nevertheless, the osmoprotectant application did not attenuate the effects of the chemical treatment of seeds and exerted a negative effect to inoculation with A. brasilense.