Oxidative Stress Produced by Paraquat Reduces Nitrogen Fixation in Soybean-Bradyrhizobium diazoefficiens Symbiosis by Decreasing Nodule Functionality

Soybean (Glycine max.) is one of the most important legumes cultivated worldwide. Its productivity can be altered by some biotic and abiotic stresses like global warming, soil metal pollution or over-application herbicides paraquat (1,1’-dimethyl-4,4’-bipyridinium dichloride). In this study, effect oxidative stress produced addition (0, 20, 50 100 µM) during plant growth on symbiotic nitrogen fixation (SNF) functionality Bradyrhizobium diazoefficiens-elicited soybean nodules were evaluated. Results showed that µM was threshold B. diazoefficiens tolerate under free-living conditions. symbiosis with soybean, statistically reduced shoot root dry weight plants, number development nodules. SNF negatively affected paraquat, which total content fixed close to 50% when added. These effects due impairment nodule increased status nodules, as revealed lower leghaemoglobin higher lipid peroxidation in from paraquat-treated plants.