Alleviation effect of gibberellin A3 on antagonism of manganese to glyphosate

MnSO4, applied as a foliar fertilizer in tank mixtures with glyphosate, may antagonize the control efficacy of glyphosate. So it is very important to find out a way to relieve or eliminate the antagonistic effect of manganese to glyphosate. The purpose of present study is to investigated the relieving effect of gibberellin A3(GA3) on antagonism of manganese to glyphosate in Festuca elata by spraying mixture of glyphosate and manganese and GA3. The results indicated that spraying GA3 in tank mixtures with glyphosate and manganese could make the leaf color of Festuca elata more yellow and increase the leaf wilting to some extent when compared with that spraying the mixture of glyphosate and manganese; and the toxic symptom of Festuca elata is similar with that spraying glyphosate alone; GA3 at 50 mg/L showed the best relieving effect.After foliar spray of GA3 in tank mixtures with glyphosate and manganese, the fresh weight,plant height and chlorophyll content of Festuca elata decreased greatly while shikimate acid content and MDA accumulation in leaves increased significantly.In comparison with glyphosate and Mn2+ mixture treated plants, the content of leaf shikimate acid saw an obvious climbing trend in GA3-contained groups, which raised 49.8% (50 mg/L GA3) and 28.8% (30 mg/L GA3) on the 6th day after spraying. In addition, contents of MDA in plants also significantly increased (54.1%, 50 mg/L GA3 and 52.9%, 30 mg/L GA3) after 2th day of GA3-contained spray treatments.The results suggested that foliar spray of GA3 in tank mixtures with manganese fertilizer and glyphosate will largely alleviate the antagonism of manganese to glyphosate and ensure the control efficacy of glyphosate to weeds.