Kinetics of phosphorus uptake in transgenic soybeans after glyphosate application

Abstract

There are indications that glyphosate could affect the phosphorus nutrition of soybean. Thus the present study was to evaluate P uptake absorption and allocation in soybean after glyphosate application. Two experiments were conducted in green-house in randomized complete block. The 1^st experiment evaluated the glyphosate at 0,0; 1,5; 3,0; 6,0 and 12,0 g ha^-1 and the 2^nd experiment evaluated the glyphosate at 0,0; 200; 400 and 800 g ha^-1. Glyphosate was applied at 21 days after plant emergence in foliar soybean variety 'Valiosa RR'. Then the plants were grown in nutrient solution using the technique of exhaustion of the solution. After the exhaustion test, the plants were collected for determination of dry matter and P contents in shoots and roots. Although it was not possible to determine the kinetics of absorption, was not observed stimulatory effect of P uptake in soybean after applied at low rates or depressant effect when applied at compatible rates with those recommended for weed control.