THE EFFECT OF CHLORSULFURON AND DICLOFOP-METHYL ON THE UPTAKE AND UTILIZATION OF ZINC BY WHEAT

The effects of the herbicides Hoegrass and Glean on the uptake of zinc by wheat were examined in two glasshouse experiments. Application of the active ingredients chlorsulfuron and diclofop-methyl decreased shoot weight, root weight and zinc uptake similarly to the herbicides Glean and Hoegrass. It can therefore be concluded that the effects of Hoegrass and Glean on zinc uptake in wheat can be attributed to these active ingredients and not to other constituents of the commercial herbicide preparations. Effects of chlorsulfuron on zinc uptake in soil were different from those obtained in solution. In soil, chlorsulfuron decreased both zinc concentrations in the youngest emerged blade and zinc content of shoots, while in solution where uptake is not likely to be limited by the rate of zinc diffusion to sites of absorption, there were no significant effects on zinc uptake. However, in both soil and solution, shoot and root weights were decreased by herbicide, particularly at low rates of zinc supply. Roots were shorter and thicker when herbicide concentrations in solution were increased.