Possible toxicity and tolerance patterns towards post-emergence herbicides in maize inbred lines

Abstract

High weed infestation of seed crops often makes various measures that should be performed at the optimum time difficult, hence post-emergence herbicides have become the usual way of weed control in maize seed crops. The introduction of sulfonylurea herbicides has resulted in a higher susceptibility in maize inbreds. The aim of this study was to examine the effects of six post-emergence herbicides, including sulfonylurea herbicides, on the contents of fresh matter, soluble proteins, free thiolic groups and total phenolics in one-month-old plants, as well as on the grain yield of 15 commercial ZP maize inbred lines. The obtained results show that inbred plants have a whole range of responses to herbicide application. The changes in content of phenolics did not vary over a broad range among the applied herbicides; they followed mainly the level observed in control plants. However, greater variations between the results were obtained for the content of free thiolics, which are defenders against oxidative attack. The overall influence of herbicides could be considered as a decrease in the content of thiolics. Most of the applied herbicides expressed temporary stress, evidenced by a decrease in the fresh matter of the shoots, without affecting of yield at the end of vegetation. This could be connected to recovery mechanisms that include the activity of antioxidants, primarily of thiolics.