Phyto and cytoxicity effects of a nicosulfuron-based herbicide in two different plant models: <i>Zea mays</i> L. and <i>Lactuca sativa</i> L

Corn is the second most cultivated crop in Brazil, nicosulfuron is widely applied in maize fields to control post-emergent weeds. Traces of nicosulfuron can be found in soil and superficial water highlighting the herbicide potential toxicity. The present work aimed to evaluate the effects of a nicosulfuron based-herbicide through bioassays with the plant model <i>Lactuca sativa</i> L. (lettuce) and the crop plant <i>Zea mays</i> L (maize). The test solutions were prepared from commercial products and contained nicosulfuron at the following concentrations: 0.3; 0.6; 1.3; 2.3; 5.0; 10.0; 15.0; 20.0; 25.0 e 30.0 mg L^-1. Distilled water was used as a negative control, and aluminum solution was used as a positive control. Macroscopic analyses were performed for both models, and microscopic analysis were performed only for <i>L. sativa</i>. The negative interference of the nicosulfuron-based herbicide on lettuce was observed for all macroscopic parameters analyzed reducing germination, germination speed, root and shoot growth even at the dosage of use recommended for field application by the herbicide manufacturer, 5 mg L^-1. For the microscopic parameters the frequency of chromosome alterations and condensed nuclei were not significant but micronuclei were significantly increased. The data demonstrate that the herbicide based on nicosulfuron is potentially hazardous.