FORAGE PLANTS AND WEEDS THAT ARE SENSITIVE TO ATMOSPHERIC CLOMAZONE RESIDUALS

Abstract

ABSTRACT The use of indicator plants can be an effective alternative in monitoring the presence of toxic molecules in the air, such as herbicides. Thus, in the goal of this study is to assess the sensitivity of forage plants and weeds to atmospheric residual concentrations of clomazone. The treatments were arranged in a 6x5 factorial scheme, with the first factor corresponding to the plant species triticale (Triticosecale rimpaui), maize (Zea mays), sorghum (Sorghum bicolor), palisade grass (Urochloa brizantha), purslane (Portulaca oleracea) and signal grass (Urochloa decumbens), and the second factor to doses of 0, 90, 180, 270 and 360 g ha-1 clomazone doses (equivalent to atmospheric concentrations of 0.0, 0.05, 0.10, 0.15 and 0, 20 mg L-1). Twelve days after emergence, the plants were allocated inside experimental rectangular chambers with a volume of 500 dm3, covered by 150 uM of transparent polyethylene film. The plants remained exclusively in the chamber atmosphere with the herbicide for a period of 96 hours. After the chambers were opened, there were the first evaluation of intoxication and chlorophyll content, as well. The evaluations were repeated on day 7 and 14 after the chamber opening. The presence of clomazone in minimal concentrations in the atmosphere affected the quality of the evaluated plants. Signal grass, palisade grass, sorghum, triticale and purslane were sensitive to atmospheric residual concentrations of clomazone and they can be used to monitor the air quality when there are wastes from this molecule.