Role of temperature and water potential on the activity of some acetanilide herbicides on threePhaseolustaxa

The effect of three acetanilide herbicides on the hypocotyl-epicotyl growth rate of three Phaseolus taxa was studied at two temperatures and two water potentials. The study proved that, apart from the detrimental effects of the herbicides, low temperature and water availability could also affect the hypocotyl-epicotyl growth rate adversely. In fact, temperature and water potential treatments had a highly significant effect throughout, and in one of the trials these two factors together caused growth reductions of 62, 66 and 71 % in Kamberg, Bonus and kidney beans, respectively. By contrast, the reductions caused by the herbicides only amounted to 5% for Kamberg, 3% for Bonus and 3% for kidney beans. It is clear that in practice very complex interactions between climatic factors and these herbicides can be expected.