Effect of Soil Water Stress and Soil Temperature on Translocation of Diuron

Abstract

Rates of photosynthesis, respiration, and transpiration of wheat (Triticum aestivum L., var. Gaines) were determined as functions of time, under controlled conditions of moderate soil water stress and soil temperature, after treatment of the roots with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron). Air temperature, relative humidity, light intensity, and air movement were maintained constant. The rate of photosynthesis declined with time for all plants treated with diuron but not for the controls. No change in the rate of respiration was detected. The rate of transpiration decreased slightly immediately upon application of the diuron and then remained constant. The data indicate that soil temperature and soil water stress play important roles in the herbicidal action of diuron applied to the soil.