Herbicide Uptake as Influenced by Plant Water Status

The effect of defined plant water status (relative water content) on the foliar influx of [14C]2,4-D [(2,4-dichlorophenoxy)acetic acid] was studied in soybean (Glycine maxL.). A positive correlation between relative water content and leaf water potential was established with a regression coefficientr= 0.978. The foliar influx of 4.45 × 10−4μmol 2,4-D cm−2hr−1was greatly decreased under plant water stress conditions. An approximately 40% decrease in 2,4-D influx was obtained when the relative water content decreased from −0.55 to −1.21 MPa.