Uptake of Herbicides by Soybean Roots in Culture Solutions

Abstract

Uptake of herbicides by excised roots of soybean(Glycine max(L.) Merr.) plants was studied over periods of 30 min, 8 hr, and 48 hr. In the 48-hr experiment, initial rate of herbicide uptake was rapid and was greater at higher temperatures and external herbicide concentrations. Rates of initial uptake varied among herbicides. Over 30-min periods, rapid herbicide uptake by excised roots for 2.5 to 5 min was followed by much slower uptake. Total uptake for 30 min and 1 hr was in the order of 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea(linuron) > isopropyl-m-chlorocarbanilate (chlorpropham) >S-ethyl dipropylthiocarbamate (EPTC) > 3-amino-2,5-dichlorobenzoic acid (amiben) > 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine (atrazine). However, total uptake after 48 hr was in the order of chloropropham > linuron > EPTC > atrazine > amiben, indicating that rates of uptake for the herbicides changed over 48 hr. Values of Q10for herbicide uptake were always less than 1.85, indicating that physical processes were important in uptake of herbicides by excised soybean roots. Uptake of herbicides over 8 hr by roots of intact plants was similar at 5, 10, and 20 C to uptake by excised roots, but uptake at 30 C was less for roots of intact plants than for excised roots. Transpiration increased as temperature increased, but herbicide uptake and transpiration were unrelated.

Physiological Basis for Triazine Herbicide Tolerance in Bermudagrass, Seashore Paspalum, and Zoysiagrass

“…This harvest timing was chosen based on previous research with root-applied 14 C-atrazine and 14 C-simazine in corn, sorghum, and soybean (Moody et al, 1970;Shimabukuro, 1968). This harvest timing was chosen based on previous research with root-applied 14 C-atrazine and 14 C-simazine in corn, sorghum, and soybean (Moody et al, 1970;Shimabukuro, 1968).…”

“…), sorghum, and soybean (Moody et al, 1970;Shimabukuro, 1968;Thompson, 1972). Tubes were wrapped in aluminum foil, and cotton balls were placed at the base of plants to allow root submergence in solution.…”

Uptake of chlorobenzenes by tissues of the soybean plant: Equilibria and kinetics

“…Chem. 15,1996 D.D. Tam et al were obtained from Aldrich Chemical Co.; hexachlorobenzene (HCB) was obtained from BDH.…”

“…no relation to uptake times in a viable plant in which rates are determined by diffusion and flow rates within the plant. The tissues were frozen to avoid any complications from active transport, transpiration, photosynthesis, plant growth, or degradation of the chemical by the plant [14][15][16].…”

“…We believe, however, that an understanding of uptake under simple artificial conditions is a prerequisite to understanding uptake under real, complex conditions. The soybean, Glycine max L., was used because it is of considerable economic value and has been extensively studied by Casterline et al [17], Fletcher and Johnson [18], Fletcher et al [19], McFarlane et al [20], Moody et al [15], Nash and Beall [21], and Suzuki et al [22]. Four parts of the plant were treated, namely leaves, petioles, stems, and roots.…”