Sorption of Some14C-Herbicides by Isolated Plant Cells and Protoplasts

Abstract

Isolated plant cells (Zinnia elegansJacq. leaf tissue) and protoplasts (immature tomato fruit,Lycopersicon esculentumMill.) were obtained by hydrolysis of pectic substances in the middle lamella and the primary cell wall, respectively. Both types of cells were stabilized in an inorganic salt solution and used to study absorption and distribution of four14C-herbicides. Intracellular distribution within the protoplast was determined by ultracentrifugation in a discontinuous Ficoll gradient. Marked absorption ofp-nitrophenyl-α,α,α-trifluoro-2-nitro-p-tolyl ether (fluorodifen) and α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) by the isolated cells was observed; absorption increased with time. Trifluralin was retained within the cell more strongly than fluorodifen. Similar absorption patterns of fluorodifen and trifluralin by protoplasts were observed. Trifluralin was incorporated to a greater extent than fluorodifen by the cells and protoplasts. Trifluralin was distributed evenly between the mitochondrial and the chloroplasts-nuclei fractions; whereas fluorodifen was concentrated in the chloroplast-nuclei fraction. No significant absorption of 1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea fluometuron) or 3-(4-bromo-3-chlorophenyl)-1-methoxy-1-methylurea (chlorbromuron) was detected by either the isolated cells or protoplasts.