Effect of trifluralin synthesis intermediates on plant cell membrane permeability and growth of plants and fungi.

The phytotoxicity of the intermediates of (i) trifluralin synthesis, (ii) 4-chloro-α,α,α-trifluorotoluene, (iii) 4 chloro-3-nitro-α,α,α,-trifluorotoluene, and (iv) 4-chloro-3,5-dinitro-α,α,α-trifluorotoluene, in comparison with that of trifluralin, was studied. All the intermediates affected the permeability of cell membranes and inhibited corn root growth. Compound (iv) was more toxic than (iii) and (ii), and monocotyledons were more sensitive than dicotyledons. (iv) also inhibited the mycelial growth of some fungi. On the contrary, trifluralin (i) did not affect membrane function. It is suggested that the mechanism of action of (ii), (iii), and (iv) is different to that postulated for trifluralin.