Dinoseb (2-sec-butyl-4,6-dinitrophenol) and MBR 8251 [1,1 1-trifluoro-4′-(phenylsulfonyl)-methanesulfono-o-toluidide] inhibited enzymic synthesis of glycerides in vitro. The physiological significance of this inhibition was confirmed in intact wheat [Triticum aestivum L., ‘Mediterranean’ (C.I. 5303)] seedlings; dinoseb and MBR 8251 inhibition of glyceride synthesis in vivo was evidenced by a buildup in free fatty acids and a decrease in neutral and polar lipids. Glyceride synthesis and growth were reduced approximately equally by dinoseb and MBR 8251. However, polar (membrane) lipids were reduced more drastically than growth. It is suggested that dinoseb and MBR 8251 alter membrane structure and function through an inhibition of membrane lipid synthesis. DNP (dinitrophenol) was only slightly inhibitory in either the in vitro or in vivo system. Dinoseb was more effective than MBR 8251 in destruction of cell membrane permeability of intact roots immediately after treatment.

Diffusion of trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) through Mexico silt loam soil was measured in diffusion cells under laboratory conditions. Radiolabeled herbicide was extracted from each sample and counted by liquid scintillation. Fick's Second Law with a constant diffusion coefficient adequately describes trifluralin diffusion regardless of concentration or diffusing time. Solution diffusion increases directly with bulk densities to 1.1 g/cm3 and then decreases. Vapor diffusion is decreased approximately 50% for every 10% decrease in air-filled porosity. Vapor diffusion contributes the major portion of total diffusion at bulk densities of less than 1.2 g/cm3. For bulk densities between 1.2 and 1.4 g/cm3, the magnitudes of vapor and solution diffusion are similar.

In the range of 4.4 to 49 C, there is an exponential relationship between temperature and trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine) diffusion coefficients. Diffusion is low in air-dry soil for all temperatures. It increases to a maximum value when the soil has between 8 and 15% w/w soil moisture content and then decreases steadily as moisture content increases. When the air-filled fraction of soil void space is reduced below approximately 40% v/v by either compression or addition of moisture, diffusion begins to decrease. An equation was developed to predict trifluralin diffusion coefficients from a factorial experiment with seven soil moisture contents, five soil temperatures, and two bulk densities. Diffusion coefficients range from 3.8 X 10-11 cm2/sec to 2.8 X 10-6 cm2/sec. Fifteen terms are required in the prediction model to describe accurately the response surface of trifluralin diffusion coefficients. With the equation it is possible to predict trifluralin diffusion coefficients for any combination of measured soil parameters as long as they are represented by the range of the variables used in the experiment.