The porosity of a propylitized granite from Charroux (France), with no fractures or sealed fractures, increases by more than four times from the unaltered (0.3%) to the altered rock (1.4%). This evolution results from several local porosity modifications which occur at different scales in the rock: (1) at the core scale, from 10−1 to 10−5 m, where rock porosity changes as a function of rock-forming mineralogical composition; (2) at the mineral scale, from 10−3 to 10−7 m, where porosity depends both on the nature of the rock-forming mineral and its clay mineral alteration. Mineralogical and porosity data collected from the granite using a mineralogical map (after chemical staining and scanning electron microscopy images combined with autoradiographs) indicate that (1) the ferromagnesian rock-forming minerals — biotite and magnesiohornblende — act as the main porosity source in the unaltered granite, and (2) the nature of the clay minerals replacing rock-forming minerals in the altered granite appears to control the porosity value through two major alteration processes: chloritization and phengitization which affect the ferromagnesian minerals and produce non-porous chloritic and porous phengitic areas, respectively, at the studied scales. The observation that incipient porosity formation in granites is strongly linked to the pathway of ferromagnesian silicate alteration and subsequent clay mineral formation underlines the need to study parent-rock texture and mineralogy and their effects on subsequent near-surface weathering of granites.

Addition of a surfactant (alkylaryl polyglycol ether) increased the rate and quantity of 14C-bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] absorbed by leaves of 3-week-old hydroponically grown sunflower (Helianthus annuus L.). Autoradiographs and radioassays of plant parts indicated that the surfactant enhanced acropetal movement of bentazon in sunflower, whereas bentazon applied alone remained in the treated leaves. Basipetal movement of 14C-bentazon was insignificant in sunflower. High-pressure liquid chromatography showed that 3 days after treatment 40% of the absorbed 14C-bentazon was metabolized to a methanol-soluble metabolite. Thinlayer chromatography substantiated the occurrence of a 14C-bentazon metabolite 3 days after treatment.

Absorption and translocation characteristics of both root- and shoot-applied mefluidide N-[2,4-dimethyl-5-[[(trifluoromethyl) sulfonyl] amino] phenyl] acetamide were determined in soybean [Glycine max (L.) Merr. ‘Wells’], common cocklebur (Xanthium pensylvanicum Wallr.), and giant foxtail (Setaria faberi Herrm.). Absorption of 14C-mefluidide was greater through the foliage than the roots of all plant species. Rate of leaf absorption and translocation of 14C initially was greater in giant foxtail than in either soybean or common cocklebur, but these processes failed to increase greatly with time in giant foxtail. Absorption and translocation increased over time in soybean and common cocklebur. Soybean absorbed slightly greater quantities of 14C-mefluidide than common cocklebur, but by 8 days after labeling, common cocklebur translocated approximately 47% more radio-label out of the treated leaf than soybean. The foliar-applied 14C-label appeared to move in the phloem along with the assimilate stream in all species, mainly to areas of high metabolic activity. 14C was associated with the root systems and/or nutrient solutions of soybean and giant foxtail, but not of common cocklebur. Exuded material chromatographed as mefluidide. Movement of 14C-label in all root-treated plants appeared to be confined within the xylem with older tissue containing greater amounts of 14C than the younger tissue. Differences in selectivity between crop and weed species may be partially due to differential mefluidide absorption, translocation, and subsequent concentration in certain plant tissues.