Causes and consequences of woody plant encroachment into western North American grasslands.

As woody plants encroach into grasslands, grass biomass, density and cover decline as wood plant biomass, density and cover increase. There is also a shift in location of the biomass from mostly belowground in the grasslands to aboveground in the woodlands. In addition, species richness and diversity change as herbaceous species are replaced by woody species.

Effectiveness of phosphate acquisition by juvenile cold-desert perennials from different patterns of fertile-soil microsites.

Phosphate uptake was measured for Artemisia tridentata, Agropyron desertorum and Pseudoroegneria spicata, three common perennial North American Great Basin species. Four patterns of nutrient-rich microsites were used in the experiments (different distances, densities and nutrient concentrations) All species were more efficient at taking up P from microsites nearest the plants than from more distant microsites. Artemisia and Agropyron acquired P more rapidly from the distant microsites when there was a larger number of microsites and, therefore, a greater probability of encounter.

Translocation, distribution, and environmental degradation of hexachlorophene in tomatoes.

The translocation, distribution, metabolism and environmental degradation of hexachlorophene were investigated in tomato plants (Lycopersicon esculentum Mill cv. beefsteak). All plants were grown under standardized conditions and treated with leaf-applied 14C-ring-labeled hexachlorophene (HCP).

Extraction and gas-liquid chromatographic determination of hexachlorophene from several plant tissues.

Conditions are described for extraction, cleanup, derivatization, detection, and quantitation of hexachlorophene (HCP) residues from several types of plant material. Wet plant tissue was homogenized and extracted with ethyl ether, dried, and methylated with excess diazomethane. Samples were precleaned by column chromatography on silica gel with benzene-petroleum ether (1 + 1), and then 1-10 microliter concentrated sample was chromatographed on a 6' column of 3% SE-30 on 80-100 mesh Gas-Chrom Q.