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Eight surface soils (0–15 cm) including 1 Ferrosol, 2 Tenosols, 2 Kurosols, 1 Sodosol, 1 Chromosol, and 1 Kandosol were collected from mainly pasture sites in New South Wales. The soils had different physico-chemical properties and there were some differences between the sites in climatic conditions. Soil microbial biomass carbon (MBC) was estimated by the chloroform-fumigation extraction method, and substrate utilisation patterns determined by the Biolog method were used to assess the amount, functional diversity, substrate richness and evenness, and community structure of the microorganisms in these soils. The amount of MBC (585 µg C/g) and the microbial diversity (H´ = 3.24) were high in soils that had high clay (33%), organic C (5.96%), total N (0.45%), free iron (7.06%), moisture content (50%), and cation exchange capacitiy (133.5 mmolc/kg). These soil properties, e.g. soil moisture (r2 = 0.72), organic C (r2 = 0.58), total N (r2 = 0.63), free iron (r2 = 0.44), and EC (r2 = 0.53), were positively correlated with MBC and microbial diversity index, whereas pH and sand and silt content showed negative correlations. The climatic factors (temperature and rainfall) had no significant influence on either MBC or diversity.

The measurement and interpretation of isotherms for sorption of water onto, and oxygen permeability of, polymer substrates are important for designing polymers in applications such as agricultural seed coatings. In a preliminary study of water sorption in the commonly used copolymer poly(vinyl alcohol–co-vinyl acetate), moisture sorption isotherms were measured for a series of substrates of different comonomer composition at 25°C. The data were fitted to the D'Arcy–Watt model, which gave physically reasonable values for parameters related to the strength of monolayer adsorption to high affinity sites on the substrate and the number of sites for secondary water adsorption per unit mass. The oxygen permeability of poly(vinyl alcohol) films was found to be a function only of the water content of the films, with no other obvious contributing factors. Marked differences were seen in the populations of 'bound' and 'unbound' water characterized by 1H nuclear magnetic resonance (NMR) spectroscopy and moisture sorption isotherm fitting. There was no correlation of oxygen permeability with 'bound' or 'unbound' water measured by any means, a fact suggesting that there is a continuum of water environments within the materials.

Acetohydroxy acid reductoisomerase (EC 1.1.1.86, AHAR) was purified to a high degree from green shoots of wheat (Triticum aestivum L. cv. Vulcan). The enzyme was localised in the chloroplasts, and activity was at a maximum approximately 4 d after germination. The subunit molecular mass of wheat AHAR was 57 kD and activity of the native enzyme had an elution volume from size exclusion columns that corresponded to a molecular mass of 47 kD. The enzyme did not require the addition of Mg 2+ ions to reaction mixtures for activity. The Km values for (R,S)-2-acetolactate and (R,S)-2-aceto-2-hydroxybutyrate were 91 and 9 mM, respectively, and the corresponding maximum velocities were 430 and 451 mU mg –1 protein. The Km for NADPH was approximately 10 mM when either of the acetohydroxy acids was the other substrate. Preparation of the acetohydroxy acid substrates by hydrolysis of the parent esters in strong base led to the formation of inhibitory by-products. Racemisation of the acetohydroxy acids was detected in assay mixtures.

The distribution of the nodule-specific form of sucrose synthase (nodulin-100) in soybean nodules has been studied by immunocytochemical methods. Ultrathin sections were labelled with immunogold, and semi-thin sections with immunogold followed by staining with silver. The enzyme was located in the host cytosol, and was present to a much greater extent in uninfected inner cortical cells and interstitial cells than in infected cells. This adds further evidence that conversion of sucrose to dicarboxylic acids takes place to a greater extent in uninfected inner cortical cells and interstitial cells, than in infected cells.