The effects of resource availability and environmental conditions on genetic rankings for carbon isotope discrimination during growth in tomato and rice

Carbon isotope discrimination (Δ) is frequently used as an index of leaf intercellular CO2 concentration (ci) and variation in photosynthetic water use efficiency. In this study, the stability of Δ was evaluated in greenhouse grown tomato and rice with respect to variable growth conditions including temperature, nutrient availability, soil flooding (in rice), irradiance, and root constriction in small soil volumes. Δ exhibited several characteristics indicative of contrasting set-point behavior among genotypes of both crops. These included generally small main environmental effects and lower observed levels of G x E interaction across the diverse treatments than observed in associated measures of relative growth rate, photosynthetic rate, biomass allocation pattern, or specific leaf area. Growth irradiance stood out among environmental parameters tested as having consistently large main affects on Δ for all genotypes screened in both crops. We suggest that this may be related to contrasting mechanisms of stomatal aperture modulation associated with the different environmental variables. For temperature and nutrient availability, feedback processes directly linked to ci and/or metabolite pools associated with ci may have played the primary role in coordinating stomatal conductance and photosynthetic capacity. In contrast, light has a direct effect on stomatal aperture in addition to feedback mediated through ci

Quantifying serum antibody in bird fanciers' hypersensitivity pneumonitis

BACKGROUND: Detecting serum antibody against inhaled antigens is an important diagnostic adjunct for hypersensitivity pneumonitis (HP). We sought to validate a quantitative fluorimetric assay testing serum from bird fanciers. METHODS: Antibody activity was assessed in bird fanciers and control subjects using various avian antigens and serological methods, and the titer was compared with symptoms of HP. RESULTS: IgG antibody against pigeon serum antigens, quantified by fluorimetry, provided a good discriminator of disease. Levels below 10 mg/L were insignificant, and increasing titers were associated with disease. The assay was unaffected by total IgG, autoantibodies and antibody to dietary hen's egg antigens. Antigens from pigeon serum seem sufficient to recognize immune sensitivity to most common pet avian species. Decreasing antibody titers confirmed antigen avoidance. CONCLUSION: Increasing antibody titer reflected the likelihood of HP, and decreasing titers confirmed antigen avoidance. Quantifying antibody was rapid and the increased sensitivity will improve the rate of false-negative reporting and obviate the need for invasive diagnostic procedures. Automated fluorimetry provides a method for the international standardization of HP serology thereby improving quality control and improving its suitability as a diagnostic adjunct

Oklahoma Agricultural Experiment Station, Bulletin no. 752, August 1980: Twenty-year results of a shortleaf pine seed source study in Oklahoma

The Oklahoma Agricultural Experiment Station periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Separating the Impacts of Crop Diversification and Rotations on Risk

It has been commonly accepted that crop rotations reduce risk compared with monoculture systems. Quantifying this phenomenon requires that effects of yield stability on risk (positive or negative) arising from rotating crops be separated from other risk elements. Using an ARS–University of Nebraska series of yields for corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] grown over a 14-yr period, both in rotation and in monoculture, the impact of crop rotation on risk was isolated and estimated. Risk was defined as the failure to meet an annual per-hectare net return target. A corn–soybean rotation had significantly less risk than monoculture practices. Diversification was found to contribute to part of this reduction while higher yields and reduced cost contributed to the remainder. This reduction in risk occurred even though the corn–soybean rotation had a higher yield variance

Fantasies of the Library

"Fantasies of the Library lets readers experience the library anew. The book imagines, and enacts, the library as both keeper of books and curator of ideas--as a platform of the future. One essay occupies the right-hand page of a two-page spread while interviews scrolls independently on the left. Bibliophilic artworks intersect both throughout the book-as-exhibition. A photo essay, “Reading Rooms Reading Machines” further interrupts the book in order to display images of libraries (old and new, real and imagined), and readers (human and machine) and features work by artists including Kader Atta, Wafaa Bilal, Mark Dion, Rodney Graham, Katie Paterson, Veronika Spierenburg, and others." -- Publisher's website