Lewis, Benjamin , Thomasson, Kelly , Wachocki, Barbara , Sondossi, Mohammad .
Calcium oxalate crystals in leaves of Halogeton glomeratus and their possible contribution to alteration of soil chemistry.
Halogeton glomeratus is a highly invasive plant species that is toxic to livestock and therefore a great concern in arid rangelands of the western United States. Many plants produce soluble and insoluble salts of oxalate, which could account for more than half of their dry weight. It has been reported that the dry leaves of Halogeton glomeratus have considerable amounts of both the soluble and insoluble forms of oxalate. The possible functions of oxalates in plants has been reviewed by many. In this study, fresh and dry leaves of H. glomeratus were collected from the Desert Experimental Range in western Utah and prepared for microscopic examination for the presence and types of insoluble calcium oxalate (CaOx) crystals. In addition to light microscopy, Scanning Electron Microscopy was used to examine the crystal morphology of calcium oxalate in the leaves. Extensive presence of druse crystals was observed using both methods. Elemental analysis of these crystals confirmed their chemical composition, calcium oxalate, with some minor presence of magnesium and aluminum salts. Calcium oxalate is insoluble in water and in alkaline solutions. However it can be dissolved under acidic conditions. Considering the alkaline nature of the soils (above pH 8.0) at the study site, the dissolution of CaOx in soils would be highly unlikely without considering alternative scenarios involving soil microflora. Therefore, it is highly probable that the annual deposition of large quantities of soluble and insoluble oxalates may play a role in the mechanism of invasiveness of H. glomeratus in affected areas.
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1 - Weber State University, Microbiology, 2506 University Circle, Ogden, Utah, 84408-2506, USA
2 - Weber State University, Botany, 2504 University Circle, Ogden, Utah, 84408-2504, USA
Presentation Type: Poster:Posters for BSA Sections
Location: Event Tent/Cliff Lodge
Date: Monday, July 27th, 2009
Time: 5:30 PM