Study of a Naturally Occurring Hydrilla Inhibitor.
UNIVERSITY OF SOUTH FLORIDA TAMPA CHEMICAL AND ENVIRONMENTAL MANAGEMENT CENTER
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An investigation was made of sediment from Lake Starvation northwest Hillsborough County, Florida where hydrilla, though present, has not spread during a 10-year period. The sediment was treated with water, autoclaved, and the aqueous extracts separated into molecular weight fractions by ultrafiltration. One fraction, thus obtained, inhibited the growth of hydrilla by 30 percent, as measured by the weight increase, relative to control samples. The active fraction was characterized by inorganic and organic content, as well as trace metal content iron, manganese, nickel, and cadmium. Subsequently, the active fraction was separated further using high-performance liquid chromatography, and the components thus separated were characterized by ultraviolet absorption spectra and by their effect on the size distribution of Chlamydomonas reinhardii. One component that showed significant bioactivity according to this assay was subjected to mass spectrometry. The maximum molecular ion for this component was less than 500. The available evidence is consistent with an aromatic molecule that contains a carboxylic acid. Further evidence includes the infrared spectra and the observation that all activity was lost when the sample was passed over an anion-exchange resin, whereas no activity was lost when the sample was passed over a cation-exchange resin.
- Civil Engineering