Poster Number 584
Tuesday, 7 October 2008
George R. Brown Convention Center, Exhibit Hall E
Perennial veldt grass (Ehrharta calycina) threatens native grass and shrub species in coastal California, often reducing diverse, functioning ecosystems to veldt grass monocultures soon after it becomes established. This study evaluated its roots to determine whether the roots formed mycorrhizal relationships with fungi, and whether the root hairs accelerate mineral weathering of the sandy soils. We sampled areas of veldt grass infestation within a sandy site to evaluate the roots. Observation of stained roots under a stereoscopic microscope and environmental scanning electron microscope (E-SEM) showed no mycorrhizal relationships. Observation of sand grains under an E-SEM showed etching where roots hairs had contact. Root hair etching was most prominent on K-feldspar minerals. These studies suggest that Ehrharta calycina root hairs secrete acids that dissolve certain minerals to make the nutrients in those minerals more available. Perennial veldt grass is currently invading sand dune ecosystems in California, and there is concern that it will alter nutrient availability or competitive dynamics of coastal ecosystems.
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