Phytotoxicity of Depleted Uranium on Three Grasses Characteristic of Different Successional Stages
- Michael C. Meyer * and
- Terry McLendon
In response to a paucity of data on the chemical toxicity of uranium (U) to plants, a factorial experiment employing five U concentrations (0, 50, 500, 5000, 25 000 mg kg−1) and three moisture regimes (low, medium, and high) was performed using three native grasses. Buchloe dactyloides (buffalograss; mid/late-seral), Schizachyrium scoparium (little bluestem; late-seral), and Aristida purpurea (purple threeawn; early/mid-seral) were grown in monocultures and as a mixture of two species under all combinations of U and moisture levels. This design allowed for the analysis of U effects, as well as possible interactions with moisture stress. Several measures of plant health and viability were made, including: percent emergence, plant survival, shoot biomass, and number and weight of inflorescences. Decreases in plant biomass, fecundity, and long-term survivability were observed only at the highest U level (25 000 mg kg 1). No significant differences (P < 0.05) between the U treatment levels were observed in terms of seedling emergence and survival. Drought stress also negatively impacted survival and biomass, but acted independently of U stress.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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