Influence of nutrient medium composition on uranium toxicity and choice of the most sensitive growth related endpoint in Lemna minor

摘要

Uranium (U) toxicity is known to be highly dependent on U speciation and bioavailability, To assess the impact of uranium on plants, a growth inhibition test was set up in the freshwater macrophyte Lemna minor. First growth media with different compositions were tested in order to find a medium fit for testing U toxicity in L. minor. Following arguments were used for medium selection: the ability to sustain L. minor growth, a high solubility of U in the medium and a high percentage of the more toxic U-species namely UO22+. Based on these selection criteria a with a low phosphate concentration of 0.5 mg L-1 and supplemented with 5 mM MES (2-(N-morpholino)ethanesulfonic acid) to ensure pH stability was chosen. This medium also showed highest U toxicity compared to the other tested media.