Response of Miscanthus sinensis to prolonged applications of chromium in hydroponics

Plants of miscanthus were exposed for 104 days to chromium concentrations ranging from 19 to 76 mg L-1 in hydroponics. Plant growth was slightly enhanced with 19 mg Cr L-1, was decreased by approximately 16% with 38 and 57 mg Cr L-1, and by 34% with 76 mg Cr L-1. Root biomass and root length were increased with all Cr levels, whereas root diameter was decreased. Chromium caused the immediate acidification of the nutrient solution. After a two-week permanence of roots in solution a further decrease of pH Occurred with Cr levels between 19 and 57 mg L-1. In all plant parts the Cr concentration increased with increasing Cr supply, but the Cr concentrations of roots and rhizomes always exceeded by a 100 factor that of the shoot. Miscanthus plants accumulated between 217 and 507 mg Cr per plant, 99% of which was allocated in the hypogeal part.