Growth and Cadmium Uptake of Miscanthus sinensis as Affected by Cadmium

Plants of the bioenergy crop Miscanthus sinensis var. Giganteus Greef et Deu. were grown for 104 days in nutrient solution with cadmium added at rates of 0, 0.75, 1.5 and 3 mg L-1. Cadmium re- duced total plant biomass by about 50% up to 1.5 mg L-1 and by 90% at 3 mg L-1, and affected shoot growth more than rhizome+root growth. In the shoots, cadmium reduced culm elongation and leaf emission, and hastened leaf senescence. Root size parameters were affected differently by the metal: length and surface area decreased more than volume and dry weight, whereas the average root diameter increased. Cadmi- um translocation within the plant was affected by the Cd level. In fact, the Cd concentration in both roots and rhizomes increased progressively with increasing Cd levels, but the increase was approximately ten times greater in roots than in rhizomes. In contrast, the Cd concentration in culms and dead leaves was in- dependent of Cd level and in green leaves it decreased with increasing amounts of Cd. Thus, the Cd con- tent of the whole plant increased from 2.3 to 3.4 mg plant-1 in response to rising levels of Cd, but the met- al content of the harvestable part (shoot+rhizome) was higher at the two lower Cd levels.