Cadmium uptake and growth inhibition in water hyacinths: Effects of nutrient solution factors

Abstract

Cadmium (Cd) uptake and distribution in water hyacinth plants were studied in relation to growth and modifications in different solution factors (Cd concentration, Ca concentration and pH). Cadmium accumulation rates by roots were two to five times higher than those by leaves (including petioles) when Cd concentrations in the solution ranged from 0 to 10 ppm. The increase in the external concentration of Cd resulted in increased accumulation rates both by leaves and roots. The total content of Cd in roots was higher than that in leaves only when external concentrations of Cd were lower than 1.5 ppm. Cadmium reduced relative growth rates in both plant parts, particularly in roots. Cadmium concentrations that yielded growth reduction of 50% were 1.5, 9.9, and 5.8 ppm for roots, leaves and whole plant, respectively. Increased pH or reduced concentration of calcium (Ca) in the nutrient solution resulted in increased accumulation of Cd in roots, without affecting Cd accumulation in leaves.

Notes

Departamento de Biologia Vegetal, Universidade Federal de Viçosa, Brasil.

Departamento de Química, Universidade Federal de Viçosa, Brasil.