growth and nutrients concentration of duckweed (Lemna minor L.) as affected by cadmium and salinity application of aqueous solutions

A greenhouse experiment was conducted to study the effect of cadmium application on growth and nutrient concentrations in the duckweed under salinity conditions. The experiment was factorial arranged in a completely randomized design (CRD) with three replications. Factors were cadmium levels (0, 5, 10, 20,40, and 80 mg L-1 cd as cadmium sulfate) and salt concentration levels (0, 10, 20, 40, and 80 mM as sodium chloride) that added to Epstein nutrient solution. The results showed that cadmium and salinity, both alone and in combination, decreased relative growth rate of watercress. Cadmium concentration of duckweed increased by application of cadmium. Salinity increased cadmium concentration of duckweed. The application of cadmium and salinity, both alone and in combination, decreased nitrogen, phosphorus, potassium, calcium, magnesium, iron, zinc, copper, sodium concentration. Manganese concentration increased by cadmium but decreased by salinity. In conclusion, duckweed accumulated the high concentration of cadmium, as is a cadmium accumulator plant, although high concentration of cadmium and salinity were causing plant death.