Arsenic toxicity and salinity stress effects on macronutrient uptake in watercress Nasturtium officinale

Watercress (Nasturtium officinale), is a fast-growing, aquatic or semi-aquatic, perennial plant native to Europe and Asia, and one of the oldest known leaf vegetables consumed by humans. The agricultural and industrial effluent discharges are considered for arsenic contamination in natural waters. The aim of this study is to investigate the ability of watercress (Nasturtium officinale) to uptake macronutrient from aquatic environments with different levels of salinity and arsenic. The watercress was propagated and exposed to Epestin nutrient solution contaminated with sodium arsenate (Na2HAsO4.7H2O) at six concentrations (5, 10, 20, 40, 80, and 160 mg As.L−1), including the control without As contamination for 30 days period. In this experiment the salinity were 0, 10, 20, 40 and 80 millimolar NaCl (sodium chloride). The experiment was conducted using completely randomized design and three replications. The results showed that the arsenic and salinity treatments significantly decreased the concentrations of total nitrogen (N), phosphorus (P) and potassium (K) in plant. The maximum amounts of N, P and K are absorbed in the treatments with 0 mg As.L-1 and 0 millimolar sodium chloride (control). The least amounts of nitrogen, phosphorus and potassium observed in treatments with 160 mg As.L-1 and 80 millimolar NaCl (sodium chloride).

Keywords:

Nitrogen , Phosphorus , Potassium , Sodium arsenate , Sodium chloride