Effects of sodium and potassium chlorides on the growth and accumulation of mineral ions by Cyperus involucratus Rottb.

The response of the large emergent aquatic plant Cyperus involucratus Rottb. to NaCl and KCl salinities was studied under glasshouse conditions. Growth was not affected greatly by 50 mM NaCl or 100 mM KCl, but plants treated with 100 mM NaCl or 200 mM KCl were stunted and showed symptoms of salt toxicity. NaCl salinity was more detrimental than KCl, and Cl was more damaging to plant growth than K, but less damaging than Na. Salinity had no effect on plant succulence. NaCl and KCl treatments caused a decrease in concentrations of Ca and Mg in plant tissue, and NaCl-stressed plants accumulated nitrate-N. Na was largely excluded from leaves, whereas K was not. Concentrations up to 4% Cl, 8% K and 2.3% Na (dry wt. basis) were recorded in above-ground plant organs. C. involucratus is potentially a useful plant for inclusion in aquatic plant filters to treat wastewaters, and harvestable parts of the plant (culms and leaves) had over 60% of the total plant K, Na and Cl. The results are discussed with respect to the use of C. involucratus in systems for wastewater reclamation.