Heavy metal accumulation and tolerance of energy grass (Elymus elongatus subsp. ponticus cv. Szarvasi-1) grown in hydroponic culture

• Shoot metal accumulation in Szarvasi-1 energy grass showed the order Pb < Ni < Cu ∼ Cd < Zn.
• Szarvasi-1 is a Zn accumulator plant with 300 mg kg−1 DW Zn in shoots.
• Zn increased shoot Fe and Chl concentrations and transpiration.
• Cu and Cd reduced growth, Chl concentration and transpiration.
• Cu and Cd caused Fe plaque formation in roots and microelement imbalance in shoots.

Phytoremediation is a plant based, cost effective technology to detoxify or stabilise contaminated soils. Fast growing, high biomass, perennial plants may be used not only in phytoremediation but also in energy production. Szarvasi-1 energy grass (Elymus elongatus subsp. ponticus cv. Szarvasi-1), a good candidate for this combined application, was grown in nutrient solution in order to assess its Cd, Cu, Ni, Pb and Zn accumulation and tolerance. Its shoot metal accumulation showed the order Pb < Ni < Cu ∼ Cd < Zn. In parallel with this, Pb and Ni had no or very little influence on the growth, dry matter content, chlorophyll concentration and transpiration of the plants. Cu and Cd treatment resulted in significant decreases in all these parameters that can be attributed to Fe plaque formation in the roots suggested by markedly increased Fe and Cu accumulation. This came together with decreased shoot and root Mn concentrations in both treatments while shoot Cu and Zn concentrations decreased under Cd and Cu exposure, respectively. Zn treatment had no effect or even slightly stimulated the plants. This may be due to a slight stimulation of Fe translocation and a very efficient detoxification mechanism. Based on the average 300 mg kg−1 (dry mass) Zn concentration which is 0.03% of the shoot dry mass the variety is suggested to be classified as Zn accumulator.