Combined metal treatments cause marked changes in the ionomic patterns in Szarvasi-1 energy grass shoot biomass

Abstract

Background and aims

Trace metal (TM) contamination has been and still is a major environmental threat as pollutants are frequently released to the environment through various channels. High biomass plants used for energy production can be a good option for decontamination or stabilization of soils. In the present study we have tested Szarvasi-1 energy grass (Elymus elongatus subsp. ponticus cv. Szarvasi-1) under single or combined treatment with three TMs (Cu, Cd, and Pb) in three concentrations aiming to reveal bioaccumulation and ionomic characteristics.

Methods

The plants were grown in soil spiked with Cd, Cu and Pb in single or combined treatments. Physiological and elemental data were collected, and the changes were evaluated using several multivariate analyses.

Results

Germination, growth, chlorophyll (Chl) content and photochemical reflectance index (PRI) declined in the Pb < Cu ~ Cd order whereas the relative water content and malondialdehyde (MDA) content of the shoots were stable across the treatments. In the combined treatments the growth variables, Chl and PRI declined rapidly and MDA increased showing the exhaustion of detoxification capacity of the plant. The accumulation of TMs (bioconcentration factor) decreased in the following order Cd > Cu > Pb in both single and combined treatments but in the latter the accumulation pattern slightly changed in favour of Pb. The nutrient and trace elements showed a characteristic change in their pattern in the shoots.

Conclusions

Our study points to the limitations of the application of grasses such as Szarvasi-1 energy grass in phytoremediation projects conducted on soils with multiple metal contamination.