The Bioremediation Potential of Perennial Ryegrass (Lolium perenne L.) in the Presence of Cadmium or Copper

Our main goal was to determine whether the accumulation of Cd and Cu is harmful for L. perenne or whether this plant can be used in the bioremediation, e.g., of wastewaters or contaminated soils. The IC50 values (concentration at which the tested parameter is inhibited to 50% against the control) for root and shoot inhibition after 14 days showed that Cu, as an essential element for plants, was more toxic than Cd. The translocation factor (TF), which refers to metal transport from the root to the shoot, did not exceed values of 0.228 and 0.353 for Cd and Cu, respectively, indicating their accumulation mostly in the roots rather than in the shoots. The protein thiol (-SH) groups as a parameter of the increased level of reactive oxygen species did not confirm the significantly higher level of oxidative stress for Cu, which is a redox-active cation. We confirmed a statistically significant positive correlation between -SH groups and chlorophyll a (r = 0.79; p < 0.05) and chlorophyll b (r = 0.84; p < 0.01) in the presence of Cd. We concluded that bioaccumulation of the tested metals occurred mostly in the roots, and the photosynthetic pigment content in the shoots was not significantly impaired by the increased presence of Cd or Cu in the shoots. Therefore, we suggest L. perenne as a suitable candidate for the phytomining or phytoextraction of metals, mostly from wastewater, in cooperation with other plant hyperaccumulators.