Abstract
Heavy metal tolerance and accumulation potential are the two characteristics most important for plant use in phytoremediation technologies. Therefore, the aim of the present study was to characterize the tolerance of Hylotelephium maximum from coastal drift line vegetation against the biogenous heavy metals Cu, Zn, and Mn and its metal accumulation potential in controlled conditions. Plants were propagated vegetatively and cultivated in an automated greenhouse in a vegetative state (Experiment 1; Cu, Zn, and Mn) and in flowering-inducing conditions (Experiment 2; Mn gradient). In Experiment 1, total shoot biomass was negatively affected only by Mn at 1.0 g L−1, but root growth was significantly inhibited by all metals at this concentration. Plants accumulated 250 mg kg−1 Cu, 3200 mg kg−1 Zn, and >11,000 mg kg Mn−1 in their leaves. In Experiment 2, only new shoot growth was significantly suppressed at 0.5 g L−1 Mn. At the highest concentrations, shoot biomass progressively declined at the level of inhibition of flower and stem growth. Visual toxicity symptoms of Mn appeared 2 weeks after full treatment on leaves of 2.0 g L−1 treated plants as black dots along the main veins and spread over the leaf surface with time. The maximum Mn accumulation capacity was reached in leaves (15,000 mg kg−1), together with a high translocation factor and bioconcentration factor. The obtained results suggest that the particular accession of H. maximum has very good potential for practical phytoremediation purposes.
Funder
University of Latvia project, “Functional diversity of ecosystems and their contribution to ecosystem services II”