Phytoextraction of zinc, zinc oxide, copper and copper oxide in hydroponic solution with gibberellic acid and EDDS amendments by Lolium perenne

This work was focused on the phytoextraction of zinc, copper, zinc oxide and copper oxide by Lolium perenne cultivated in hydroponic conditions, with gibberellic acid (GA) and ethylenediamine-N,N’-disuccinic acid (EDDS) amendments tested separately and in combination. GA is a plant hormone which permits a better uptake of trace elements by increasing the biomass of shoots and the transpiration. EDDS is a chelator permitting to the metal to complex and cross physiological barriers. These two amendments were tested separately and in combination because a good synergy effect should be observed. The duration of treatment was first 11 days and then 28 days. The enzyme activity of catalase and ascorbate peroxidase was measured. The results showed a higher uptake for zinc with the GA treatment, where the final quantity after 21 days was 24 μg instead of 14 μg for the control, and the translocation index was 0.3 instead of 0.1 for the control. For copper the best results were obtained with EDDS, which gave a quantity of 4.5 μg after 28 days instead of 3.5 μg for the control and the translocation index was 0.275 instead of 0.12 for the control. For the metal oxides the results were less significant, especially for enzyme activities. Finally a hydric stress was observed after 28 days, cumulated with metal stress.