Improving zinc phytoremediation characteristics in Salix pedicellata with a new acclimation approach

Abstract

Salix sp. (willows) is a phytoremediator plant species that can accumulate and detoxify soils contaminated with pollutants and toxic heavy metals such as zinc. However, high concentrations of zinc inhibit plant growth and reduce biomass accumulation. In an attempt to overcome this inconvenience and to enhance plant adaptive abilities to zinc toxicity, we tested a new phytoremediation procedure in two clones of Salix pedicellata, named SPK-12 and SP-K20. The approach comprises two successive phases. The first is an "induction phase" consisting of gradual exposure of plants to low concentrations of zinc sulfate (ZnSO 4) at short and regular intervals. And, the second is a "maintenance phase" to uphold the acquired tolerance to zinc as long as possible. One of the two clones, SP-K20, tolerated up to 20 mg/L ZnSO 4 over 33 days without noticeable symptoms of chlorosis or growth inhibition. The SP-K20 clone was also able to accumulate high concentrations of zinc in its tissues, suggesting that phytoremediation abilities of Salix have been improved throughout the applied approach.

Adsorption of Mercury and Zinc in Agricultural Soils by <i>Sphagneticola trilobata</i>

“…Besides, Salix pedicellata achieves a removal of up to 9.71 μg/g of Zn; in this species, high concentrations of Zn cause immediate wilting and the appearance of chlorosis (Amdoun et al, 2020).…”