Evaluation of Zn Uptake by Helianthus annuus, in a Tropical Climate, Using Different Phytoremediation Strategies

Phytoremediation is a rapidly expanding process due to its technical and economic viability. The objective of this work was to evaluate the phytoremediation potential of Helianthus annuus in three cultivation media: artificially contaminated Catalão soil, hydroponics and roadside soil. In hydroponics, ZnCl₂ doses 0.32 mgL^{- 1}, 29.94 mgL^{- 1}, 60.06 mgL^{- 1}, 119.94 mgL^{- 1} were used. While in the artificially contaminated soil, the doses were 0 mgkg^{- 1}, 299 mgkg^{- 1}, 599 mgkg^{- 1}, 1498 mgkg^{- 1}. Physiological analyzes made it possible to demonstrate that treatments T3 and T4, with the highest concentrations of the metal, inhibited growth and promoted darkening of the roots. The highest Zn contents occurred in the aerial part. The results indicated that Helianthus annuus was classified as hyperaccumulator due to its ability to accumulate high levels of Zn mainly in artificially contaminated soil.