Zinc phytotoxicity and cationic micronutrients contents in quinoa as influenced by high Zn levels and soil amendments

Abstract

Contamination of soils with heavy metals (HMs) is a serious concern due to the non-biodegradability and accumulation of these metals in living organism. The aim of this study was to evaluate the effectiveness of fish scale powder, chitin, and chitosan in reducing zinc (Zn) accumulation of quinoa grown on Zn-polluted soil. A 3*4 factorial greenhouse trial was conducted with three levels of Zn contamination (0, 100, and 200 mg kg⁻¹) and four types of amendment (control, and 0.15% of each fish scale powder, chitin, and chitosan). The quinoa seeds were sown in soil treated with Zn contamination and amendments. Results showed that application of amendments especially chitosan increased shoot and root dry weight and greenness index of quinoa leaf. While high soil Zn levels decreased cationic micronutrients uptake in quinoa shoot, chitosan addition desirably enhanced cationic micronutrients uptake in quinoa shoot. Overall, amendment addition significantly decreased Zn concentration and uptake in plant; the highest decrease was observed following the application of chitosan. Although the application of high Zn levels significantly increased the values of phytoextraction efficiency, application of chitin and chitosan significantly decreased it. The value of translocation factor was lower than one, demonstrating that a large amount of Zn was stabilized in the root tissues, while a small amount of this metal was transferred to aboveground parts of quinoa. Results of this study revealed that fish scales derivatives were effective in preventing Zn toxicity and at the same time increasing cationic micronutrients contents of quinoa grown on HMs-polluted soil.

Keywords:

• Chitin
• chitosan
• fish scale
• immobilization
• quinoa
• zinc

Acknowledgments

Authors would like to appreciate Shiraz University for providing research facilities.

Disclosure statement

No potential conflict of interest was reported by the author(s).