Effects of zinc application on cadmium (Cd) accumulation and plant growth through modulation of the antioxidant system and translocation of Cd in low- and high-Cd wheat cultivars

Jun Zhou; Chen Zhang; Buyun Du; Hongbiao Cui; Xingjun Fan; Dongmei Zhou; Jing Zhou

doi:10.1016/j.envpol.2020.115045

Effects of zinc application on cadmium (Cd) accumulation and plant growth through modulation of the antioxidant system and translocation of Cd in low- and high-Cd wheat cultivars

Environ Pollut. 2020 Oct;265(Pt A):115045. doi: 10.1016/j.envpol.2020.115045. Epub 2020 Jun 18.

Authors

Jun Zhou¹, Chen Zhang², Buyun Du³, Hongbiao Cui⁴, Xingjun Fan⁵, Dongmei Zhou⁶, Jing Zhou⁷

Affiliations

¹ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China; College of Resource and Environment, Anhui Science and Technology University, Fengyang, Anhui, 233100, China.
² Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
³ Nanjing Institute of Environmental Sciences, Ministry of Ecological Environment, Nanjing, 210042, China.
⁴ School of Earth and Environment, Anhui University of Science and Technology, Huainan, 232001, China.
⁵ College of Resource and Environment, Anhui Science and Technology University, Fengyang, Anhui, 233100, China.
⁶ School of the Environment, Nanjing University, Nanjing, 210023, China.
⁷ Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China. Electronic address: zhoujing@issas.ac.cn.

PMID: 32593926
DOI: 10.1016/j.envpol.2020.115045

Abstract

Cadmium (Cd) contamination is a big challenge for managing food supply and safety around the world. Reduction of the bioaccumulation of cadmium (Cd) in wheat is an important way to minimize Cd hazards to human health. This study compared and highlighted the effects of soil and foliar applications of Zn on Cd accumulation and toxicity in cultivars with high Cd accumulation (high-Cd wheat) and low Cd accumulation (low-Cd wheat). Both foliar and soil Zn applications provided effective strategies for reducing wheat grain Cd concentrations in the high-Cd wheat by 26-49% and 25-52%, respectively, and these also significantly reduced the concentrations in wheat stems and leaves. Foliar and soil Zn applications significantly reduced Cd in leaves and stems of the low-Cd wheat but had no effects on grain Cd. Both soil and foliar Zn applications significantly alleviated Cd toxicity by regulation of Cd transport genes, as reflected by the increased grain yield and antioxidant enzyme activity in the wheat tissues. Gene expression in response to zinc application differed in the two wheat cultivars. Down-regulation of the influx transporter (TaNramp5) and upregulation of the efflux transporters (TaTM20 and TaHMA3) in the high-Cd wheat may have contributed to the Zn-dependent Cd alleviation and enhanced its tolerance to Cd toxicity. Additionally, foliar Zn applications down-regulated the leaf TaHMA2 expression that reduced root Cd translocation to shoots, while soil Zn applications down-regulated the root TaLCT1 expression, which contributed to the reduction of root Cd concentrations. Soil (99 kg ZnSO₄·7H₂O ha^-1) and foliar (0.36 kg ZnSO₄·7H₂O ha^-1) Zn applications can effectively decrease the Cd in grains and guarantee food safety and yield, simultaneously. The presented results provide a new insight into the mechanisms of, and strategies for, using Zn for the Cd reduction in wheat.

Keywords: Antioxidant enzymes; Bioconcentration factors; Genes expression; Micronutrient; Translocation factor.

MeSH terms

Antioxidants
Cadmium / analysis*
Humans
Soil
Soil Pollutants / analysis*
Triticum
Zinc / analysis

Substances

Antioxidants
Soil
Soil Pollutants
Cadmium
Zinc