Screening of Chinese mustard (Brassica juncea L.) cultivars for the phytoremediation of Cd and Zn based on the plant physiological mechanisms

Juan Du; Zhanyu Guo; Ronghua Li; Amjad Ali; Di Guo; Altaf Hussain Lahori; Ping Wang; Xiangyu Liu; Xuejia Wang; Zengqiang Zhang

doi:10.1016/j.envpol.2020.114213

Screening of Chinese mustard (Brassica juncea L.) cultivars for the phytoremediation of Cd and Zn based on the plant physiological mechanisms

Environ Pollut. 2020 Jun:261:114213. doi: 10.1016/j.envpol.2020.114213. Epub 2020 Feb 22.

Authors

Affiliations

¹ College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China.
² Key Laboratory of Ministry of Education on Pollution Control and Ecosystem Restoration in Industry Clusters, Guangdong Provincial Engineering and Technology Research Center for Environmental Risk Prevention and Emergency Disposal, School of Environment and Energy, South China University of Technology, Guangzhou, Guangdong, 510006, China.
³ Department of Environmental Sciences, Sindh Madressatul Islam University, Karachi, 74000, Pakistan.
⁴ College of Natural Resources and Environment, Northwest A&F University, Yangling, Shaanxi, 712100, China. Electronic address: zhangzq58@126.com.

PMID: 32408418
DOI: 10.1016/j.envpol.2020.114213

Abstract

Brassica juncea L. is an attractive species in PTMs contaminated soil remediation ascribing to its high tolerance under stress and great accumulation capacity of metals. To identify the potential Cd/Zn accumulators from numerous different Chinese mustard cultivars for practical phytoremediation is a promising strategy in China. In present work, a pot experiment involving elevated Cd/Zn concentrations was performed among 21 cultivars. Regarding physiological and biochemical indicators under Cd/Zn stress, principal component analysis and cluster analysis were used for cultivar tolerance evaluation and classification. Results showed that BJ (Bao Jie, var. involutus) cultivar was distinguished as a potential phytoremediation candidate comparing with other cultivars. Moreover, BJ accumulated the maximum Cd content of 63.85 and 77.29 mg kg^-1 DW in shoots and roots, respectively, and the maximum Zn uptake by BJ were 6693 and 4777 mg kg^-1 DW in shoots and roots, respectively. Accordingly, BJ had the highest Cd/Zn tolerance, remarkable accumulation and translocation capacity (accumulation factor (AF) > 1 for Cd and Zn; translocation factor (TF) > 0.8 for Cd and TF > 1 for Zn). In addition, the superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activities of the mustard increased initially under low Cd/Zn stress as compared to the control and then declined dramatically with the increasing metals exposure concentration. Therefore, the antioxidant enzymes may play a protective role against reactive oxygen species (ROS) under low Cd/Zn stress, whereas the defense system might be collapsed under relatively high Cd/Zn stress. Furthermore, the enhanced Cd/Zn exposure led to an increase in malondialdehyde (MDA) content in the mustard cultivars, indicating that Cd/Zn had induced more severe oxidative stress and higher degree of lipid peroxidation had occurred. The present investigation results indicated that BJ (Bao Jie, var. involutus), as a native cultivar, can be further applied in the field trials of phytoremediation practices in contaminated soil.

Keywords: Antioxidant enzymes; Chinese mustard; Phytoremediation; Tolerance index; Toxic metals.

MeSH terms

Antioxidants
Biodegradation, Environmental
Cadmium / analysis
Cadmium / metabolism*
China
Mustard Plant / metabolism*
Plant Roots
Soil Pollutants / analysis
Soil Pollutants / metabolism*
Zinc / analysis
Zinc / metabolism*

Substances

Antioxidants
Soil Pollutants
Cadmium
Zinc