Biochar alleviates Cd phytotoxicity by minimizing bioavailability and oxidative stress in pak choi (Brassica chinensis L.) cultivated in Cd-polluted soil

Muhammad Kamran; Zaffar Malik; Aasma Parveen; Yutong Zong; Ghulam Hassan Abbasi; Muhammad Tariq Rafiq; Muhammad Shaaban; Adnan Mustafa; Saqib Bashir; Muhammad Rafay; Sajid Mehmood; Muhammad Ali

doi:10.1016/j.jenvman.2019.109500

Biochar alleviates Cd phytotoxicity by minimizing bioavailability and oxidative stress in pak choi (Brassica chinensis L.) cultivated in Cd-polluted soil

J Environ Manage. 2019 Nov 15:250:109500. doi: 10.1016/j.jenvman.2019.109500. Epub 2019 Sep 9.

Authors

Affiliations

¹ Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, PR China.
² Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan; Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, PR China. Electronic address: zafar_agrarian@yahoo.com.
³ Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan.
⁴ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, PR China.
⁵ Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, PR China; Centre of Integrated Research in Basic Sciences, International Islamic University, Islamabad, 44000, Pakistan.
⁶ Department of Soil Science, Faculty of Agricultural Sciences and Technology, Bahauddin Zakariya University, Multan, 60800, Pakistan.
⁷ National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
⁸ Department of Soil and Environmental Sciences, Ghazi University, Dera Ghazi Khan, 32200, Pakistan.
⁹ Department of Forestry and Wildlife, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, Bahawalpur, 63100, Pakistan.
¹⁰ Department of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, PR China.

PMID: 31513996
DOI: 10.1016/j.jenvman.2019.109500

Abstract

The production of leafy vegetables such as Brassica chinensis L. in cadmium (Cd)-polluted soil causes serious threats to human health and food safety around the globe. A pot culture was established to examine the efficacy of rice-straw induced biochar (applied to soil at the rate of 0%, 2.5% and 5%, w/w) on growth, gaseous exchange attributes, antioxidative capacities and Cd uptake in pak choi (Brassica chinensis L.), when soil was spiked with Cd (CdCl₂) at 0, 5, 10 and 20 mg kg^-1 soil. The results revealed that Cd stress significantly (P < 0.05) reduced plant biomass and physiological attributes, and accumulated higher Cd concentrations in plant tissues with the increasing rate of Cd concentration in the soil. However, incorporation of biochar at 5% application rate prominently increased the shoot (98.27%) and root (85.96%) dry biomass, net photosynthesis (45.52%), transpiration rate (161.34%), stomatal activity (111.76%) and intracellular CO₂ concentration (32.25%) when Cd was added at 20 mg kg^-1 soil, relative to the respective treatment without biochar. Whereas, incorporation of biochar at 5% significantly reduced the bioavailable Cd by 16.64% under 20 mg kg^-1 soil, compared to respective Cd treatment without biochar.Similarly, Cd accumulation in shoots and roots was decreased by 42.49% and 29.23%, and thereby reduced leaf MDA and H₂O₂ contents by 21.45% and 31.28%, respectively, at 20 mg Cd kg^-1 spiked soil relative to without biochar amended soil. An increment was noticed in the activities of guaiacol peroxidase (POD), superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and glutathione (GSH) by 37.31%, 66.35%, 115.94%, 122.72% and 59.96%, respectively, with 5% biochar addition in 20 mg kg^-1 Cd spiked soil. Moreover, biochar induced a synergistic impact on plants by increasing soil alkalinization and thereby reducing Cd phytotoxicity throughimmobilization. Overall, results proposed that rice-straw biochar has an ability to restore Cd polluted soil and increased pak choi production and thereby reduced food security risks in polluted soil.

Keywords: Antioxidants; Cd bioavailability; Gas exchange attributes; Pak choi; Rice-straw biochar; Soil remediation.

MeSH terms

Biological Availability
Brassica*
Cadmium
Charcoal
Hydrogen Peroxide
Oxidative Stress
Soil
Soil Pollutants*

Substances

Soil
Soil Pollutants
biochar
Cadmium
Charcoal
Hydrogen Peroxide