Cadmium mediated phytotoxic impacts in Brassica napus: Managing growth, physiological and oxidative disturbances through combined use of biochar and Enterobacter sp. MN17

Asma Sabir; Muhammad Naveed; Muhammad Asaad Bashir; Azhar Hussain; Adnan Mustafa; Zahir Ahmad Zahir; Muhammad Kamran; Allah Ditta; Avelino Núñez-Delgado; Qudsia Saeed; Abdul Qadeer

doi:10.1016/j.jenvman.2020.110522

Cadmium mediated phytotoxic impacts in Brassica napus: Managing growth, physiological and oxidative disturbances through combined use of biochar and Enterobacter sp. MN17

J Environ Manage. 2020 Jul 1:265:110522. doi: 10.1016/j.jenvman.2020.110522. Epub 2020 Apr 7.

Authors

Affiliations

¹ Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan; School of Environmental Sciences, University of Guelph Ridgetown Campus, Ridgetown, N0P 2C0, Canada.
² Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan. Electronic address: muhammad.naveed@uaf.edu.pk.
³ Department of Soil Science, University College of Agriculture and Environmental Sciences, The Islamia University of Bahawalpur, 63100, Pakistan.
⁴ Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan; National Engineering Laboratory for Improving Quality of Arable Land, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
⁵ Institute of Soil and Environmental Sciences, University of Agriculture, Faisalabad, 38040, Pakistan.
⁶ Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, Huazhong Agricultural University, Wuhan, 430070, China.
⁷ Department of Environmental Sciences, Shaheed Benazir Bhutto University Sheringal, Upper Dir, Khyber Pakhtunkhwa, Pakistan.
⁸ Dept. Soil Sci. and Agric. Chem., Engineering Polytech. School, Campus Univ. Lugo, Univ. Santiago de Compostela, Spain.
⁹ College of Natural Resources and Environment, Northwest Agriculture and Forestry University, Yangling, 712100, China.
¹⁰ Key Laboratory of Geographic Information Science of the Ministry of Education, School of Geographical Sciences, East China Normal University, Shanghai, 200241, China.

PMID: 32275244
DOI: 10.1016/j.jenvman.2020.110522

Abstract

Cadmium (Cd) is a toxic heavy metal with unknown biological role. Interactive effect of Enterobacter sp. MN17 and biochar was studied on the growth, physiology and antioxidant defense system of Brassica napus under Cd contaminated soil. A multi-metal tolerant endophytic bacterium, Enterobacter sp. MN17, was able to grow in tryptic soy agar (TSA) medium with up to 160, 200, 300, 700, 160 and 400 μg mL^-1 of Cd, Cu, Cr, Pb, Ni and Zn, respectively. Paper and pulp waste biochar was prepared at 450 °C and applied to pots (7 kg soil) at a rate of 1% (w/w), while Cd was spiked at 80 mg kg^-1 soil. Application of Enterobacter sp. MN17 and biochar, alone or combined, was found effective in the amelioration of Cd stress. Combined application of Enterobacter sp. MN17 and biochar caused the maximum appraisal in shoot and root length (52.5 and 76.5%), fresh and dry weights of shoot (77.1 and 70.7%) and root (81.2 and 57.9%), photosynthetic and transpiration rate (120.2 and 106.6%), stomatal and sub-stomatal conductance (81.3 and 75.5%), chlorophyll content and relative water content (RWC) (78.4 and 102.9%) than control. Their combined use showed a significant decrease in electrolyte leakage (EL), proline, malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GPX), glutathione S transferase (GST) and superoxide dismutase (SOD) by 39.3, 39.4, 39.5, 37.0, 39.0 42.1 and 30.8%, respectively, relative to control. Likewise, the combined application of bacterial strain MN17 and biochar reduced Cd in soil by 45.6%, thereby decreasing its uptake in root and shoot by 40.1 and 38.2%, respectively in Cd contaminated soil. The application of biochar supported the maximum colonization of strain MN17 in the rhizosphere soil, root and shoot tissues. These results reflected that inoculation with Enterobacter sp. MN17 could be an effective approach to accelerate biochar-mediated remediation of Cd contaminated soil for sustainable production of crops.

Keywords: Biochar; Cadmium; Contaminated soils; Crop production; Enterobacter sp. MN17; Remediation.

MeSH terms

Brassica napus*
Cadmium
Charcoal
Enterobacter
Oxidative Stress
Soil
Soil Pollutants*

Substances

Soil
Soil Pollutants
biochar
Cadmium
Charcoal