Zinc-lysine Supplementation Mitigates Oxidative Stress in Rapeseed (Brassica napus L.) by Preventing Phytotoxicity of Chromium, When Irrigated with Tannery Wastewater

Ihsan Elahi Zaheer; Shafaqat Ali; Muhammad Hamzah Saleem; Muhammad Arslan Ashraf; Qurban Ali; Zohaib Abbas; Muhammad Rizwan; Mohamed A El-Sheikh; Mohammed Nasser Alyemeni; Leonard Wijaya

doi:10.3390/plants9091145

Zinc-lysine Supplementation Mitigates Oxidative Stress in Rapeseed (Brassica napus L.) by Preventing Phytotoxicity of Chromium, When Irrigated with Tannery Wastewater

Plants (Basel). 2020 Sep 4;9(9):1145. doi: 10.3390/plants9091145.

Authors

Affiliations

¹ Department of Environmental Sciences and Engineering, Government College University Allama Iqbal Road, Faisalabad 38000, Pakistan.
² Department of Biological Sciences and Technology, China Medical University, Taichung 40402, Taiwan.
³ MOA Key Laboratory of Crop Ecophysiology and Farming System Core in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
⁴ Department of Botany, Government College University Faisalabad, Faisalabad 38000, Pakistan.
⁵ Key laboratory of Plant Pathology, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
⁶ Department of Botany and Microbiology, College of Science, King Saud University, 11451 Riyadh, Saudi Arabia.

Abstract

Contamination of soil and water with metals and metalloids is one of the most serious problems worldwide due to a lack of a healthy diet and food scarcity. Moreover, the cultivation of oilseed crops such as rapeseed (Brassica napus L.) with tannery wastewater could contain a large amount of toxic heavy metals [e.g., chromium (Cr)], which ultimately reduce its yield and directly influence oilseed quality. To overcome Cr toxicity in B. napus, a pot experiment was conducted to enhance plant growth and biomass by using newly introduced role of micronutrient-amino chelates [Zinc-lysine (Zn-lys)], which was irrigated with different levels [0% (control), 33%, 66%, and 100%] of tannery wastewater. According to the results of present findings, very high content of Cr in the wastewater directly affected plant growth and composition as well as gas exchange parameters, while boosting up the production of reactive oxygen species (ROS) and induced oxidative damage in the roots and leaves of B. napus. However, activities of antioxidants initially increased (33% of wastewater), but further addition of tannery wastewater in the soil caused a decrease in antioxidant enzymes, which also manifested by Zn content, while the conscious addition of wastewater significantly increased Cr content in the roots and shoots of B. napus. To reduce Cr toxicity in B. napus plants, exogenous supplementation of Zn-lys (10 mg/L) plays an effective role in increasing morpho-physiological attributes of B. napus and also reduces the oxidative stress in the roots and leaves of the oilseed crop (B. napus). Enhancement in different growth attributes was directly linked with increased in antioxidative enzymes while decreased uptake and accumulation of Cr content in B. napus when cultivated in wastewater with the application of Zn-lys. Zn-lys, therefore, plays a protective role in reducing the Cr toxicity of B. napus through an increase in plant growth and lowering of Cr uptake in various plant organs. However, further studies at field levels are required to explore the mechanisms of Zn-lys mediated reduction of Cr and possibly other heavy metal toxicity in plants.

Keywords: antioxidant enzymes; growth; heavy metals; micronutrient-amino chelates; oil seed crop.