Exogenous Melatonin Protects Canola Plants from Toxicity of Excessive Copper

• Published in: Russian journal of plant physiology 2018-11, Vol.65 (6), p.882-889
• Main Authors: Kholodova, V. P., Vasil’ev, S. V., Efimova, M. V., Voronin, P. Yu, Rakhmankulova, Z. F., Danilova, E. Yu, Kuznetsov, Vl. V.
• Format: Article
• Language: English
• Subjects: Accumulation; Biomedical and Life Sciences; Brassica; Carotenoids; Chlorophyll; Chloroplasts; Copper; Copper sulfate; Life Sciences; Lipid peroxidation; Lipids; Melatonin; Membranes; Oxidative stress; Peroxidation; Plant Physiology; Plant protection; Plant Sciences; Proline; Research Papers; Salts; Sulfates; Thylakoid membranes; Toxicity
• ISSN: 1021-4437; 1608-3407
• DOI: 10.1134/S1021443718060080

Physiological mechanisms of canola ( Brassica napus L., cv. Westar) plant protection afforded by melatonin (at 0.1–100 μM) from copper salts (at 10–100 μM) were studied. Plants were cultivated on Hoagland–Snyder medium. At the age of 5 weeks, they were subjected to melatonin, copper sulfate, or their combination for 7 days. It was found that excessive copper in a nutrient medium inhibited the dry biomass accumulation against the control by 25–85%. Copper sulfate diminished the content of chlorophylls and carotenoids and functional activity of the thylakoid membranes in the chloroplasts. It increased 2.0–2.5 times the lipid peroxidation (LPO) intensity and the proline level up to 20 times. Melatonin reduced the changes caused by copper, and the degree of the protection depended on melatonin and CuSO 4 concentrations. It was found that melatonin decreased the oxidative stress and proline accumulation, both induced by CuSO 4 . At first, we established the positive correlation (with the coefficient 0.8240) between the level of oxidative stress and proline content in the presence of CuSO 4 . Possible mechanisms of protection by melatonin and its biological role under conditions of technogenic stress are discussed.