Optimization of Melatonin to Mitigate Cadmium Stress at Seedling Level in Tomato

Abstract

Heavy metals are important environmental pollutants in nature. Crops and vegetables growing in soils contaminated with heavy metals have greater accumulation of heavy metals than those grown in uncontaminated soil. Melatonin is auxins like hormone which serves many physiological functions in plants and protects the plants from adverse environment through the up regulation of metabolic compounds and plays an important role in seed germination and heavy metal tolerance index at the seedling level. A study was undertaken to assess the optimum concentration for imposing cadmium stress and melatonin for mitigating Cd stress and improving seedling health index in tomato (PKM 1). Cadmium chloride (CdCl2 ) was used to impose cadmium (Cd) heavy metal stress in five different concentrations 10, 20, 30, 40 and 50 ppm of Cd. Seeds sown in 10 and 20 ppm Cd solution recorded 75 and 68 per cent germination respectively while 50 per cent germination was observed in 30 ppm Cd. Based on the results, 30 ppm Cd concentration was selected to induce Cd toxicity in laboratory and pot culture experiments for the mitigation of Cd. To optimize melatonin concentration for mitigation of Cd, different concentration of melatonin ranging from 25, 50, 100 and 250 ppm was applied as seed treatments with 30 ppm Cd. Different parameters of seedling health characters were observed. The result revealed that, seed treatment with 250 ppm of melatonin showed the maximum root length (3.7 cm), promptness index (51.2) and total dry matter production (0.284g/seedling) compared to other treatments. This laboratory experiment concluded that 30 ppm cadmium is optimum concentration to impose cadmium stress and 250 ppm melatonin is the optimum for mitigating Cd toxicity.

DOI

https://doi.org/10.29321/MAJ.2018.000185

Pages

471 - 475

Creative Commons

Copyright

© The Author(s), 2026. Published by Madras Agricultural Students' Union in Madras Agricultural Journal (MAJ). This is an Open Access article, distributed under the terms of the Creative Commons Attribution 4.0 License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited by the user.

Keywords