Genotoxicity of heavy metals on mung bean (Vigna radiata) seedlings and its alleviation by priming with their lower concentrations

Abstract

Due to urbanization and industrialization, heavy metals have become the common environmental pollutant throughout the world. Chromosomal studies are one of the important tools to estimate the genome damaging property of these metals. This research was done to analyze the genotoxic effects of metals such as cadmium (Cd), nickel (Ni), mercury (Hg), lead (Pb) and copper (Cu) in mung bean (Vigna radiata) root tips. The experiment was set in such a way that mild metal treatment (0.01 mM) was given before respective high metal treatments (0.1 and 0.5 mM) separately, with the aim to know whether low/mild metals can alleviate metal tolerance in mung bean seedlings. Results demonstrated that metals treatment resulted in growth and mitotic index reduction. Among all the tested metals, Cd was found to cause more negative effect on growth of mung bean seedlings with length of 6.12 cm and 13.41% mitotic Index (MI) with the highest total aberrations (27.91%) at 0.5 mM Cd. Positive correlation was found between mitotic index and seedling length while a negative correlation was recorded between chromosomal aberrations with mitotic index and seedling length. Among these abnormalities C-mitosis, sticky chromosomes, and disturb metaphase were the most common aberrations irrespective of the metal. Furthermore, it was also observed that seed priming with respective mild metal concentration improves the seedling length, MI, and reduces the effect of metal stress by lowering the chromosomal aberrations in both 0.1 mM and 0.5 mM concentrations as compared to metal stress alone.