University Of Tehran Press Pollution 2383-451X 9 2 2023 02 01 Chromosomal and Nuclear Alteration Induced by Nickel Nitrate in the Root Tips of Allium cepa var. aggregatum 702 711 90765 10.22059/poll.2022.349167.1634 EN Made Pharmawati Biology Study Program, Faculty of Mathematics and Natural Sciences, Udayana University, Jalan Raya Kampus Unud, Jimbaran, Badung, 80361, Bali, Indonesia 0000-0002-3064-4582 Luh Putu Wrasiati groindustrial Technology Study Program, Faculty of Agricultural Technology, Udayana University, Jalan Raya Kampus Unud, Jimbaran, Badung, Bali 80361, Indonesia Journal Article 2022 09 26 Nickel nitrate is a heavy metal known as an environmental contaminant due to its toxicity, long environmental half-lives, and capacity for bioaccumulation.  This study aims to determine chromosomal aberration, nuclear alteration, and cell death in Allium cepa var. aggregatum L. root caused by different nickel concentrations.  Roots of Allium cepa var. aggregatum were induced by soaking bulbs in water, then transferred to a solution containing nickel (Ni) at a concentration of 20 ppm, 30 ppm, and 40 ppm for 72 hours.  Root tip mitotic chromosome preparations were done by the squash method.  The chromosome was stained with aceto-orcein and chromosomal damages were observed under a microscope.  The results showed that the mitotic index decreased from 5.025% at control to 3.144%, 2.467%, and 2.181% at immersion with 20 ppm, 30 ppm 40 ppm nickel nitrate, respectively.  Anaphase and telophase indexes in roots with Ni treatments were lower than in control, suggesting that nickel inhibits cell division.  Nickel nitrate induced chromosomal damages and nuclear abnormalities, such as sticky chromosome, fragmented chromosome, chromosome bridge and chromosome laggard, micronuclei, binucleate and nuclear budding.  The percentage of chromosomal damage increases with a higher concentration of Ni.  In situ cell visualization showed that the higher the nickel concentration, the more coloured the root tips indicating high levels of cell death. https://jpoll.ut.ac.ir/article_90765_2a903c3076a027bb5fde23447faa4447.pdf