Detection of chromosomal aberration due to heavy metal NiNO3 on onion root tips

Chromosome aberration is a change in the number, structure  and the arrangement of chromosomes or sequence of genes in a chromosome that occurs due to physical, chemical and biological factors that cause abnormalities in individuals. Some environmental pollutants can cause damage to chromosomes, one of which is heavy metal. This study aims to determine the concentration of NiNO3 which has a toxic effect on the onion chromosomes, determine the type of damage / aberration of chromosomes that occur due to heavy metals Ni and analyze the effect of NiNO3 on the mitotic index. Onion (allium cepa) is a suitable plant model for this study because their chromosomes are large and easily observable. NiNO3 treatments given are 0 ppm, 10 ppm, 20 ppm and 30 ppm. Onion bulbs are rooted first by soaking the base in water. After the roots have grown 1 cm in length, the onion is transferred to a solution containing heavy metals Ni. The treatment is given for 24 hours. Chromosome preparations are prepared by the squash method. Root tip cut along 1 cm at 07.00-10.00. Chromosome staining is done with aceto-orcein coloring. Chromosome damage was observed under a microscope and determined the type of chromosome damage that occurred and the percentage of chromosomes that were damaged.