Student Research Reports

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The aim of this project was to determine the differences in water quality from different stations and their influence on changes in mitosis and on the number and growth intensity of Allium cepa L. roots. We determined the pH of water, dissolved oxygen, nitrate, nitrite, ammonia and phosphate ions. In this project, we have proved our assumption that there are differences in water quality in physical and chemical parameters between tap water, water from Jelenovac stream, lakes Jarun and Bundek and the Sava River. For each sample of water, five bulbs were placed in the examined water with their basal parts. After 14 days the roots were counted and measured. By microscopic observation of the root tips sections were determined mitosis phases and we calculated the mitotic index. Chromosomal abnormalities were also evaluated. Root lenghts were smaller in water having lower quality. The contaminated water caused decreased mitotic activity and increased the occurrence of chromosomal aberrations in the root cells. The project has shown slow growth of root tips and the smallest number of roots in the water of the Sava River. According to the measured physico-chemical parameters, the water from the Sava River was the most polluted, the mitotic index was the smallest and the number of aberrations was the greatest.