Induced genetic variations in Cuminum cyminum through supplemental UV-B radiation

Aim: The present study was conducted to investigate the genotoxic effect of UV-B radiation on morphological, biochemical and cytological parameters of Cuminum cyminum. Methodology: The germinated roots of cumin were exposed to UV-B radiation at different intervals viz., 20 min 40 min and 60 min, respectively, and some treated seeds were sown on pots for morphological and biochemical observation. Results: Chromosomal studies divulged that UV-B radiation has substantial impact on Active Mitotic Index (AMI %). On increasing UV-B radiation dose, the chromosomal aberration rate elevated, thus AMI % moderately decreased and Total Abnormality percentage (TAB %) gradually increased. Different types of chromosomal abnormalities were ascertained, among which scattering was more prominent. The morphological observation showed that survival percentage and plant height decreased at elevated dose of UV-B. Biochemical results indicated that chlorophyll a, chlorophyll b and carotenoid contents decreased as compared to control, but proline content showed significant increment at higher doses of UV-B. Interpretation: The observation elucidates that UV-B causes chromosomal aberrations during cell division and acts as a potent genotoxic agents for roots. Thus, it can be concluded from the above experiment that UV-B rays promote plant growth at low doses but at the higher doses, it subsequently hinders plant growth by damaging important constituents of plant cell.