Study regarding the cytotoxic potential of cadmium and zinc in meristematic tissues of basil (Ocimum basilicum L.)

The cytogenetic study on the meristematic tissues of basil (Ocimum basilicum L.) aimed to evaluate some cytotoxic effects induced by two heavy metals (cadmium - Cd and zinc - Zn) applied in three different concentrations: 10, 50 and 100 ppm. Cytogenetic tests reveal a decrease of the mitotic index and the occurrence of various chromosomal aberrations following heavy metal treatments. The cell division was significantly affected, especially in the case of Cd treatment, which showed the highest degree of toxicity in all variants compared to control variant. Instead, Zn has a lower degree of toxicity but only at concentrations of 50 ppm and 100 ppm. Types of chromosomal aberrations were relatively varied, being randomly distributed and concentration dependent, for both Cd and Zn. Were observed cells with large nucleus and disorganized-looking; interphases with pyknotic nucleus; cells with laggard chromosomes, pyknotic and sticky chromosomes, as well as cells with telophase bridge. The results reveal that Cd (at all tested concentrations) and Zn in concentrations higher than 10 ppm exhibit significant cytotoxic potential to Ocimum basilicum L. as a result of the effects reported in cell divisions of the meristematic tissues. We can also appreciate that the Ocimum basilicum L. species could be used as a test plant to determine the degree of soil pollution with heavy metals.