Abnormal mitosis in root meristem cells of Allium cepa L. induced by a fabric dye reactive turquoise blue (Procion MX)

Abstract

Reactive Turquoise Blue (Procion MX) is a fabric dye used in small scale cotton fabric industries in various parts of India. The impact of this chemical on human health in the surrounding areas that discharge effluents is of serious concern. This needs to be assessed for short and long term effect on human genome. This investigation was aimed to find mitotic abnormalities as cytological evidence induced by the dye in root tip cells of onion (Allium cepa L.) grown in different concentrations: 0.01, 0.05, 0.1, 0.5 and 1.0% (weight per volume) prepared in distilled water in separate treatment schedules for 24 and 48 h. Mitotic aberrations (MA) were scored after staining with 2% acetocarmine by conventional squashing method. Root growth at various concentrations and duration of exposure of the dye were analyzed as macroscopic parameter for testing the cytotoxicity. Percentages of mitotic cells were analyzed as microscopic parameter to find the trend of mitotic indices and depression. Total abnormality of cells in percentage indicated the genotoxic assault of the dye. At higher concentrations, the root tip cells died in 24 h. Highest number of dividing cells with largest mitotic index value was observed at 0.01% exposed for 48 h. The abnormalities of common occurrences observed were unequal cytokinesis/ karyokinesis, formation of micronuclei, bi-nucleated cells and little condensed chromosomal arms in abnormal metaphase, anaphase and telophase. The abnormal mitotic cells were assumed to be due to genotoxic assault of the dye on chromosomal condensation mechanism resulting in very unusual long arms in rapidly dividing meristematic cells.

Keywords: Reactive torquoise blue, genotoxicity, Allium cepa, mitotic aberration

African Journal of Biotechnology, Vol 13(38) 3881-3891