ASSESSMENT OF GENOTOXIC EFFECTS PRODUCED BY HYPOXIA AND THERMAL STRESS IN MERISTEMATIC CELLS OF Allium cepa GERM ROOTS.

CANGIANO MA, GALLARDO L, JOFRÉ M.

BIOCELL

INST HISTOL EMBRIOL-CONICET

Lugar: Mendoza; Año: 2015 vol. 39 p. 188 - 188

0327-9545

The Alliun cepa root chromosome aberrations and micronucleus test is a widespread bioassay for genotoxicity assessment. Different protocols of this bioassay employ meristematic tissue obtained from bulbs of A. cepa, which are placed in treatment solutions, with continuous aeration. Chromosomal aberrations as C - mitosis, fragments and micronuclei have been observed in meristematic cells obtained from bulbs of A. cepa exposed to tap water, under hypoxic conditions. Given the need to assess the genotoxicity of chemicals and plant extracts available in small quantities, a test with germinal roots of A. cepa seeds has been developed. The aim of this study was to analyze the genotoxic effect of hypoxia andlow temperature in germ root meristematic cells of A. cepa. Seeds of A. cepa were placed to germinate in distilled water under three conditions: a) in a BIOESNAKY seed germinator, b) in Petri dish under hypoxia c) in Petri dish with aeration, in all three cases at two temperatures: 19 °C and 25 °C. Roots obtained from each treatment, were fixed, stained, and squashed in order to get mitotic slides. Meristematic cells in all treatments at 19 °C, showed a decrease in the mitotic index (MI) and karyolysis. Cells obtained from roots germinated at 25 °C showed an increase of MI compared with 19 °C and exhibited chromosomal aberrations (AC) as sticky chromosomes, C - mitosis and chromosome loose, among others. From these first experimental resultswe conclude that low temperature stress delays the physiological and biochemical mechanisms involved in the initial stage of germination decreasing the IM and causing karyolysis; also hypoxic conditions cause AC. To perform correctly his genotoxicity bioassay, from seeds, it is necessary to maintaina temperature of 23 °C to 25 °C and optimal oxygen availability. Future studies will assess which is the optimal oxygen availability to avoid false positives.