Mutagenic effects of environmental industrial chemical agents in inducing cytogenetical changes in wheat

Abstract

Six environmental Industrial chemical agents belonging to three separate groups: aziridines [Metepa (0.4 and 0.2%) and Thiotepa (0.2 and 0.01%)], nitroso compounds [MNG (0.1 and 0.05%)] and alkane sulphonic esters [MMS (0.1 and 0.05%) and EMS (0.5%)] and used in textiles, drug manufacture and as chemosterilants were compared for their mutagenicity and related cytogenetical effects on two wheat varieties - a tetraploid, durum wheat var. HD 4502 and a hexaploid bread wheat var. NP 880. Reduction In germination, survival, root and shoot length under the chemical treatments were observed In both the varieties, the tetraploid var. HD 4502 showing more sensitivity than the hexaploid var. NP 880. Among the chemicals Thiotepa followed by MNG showed drastic reduction in all the characters studied in M1 generation. They also showed drastic effects in terms of cytological parameters eg., cell division and chromosomal aberrations. High mutagenic effectiveness of Thiotepa was also indicated by the absence of any dividing cells in the sensitive var. HD 4502 and very high frequency of abnormal cells, clumping and chromosome breakage In hexaploid var. NP 880. Higher frequency and wider spectrum of viable mutations was also observed In var. HD 4502. On the overall basis (varieties pooled over mutagens) highest number of abnormal cells and shattering of chromosomes were observed under Metepa followed by Thiotepa. The other two chemical agents, MNG and MMS also exhibited larger chromosomal abnormalities than EMS and controls. Thus the present studies clearly demonstrate that environmental chemicals are much more potent mutagenic agents which couid also prove to be hazardous to human health due to their genotoxlc and carcinogenic properties.