Parthenium hysterophorus Induced Genotoxic Hazards in Allium cepa L.

The paper deals with allelopathic effect of Parthenium hysterophorus L. extract on the meristametic cells of onion (Allium cepa L.). The ischolar_main tips of onion were treated with different concentrations (10%, 25%, 50%, 75%, 100%) of Parthenium extract for 4 hrs at room temperature. The Parthenium extract was prepared from plant parts such as leaf, stem, inflorescence and whole plant and the treated ischolar_main tips were squashed in freshly prepared 2% acetocarmine solution. The results revealed that Parthenium extract exerts mitotic depression causing chromosomal abnormalities such as fragments, stickiness, nuclear vacuolation, bridge, laggards and micronuclei. The mitotic abnormalities were gradually increased with increasing concentration of the extract. Percentage of abnormal cells varied from 9.58 (10% Parthenium stem) to 40.59 (100% Parthenium inflorescence). The gradation of genotoxicity of different parts of Parthenium were noted as inflorescence > whole plant > leaf > stem. Parthenium may be considered as a strong genotoxic agent. The suppression of DNA content due to the application of Parthenium is another potential threat to the genomic balance which may cause the deviation of normal metabolic activities from its original parental line.