Chromium Induces Genotoxicity in Root Tip Cells of Grass pea (Lathyrus sativus L., Variety Nirmal): A ROS-mediated Acute Toxicity Study

Background: Heavy metal-induced pollution of water bodies has emerged out as a major environmental menace for the modern world in the twenty first century. Many industrial waste waters contain heavy metals including Chromium, which plays a major role in polluting our water and agricultural sustainability in the long run. Due to heavy anthropogenic manoeuvres chromium is released as a waste product from various industries such as electroplating, battery and smelters, leather tanning, textile printing etc. The compounds of Chromium have been known to be strong carcinogens and mutagens that can reach the target organs of human through drinking water and agricultural crops. Chromium is often admixed with industrial effluents that are used for irrigation. Purpose: The uptake of excess concentrations of heavy metals through this effluent irrigation adversely affects plant growth and development. The alternation in plant growth is correlated with the disruption of the physiological disturbances and genotoxicity in plant cell. Results: After the exposure to chromium at five concentrations (12.5, 10, 7.5, 5, and 2.5 mM) respectively the seed germination was adversely affected along with root length inhibition. At higher doses (5 mM onwards) chromium exhibited nucleolar disintegration (by AgNOR protein leaching). In germinating root tip cells above suboptimal concentration (2.5 mM) chromium stands out as potential Phyto-genotoxicant with other toxic effects i.e., lipid peroxidation, electrolyte leakage due to membrane disruption, ROS generation (histological staining of hydroxyl and superoxide radical generation) root cell apoptosis (by Evans blue staining) and disruption of root metabolic activity by inhibition of dehydrogenase activity (by 2,3,5-Triphenyl tetrazolium chloride (TTC) staining methods). Conclusion: These observations constitute a warning signal about the risks of the widespread and increasing presence of chromium into environment especially in agricultural point of view which demands a high throughput evaluation of chromium for its effects on other organisms, even on human health, due to large use of chromium compounds in different gadgets. Lathyrus sativus L. is an excellent model plant for the study of environmental ecotoxicology of different genotoxicants. Implication: Regulatory monitoring and assessment of plant health is necessary for the better understanding of mechanism of action of chromium and to reduce Cr contamination through seeds and the resultant vital genome loss is cash crops.