Assessment of Growth Promoting Ability of Three Cyanobacterial Isolates Under Sewage Water Irrigation

Abstract

Heavy metal pollution from the increased use of sewage effluent for irrigation is posing a hazard to agricultural ecosystems. Thus, a reliable and simple method of reducing the impact of heavy metals on plant growth is required. In the present study, cyanobacterial species were isolated from the sewage water irrigated soil of Rohtak city, Haryana, India, and characterized by various biochemical parameters. The cyanobacterial filtrates were then used to analyze their effects on the growth performance of rice seedlings under various concentrations of sewage wastewater. The results revealed a statistically significant increase in biomass, photosynthetic pigments, nitrate reductase activity, plumule, and radical length of rice seedlings by application of cyanobacterial filtrates. The antioxidant system (peroxidase enzyme and catalase enzyme activity) was also found to be stimulated. As compared to introduced species, the extracts of isolated species had a more favorable, statistically significant effect on rice seedlings. Our study indicated that these isolates have a high tolerance against heavy metals and are potentially useful as biofertilizers for the crops in sewage water irrigated agroecosystems.

Keywords

• heavy metals, cyanobacteria, photosynthetic pigments, rice seedlings, sewage water