Physiological, Biochemical, and Genotoxic Effects of Wastewater on Maize Seedlings

Wastewater not only provides nutrients to the plant community but may cause abiotic stress conditions due to the presence of toxic substances. The present study was designed to explore wastewater-induced changes in maize seedlings using four different concentrations (0, 10, 50, and 100%) collected from three different sources, i.e., municipal wastewater (designated as MW), woolen mill wastewater (designated as WW) and polyvinylchloride wastewater (designated as PW) of the city of Bannu situated in Khyber Pakhtunkhwa, Pakistan. All physiological parameters such as germination, biomass, and length of maize seedlings gradually slowed down with the increase in wastewater concentration. Similarly, the photosynthetic pigments decreased, while an increase was calculated in Na+ and Ca++ and K+ ions in our present experiment. The malondialdehyde (MDA) and hydrogen peroxide (H2O2) contents as well as antioxidative enzymes such superoxide dismutase (SOD), peroxidase (POD), ascorbate peroxidase (APX), and catalase (CAT) upregulated in all treated samples, while total soluble proteins increased. Various wastewater sources also caused genotoxic effects as revealed by the appearance and disappearance of various bands at DNA and protein levels. The present study reveals that different sources of wastewater caused differential stresses in maize seedlings, which might be due to the presence of different stressful agents in them.