Effect of waste water treated with TiO2 nanoparticles on early seedling growth of Zea mays L.

Abstract

The present investigation was to determine the effect of nano-TiO2 (2 to 6 nm) and waste water on early seedling growth of maize. The suspensions of nano-TiO2 either in deionized water or autoclaved waste water were applied at 100 mg/L, 50 mg/L and 25 mg/L under in vitro conditions. Analyses of waste water showed that it was not suitable for irrigation purposes as it had a higher content of heavy metals (Fe, Mn, Zn, Cd, Cr and Cu) which were above permissible levels for irrigation. The higher concentration of nano-TiO2 (100 mg/L) and waste water significantly inhibited seed germination, seedling growth and caused accumulation of phenolics in maize plants (p < 0.05). The application of nano-TiO2 at 25 mg/L significantly increased shoot fresh weight, shoot dry weight, root fresh weight, root dry weight, root area, chlorophyll a, chlorophyll b and carotenoids content (p < 0.05). The adverse effects of waste water on growth attributes of maize were significantly ameliorated by nano-TiO2 at 25 mg/L (p < 0.05). The treatment of waste water with nano-TiO2 (25 mg/L) is recommended before its utilization for agriculture purposes.

Keywords

• nano-TiO2
• phenolics
• phytotoxicity
• waste water
• water reuse