Biological effects of PAS TiO2 sol on disease control and photosynthesis in cucumber (Cucumis sativus L.)

This paper reports the biological effects of TiO2 sol derived from peroxotitanic acid solution (PAS TiO2 sol) on the control of plant diseases and growth regulation. The PAS TiO2 sol is a neutral, viscous aqueous colloid of TiO2 containing 1.6% TiO2 with a size of between 10-50 nm. Experiments were conducted under normal laboratory and greenhouse growing conditions. For the bactericidal effects of the PAS TiO2 experiments, TiO2 coated glass slides were inoculated with pathogenic bacteria in the laboratory. For the Greenhouse experiments on disease control and photosynthesis, all test plants (treatment block and control block) were inoculated with pathogenic bacteria. While plants in the treatment blocks were sprayed with PAS TiO2, plants in the control blocks were sprayed with water. X-ray diffraction (XRD) results demonstrated that the crystal form of TiO2 nano-particles was anatase. Results from greenhouse experiments using cucumbers showed that PAS TiO2 sol formed a well-spread, transparent, and sticky layer of TiO2 photo-catalyst on the plants' surface. The PAS TiO2 photo-catalyst layer prevented pathogenic infection and improved photo synthetic performance. These results suggest that PAS TiO2 sol can be used as a potentially environmentally friendly plant germicide and growth regulator.