Effect of nano-TiO2 on strength of naturally aged seeds and growth of spinach

The effects of nano-TiO₂ (rutile) and non-nano-TiO₂ on the germination and growth of naturally aged spinach seeds were studied by measuring the germination rate and the germination and vigor indexes of aged spinach seeds. An increase of these factors was observed at 0.25–4‰ nano-TiO₂ treatment. During the growth stage, the plant dry weight was increased, as was the chlorophyll formation, the ribulosebisphosphate carboxylase/oxygenase activity, and the photosynthetic rate. The best results were found at 2.5‰ nano-TiO₂. The effects of non-nano-TiO₂ are not significant. It is shown that the physiological effects are related to the nanometer-size particles, but the mechanism by which nano-TiO₂ improves the growth of spinach seeds still needs further study.