Abstract:
Objective To explore the effect of TiO2 spraying agent on photosynthesis and chlorophyll fluorescence parameters of upper tobacco leaves, and provide a reference for improving the availability of upper tobacco leaves.
Method TiO2 spraying agent was preparated by means of sol-gel method. The effects of different concentrations and formulas of TiO2 spraying agent on photosynthetic pigment content, photosynthetic physiological indexes and chlorophyll fluorescence parameters of upper tobacco leaves at maturity were studied.
Result TiO2 spraying agents retarded the degradation rates of chlorophyll and carotenoid of upper tobacco leaves. The spraying agents reduced photosynthetic rate, stomatal conductance and transpiration rate of upper tobacco leaves, increased the intercellular CO2 concentration in upper tobacco leaves, but leaf temperature was unaffected. Photosynthesis and chlorophyll fluorescence parameters of upper tobacco leaves were significantly affected by TiO2 spraying agents. Compared with the spraying water control, the spraying agents increased Fv/Fm, Fv/Fo and qP , and decreased Fo and NPQ. The absorption efficiency of light intensity of tobacco leaves sprayed titanium dioxide or titanium dioxide composite graphene was the best at the concentration of 0.45 g·L–1.
Conclusion Tobacco leaves can absorb ultraviolet (UV) to a certain extent, and the efficiency of spraying titanium dioxide composite graphene was better. There was a threshold of spraying agent concentration for light absorption efficiency.