Mechanism of Nano-anatase TiO₂ on Promoting Photosynthetic Carbon Reaction of Spinach: Inducing Complex of Rubisco-Rubisco Activase

Abstract

Having a photocatalyzed characteristic, our previous research had proved that nano-anatase TiO2 is closely related to the photosynthesis of spinach. It could not only improve the light absorbance and the transformation from light energy to electron energy and to active chemical energy but also promote carbon dioxide (CO2) assimilation of spinach. However, the mechanism of carbon reaction promoted by nano-anatase TiO2 remains largely unclear. By electrophoresis and Western blot methods, the results of the experiments proved that Rubisco from the nano-anatase TiO2-treated spinach during the extraction procedure of Rubisco was found to consist of Rubisco and a heavier molecular-mass protein (about 1,200 kDa) comprising both Rubisco and Rubisco activase. The Rubisco carboxylase activity was 2.67 times that of Rubisco from the control and it could hydrolyze ATP in the same manner as Rubisco activase. The total sulfhydryl groups and available sulfhydryl groups of the Rubisco were 32 -SH and 21 -SH per mole of enzyme more than those of the Rubisco purified from the control, respectively. The circular dichroism spectra showed that the secondary structure of Rubisco from the nano-anatase TiO2-treated spinach was very different from Rubisco of the control. It suggested that the mechanism of nano-anatase TiO2 activating Rubisco of spinach was that the complex of Rubsico and Rubisco activase was induced in spinach, which promoted Rubsico carboxylation and increased the rate of photosynthetic carbon reaction.

Fe2O3 magnetic nanoparticles to enhance S. lycopersicum (tomato) plant growth and their biomineralization

“…It indicates that Fe 2 O 3 NPs in the range of 50-200 mgL -1 could be used in agricultural practices. A similar observation was made in the case of TiO 2 and Fe 2 O 3 NPs by treating spinach and pumpkin plant, respectively (Gao et al 2008;Zhu et al 2008). The biocompatible magnetic fluid NPs have also shown to induce good germination in maize (Racuciu et al 2009).…”

Influence of Bulk and Nanoparticles Titanium Foliar Application on some Agronomic Traits, Seed Gluten and Starch Contents of Wheat Subjected to Water Deficit Stress

“…An increase of gluten and starch in treated plants with titanium may be due to the positive correlation between titanium application and photosynthesis rate so that titanium application improved CO 2 metabolism in spinach. This increase in photosynthesis was attributed to an improvement of rubisco activity (Gao et al, 2006). biomass.…”

Impact of biosynthesized silver nanoparticles on protein and carbohydrate contents in seeds of Pisum sativum L.

“…Studies with TiO 2 nanoparticles in Spinacia oleracea detected positive interactions with photosystems, especially an enhanced Rubisco activity (Zheng et al 2005, Gao et al 2006, while a Rubisco-limiting effect was detected with increasing concentrations of ferro fluid aqueous solution. This solution affected the growth of Zea mays at different photosynthetic stages by employing magnetic effect on the structures of enzymes (Racuciu and Creanga 2007).…”