The effects of H2O2 on the structure and activity of rubisco in rice variety and its chlorophyll b less mutant

Abstract

Our previous study showed that the decline of Rubisco abundance and activity was faster than that of electronic transfer rate on photosynthetic membrane. It was due to oxidative stress in photosynthetic cell. H2O2 is the secondary substance produced by photosynthesis energy dissipation. In this paper the structure and inactivation changes of Rubisco in rice variety and its chlorophyll b less mutant under oxidative stress were investigated by means of biological spectroscopy as well as physiological measurement. With different concentrations of H2O2 treatment, the inactivation and structure changes of wild type Rubisco revealed two stages, which were little affected when H2O2 concentration in rice leaves was less than 20mM. However when H2O2 concentration in rice leaves was more than 20mM, the tertiary and secondary structure of Rubisco were greatly affected and carboxylase activity decreased significantly. Rubisco of chlorophyll b less rice mutant showed the same tendency as wild type but it was more sensitive to H2O2 stress (structure and activity of which was greatly affected by only 10mM H2O2). The difference between two types maybe result from different modification of Rubisco during leaf development.