[Photosynthetic characters and Bt toxin content of different transgenic Bt cottons]

The study on the photosynthetic characters and Bt toxin content of different Bt cottons (ZK, GK) and non-Bt cotton (CZ) indicated that Bt cottons GK and ZK had different total expressed amount of Bt toxin and its distribution in different tissues. The Bt cottons had obviously different chlorophyll contents, responses of photosynthetic rate to photosynthetic active radiation, and diurnal changes of photosynthetic rate and transpiration rate, but the diurnal change of leaf temperature, CO2 concentration inside leaf cells and stomatal limit values were approximately the same. There was a significant difference between two transgenic Bt cottons in the diurnal average value of CO2 concentration inside leaf cells, but the differences in other characteristics were not significant among different cottons.