XVI International Botanical Congess

The rising CO2 concentration in the atmosphere can influence world ecosystems by direct effects on plant life, which have relation to the structure and function of chloroplasts. Wheat (C3), maize (C4), Cycas panzhihuaensis (C3, sun-type), and C. multipinnata (shade-type) were chosen to make a response to doubled CO2 concentration using 77K fluorescence emission spectroscopy, electron microscopy, etc. The result showed that at the doubled CO2 concentration stacking degree of grana thylakoids, well-keeping conformation of photosynthetic membrane system, and the F684/F735 (PS II/PS I) ration in the chloroplasts were decreased from Cycas multipinnata, then wheat, C. panzhihuaensis to maize, but converse in their accumulation of start grains, and chl a/b ratio. The present study indicated that under the elevated CO2 concentration C3 plant C. multipinnata and wheat grew very well, then C. panzhihuaensis, but C4 plant maize worse. It is noticed that environmental change had little effect on life of C3 plants esp. ancient cycads.