Visualization of 14C-labeled Gas Fixation in a Plant

Abstract

AbstractWe targeted not only the elements we can supply to the nutrient solution but also carbon dioxide gas to visualize the fixation process and the movement of assimilated carbon in a plant. This is another highlight of our study using real-time RI imaging systems (RRIS). The interesting result was that the route of assimilated carbon was different depending on where the fixation took place. In Arabidopsis, most of the metabolites after photosynthesis were transferred to the tip of the main internode and roots when 14CO2 gas was fixed and photosynthates were produced at rosette leaves, whereas most of the metabolites moved to the tip of the branch internode and hardly moved down to the roots when 14CO2 gas was supplied to the aboveground parts of the plant other than rosette leaves. Interestingly, it was possible to visualize and trace which tissue performed the fixation of 14CO2 gas, i.e., carbon could be traced from the fixation site in tissue to tissue formation. However, especially in the case of 14C imaging, image analysis should be carefully performed because of the self-absorption of the β-rays in tissue. To image 14CO2 gas fixation in larger samples, approximately 50 cm in height, a plastic scintillator was introduced, and the assimilation process of the gas was visualized for rice and maize.