Three-dimensional anatomy of mesophyll cells in rice leaf tissue by serial section light microscopy

2D sections of rice (Oryza sativa L.) mesophyll cells are complex and the cell interior contains a large volume of chloroplasts. Furthermore, the structure of chloroplasts changes in response to salt stress. In this study, we used a 3D reconstruction method based on serial section light microscopy to analyze a wide range of structures in leaf tissues and compared the intracellular structure of mesophyll cells of rice under normal and salt-treated conditions. The 3D reconstructed models revealed that mesophyll cells appeared as ellipsoid discs with several lobes around the cell periphery, with the volumes showing no significant difference between control and salt-treated plants. The chloroplast structure in the whole mesophyll cell was altered under salt stress, showing a reduced coverage area, whereas their volumes did not differ between treatments. These findings suggest that 3D reconstruction based on serial light micrographs can reveal the morphology of cells and chloroplasts in plant tissue.