Somatic Embryogenesis in Cell Suspension Culture of Saposhnikovia divaricata A Study on the Leaf Structure of Four Reed Ecotypes Effects of Cinnamic Acid on Photosynthesis and Cell Ultrastructure ofCucumber Seedling Effects of Cinnamic Acid on Photosynthesis and Cell Ultrastructure ofCucumber Seedling Ultrastructural Study on the Degenerative Processes of Procambial Cells in Maize Leaf Blades