This proposal requests funds to purchase a transmission electon microscope (TEM). The replacement TEM will include features such as an expanded range of magnification, a tilt goniometer that will allow stereo photography, a high capacity camera, and a video camera system that displays and/or stores the projected electron image. The TEM will be used for studies on the development and structure of leaves of selected C3 and C4 plants, studies on the green alga Coleochaete as a source of clues to the early evolutionary history of land plants, studies on leaf morphogenesis to determine the attainment of photosynthetic competency, studies to elucidate the cytological and histological processes of wound healing in response to bruising in potatoes, and studies on healthy and diseased marigold cultivars infected with Pseudomas syringae.