<Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2009) (Learn how and when to remove this template message) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This article needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (February 2009) (Learn how and when to remove this template message) </Td> </Tr> <P> The epidermal cells of onions provide a protective layer against viruses and fungi that may harm the sensitive tissues . Because of their simple structure and transparency they are often used to introduce students to plant anatomy or to demonstrate plasmolysis . The clear epidermal cells exist in a single layer and do not contain chloroplasts, because the onion fruiting body (bulb) is used for storing energy, not photosynthesis . Each plant cell has a cell wall, cell membrane, cytoplasm, nucleus, and a large vacuole . The nucleus is present at the periphery of the cytoplasm . The vacuole is prominent and present at the center of the cell, surrounded by cytoplasm . </P>

What type of cell did the onion cell represent