CT scan. A computed tomography (CT) scan is an imaging method that uses x-rays to create pictures of cross-sections of the body. How the Test is Performed. You will be asked to lie on a narrow table that slides into the center of the CT scanner. Once you are inside the scanner, the machine's x-ray beam rotates around you.
If it is a submerged leaf, no stomata will be present on either side. In botany, a stoma (also stomate; plural stomata) is a tiny opening or pore, found mostly on the under-surface (epidermis) of a plant leaf, and used for gas exchange.The pore is formed by a pair of specialized parenchyma cells known as guard cells which are responsible for regulating the size of the opening. years ago. Dicotyledons usually have more stomata on the lower epidermis than the upper epidermis. As these leaves are held horizontally, upper epidermis is directly illuminated. Locating fewer stomata on the upper epidermis can then prevent excess water loss.
Two more specialized cell types are also found in the epidermis: guard cells and trichomes. Guard cells are kidney-shaped cells that are filled with chloroplasts. They always occur in pairs and form a small pore between them. The pair of guard cells and their pore is called a stomate and functions in gas exchange.