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.
The epidermis of petals also form a variation of trichomes called conical cells. These cells all develop from the pavement cells, which make up the majority of the plants surface cells. In short, cellular differentiation of the epidermal cells is controlled by two major factors: genetics and environmental conditions.tomata are holes in the plant epidermis that are surrounded by two guard cells, which control the opening and closing of the aperture. These guard cells are in turn surrounded by subsidiary cells which provide a supporting role for the guard cells. Stomata begin as stomatal meristemoids.