Leaves, in which stomata are present on the upper epidermis are called epistomatic leaves. In Nympheae, Nelumbo, Victoria, epistomatic leaves are present.
The function of the stomata is to allow water vapor and gases to pass in and out of the leaf. The stomata are also responsible for the process of transpiration, the rate at which a plant loses water. Air enters the plant through the stomata. The air contains carbon dioxide which is used in the photosynthesis process. Then the transpiration and photosynthesis are the main functions of leaves.
Hydrophytes, in which root system is rooted in the soil and their leaves float on the surface of water. In these leaves, stomata are present on the upper epidermis or surface. Such leaves are called Epistomatous leaves. Eg:Nelumbo, Nympheae.
So, the correct option is ‘Upper surface’.
In the veins of leaves, the phloem is situated towards
In the vascular bundles of leaves, xylem is situated towards the adaxial or upper epidermis side and phloem is situated towards the abaxial or lower epidermis side.