Parenchyma cells are the primary tissue of higher plants. They are composed of thin-walled cells and forming the greater part of leaves, roots, the pulp of fruit, and the pith of stems. Parenchyma cells are the most abundant cell type. They are relatively not specialized. The thin-walled parenchyma cells have distinct intercellular spaces and large vacuoles. The main function of the parenchyma cells of roots and stems is the storage of food and water.