The functions of storage parenchyma are:They help to store different substances such as water, proteins, starch, etc. They serve as food and water reservoirs. They store protein as a good source of nitrogen for plants.In succulent plants, storage parenchyma cells are specialized for the storage of water. For example, in Cactaceae, agave, etc.In underground stems such as potato tubers, they can initiate shoot growth and provide moisture for the initial growth of the plants.