As the word "deposito" has both real and symbolic meaning, the symbolic use of "deposito" = storehouse (which is also frequently used symbolically) should, if possible, be retained.

or stores of reserves if you prefer

The plants are leafy and nutritious, with dense basal leaves. Russian wildrye is adapted for either fall or early spring grazing and under some circumstances for spring-fall use. Grazing Russian wildrye when plants are rapidly replenishing reserves or before maturity reduces subsequent new growth and carbohydrate reserve stores in the autumn. Seedling vigor is low, but once established, plants are deep- rooted, drought resistant and salt tolerant. (1st ref)

Plants are composed of a number of tiny structures to which the name of cells has been given. These cells are wonderful little laboratories where are elaborated starch, sugar, and carbonaceous, or popularly speaking, fatty substances of all kinds. These fatty substances are found in the cells composing the outer covering of fruits, and still more often in the cells of seeds where they are kept by the plant as a reserve store of food for its offspring. But it is not only to the plant that these fatty substances are of use, they are also of great service to man. (2nd ref)

The role of the shoot is to create Sugars from sunlight, Water, and CO2 harvested from the air. It also harvests the majority of O2 needed by theplant for respiration. The shoot may serve as a reserve store for Water & Minerals. This may be far fetched as a general principle but the storage of Water is true for at least the cactus. The best place for storage of all nutrients may be out of all harms way in the soil, in the root. The shoot also provides the structure that supports the leaves, flowers and fruit but this will not be important here.
http://www.pruittfamily.com/paul/plants.htm