Many plants accumulate food -- sugars, starches, and other products -- especially in fruits and seeds and in modified roots and stems.

Fruits of various types (see Chapter 9) serve as food reservoirs. Examples are Malus spp. (apples), Prunus spp. (cherries), Mangifera indica (mangos), and Cucurbita spp. (squashes), as well as the one-seeded dry fruits of the grains, such as Triticum aestivum (wheat) and Zea mays (corn).

Seeds of such plants as Pisum sativum (English pea) serve as food reservoirs.

Roots accumulate food, such as the taproot of Daucus carota (carrots), Pastinaca sativa (parsnips), and Beta vulgaris (beets), and the tuberous roots of Ipomoea batatas (sweet potatoes) and Manihot esculenta (cassavas). These root tubers do not have buds or "eyes", but may produce adventitious ones which become stems.

Stems may be adapted as food reservoirs, as in the following examples:

• Stem Tubers usually grow underground but have buds or "eyes" from which spring new stems, such as in Solanum tuberosum (Irish potato) or Caladium bicolor (caladium), see Caladium hortulanum .
• Corms are solid masses of stem tissue. They are actually a condensed stem with a bud on top from which the new stem grows. Gladiolus spp. (gladiolus) is an example of a corm.
  • Cormels are small corms which form around the base of a larger corm.
• Bulbs are compressed stems containing a growing point (bud) or flower bud enclosed by thick, fleshy scale leaves. Some bulbs such as Hippeastrum spp. (amaryllis) and Allium cepa (onion) are called tunicate bulbs because they are protected from drying and mechanical injury by dry and membranous outer scales called a tunic.
  • Other bulbs such as Lilium longiflorum (Easter lily) are called non-tunicate or scaly because their outer scales are succulent and separate.
• Bulblets are small bulbs growing from the main bulb, such as in Hippeastrum spp. (amaryllis).
• Bulbils grow on the stem in the axils of leaves or bracts. They may be small bulbs, as in some lilies, or leafy appendages, as in Alpinia purpurata (red ginger), Dietes iridioides (African iris), and Hemerocallis spp. (daylilies). Bulbils may be used for propagation.
• Rhizomes may also become a food reservoir and also an easy means of propagation by division into separate parts. Examples are Heliconia spp. (heliconia), Arundinaria gigantea (switch cane), and Pleopeltis polypodioides (Resurrection fern).

Source: Botany Handbook for Florida, Revised Edition, Kathleen C. Ruppert, January 1999 -- This document is copyrighted by the University of Florida, Institute of Food and Agricultural Sciences (UF/IFAS) for the people of the State of Florida. UF/IFAS retains all rights under all conventions, but permits free reproduction by all agents and offices of the Cooperative Extension Service and the people of the State of Florida. Permission is granted to others to use these materials in part or in full for educational purposes, provided that full credit is given to the UF/IFAS, citing the publication, its source, and date of publication.