|MadSci Network: Botany|
Some plants, such as oriental poppy, can be propagated from pieces of their roots, termed root cuttings. However, pieces of roots from true bulbs could not be used as root cuttings. A true bulb is not a modified root. It consists of a short stem termed the basal plate and fleshy leaves, termed scales, that are modified for storage. Many true bulbs, such as daffodils, split or form offsets or bulblets as a method of clonal reproduction. Other true bulbs, such as tulip, disintegrate each year so only offsets are left for the next year. Some true bulbs, such as some lilies, also form very tiny bulbs, called bulbils, on their stems. Some onions and garlic plants produce bulbils on their flowering stalks. Cutting or cutting apart some true bulbs, such as hyacinth, can stimulate formation of bulblets on the cut surfaces. Flowering plants with true bulbs can also reproduce via seeds. Gardeners use the term bulb in a wider sense to mean any undergound storage organ used for propagation. In that sense a "bulb" can be any of the following: 1. a true bulb such as tulip, onion, daffodil, lily or amaryllis 2. a horizontal underground stem (rhizome) such as iris or lily of the valley 3. an enlarged underground stem (tuber) such as potato or tuberous begonia 4. a compressed stem (corm) such as crocus or gladiolus 5. a tuberous root such as sweet potato or dahlia All these "bulbs" or geophytes can also form offsets or multiply their underground storage organs as a method of reproduction. This is a good season to study bulbs because of the wide availability of Christmas amaryllis (Hippeastrum). They are an excellent bulb for classroom forcing. Your public library might have one of more of the dozens of gardening books devoted to gardening bulbs. References Root cuttings Root cuttings of oriental poppy Propagating lilies from bulbils Onion bulbils Hyacinth propagation Geophytes Specialized vegetative structures Hershey, D.R. 2002. Hippeastrum is hardly a humdrum classroom plant. Science Activities 39(3):19-26.
Try the links in the MadSci Library for more information on Botany.