Bulb

Inbotany,abulbis a shortunderground stemwith fleshyleavesor leaf bases^[1]that function asfood storage organsduringdormancy.Ingardening,plants with other kinds of storage organ are also calledornamental bulbous plantsor justbulbs.

Description

The bulb's leaf bases, also known asscales,generally do not support leaves, but contain food reserves to enable the plant to survive adverse conditions. At the center of the bulb is a vegetative growing point or an unexpanded flowering shoot. The base is formed by a reducedstem,and plant growth occurs from this basal plate.Rootsemerge from the underside of the base, and new stems and leaves from the upper side.Tunicatebulbs have dry, membranous outer scales that protect the continuous lamina of fleshy scales.^[2]Species in the generaAllium,Hippeastrum,Narcissus,andTulipaall have tunicate bulbs. Non-tunicate bulbs, such asLiliumandFritillariaspecies, lack the protective tunic and have looser scales.^[3]

Bulbous plant species cycle through vegetative and reproductive growth stages; the bulb grows to flowering size during the vegetative stage and the plant flowers during the reproductive stage. Certain environmental conditions are needed to trigger the transition from one stage to the next, such as the shift from a cold winter to spring.^[2]Once the flowering period is over, the plant enters a foliage period of about six weeks during which time the plant absorbs nutrients from the soil and energy from the sun for setting flowers for the next year. Bulbs dug up before the foliage period is completed will not bloom the following year but then should flower normally in subsequent years.^[4]

Plants that form bulbs

Plants that form undergroundstorage organs,including bulbs as well astubersandcorms,are calledgeophytes.Someepiphytic orchids(familyOrchidaceae) form above-ground storage organs calledpseudobulbs,that superficially resemble bulbs.^{[citation needed]}

Nearly all plants that form true bulbs aremonocotyledons,and include:^[4]

Amaryllis,Crinum,Hippeastrum,Narcissus,and several other members of the amaryllis familyAmaryllidaceae.This includesonion,garlic,and otheralliums,members of the Amaryllid subfamilyAllioideae.
Lily,tulip,and many other members of the lily familyLiliaceae.
Two groups ofIrisspecies, familyIridaceae:subgenusXiphium(the "Dutch" irises) and subgenusHermodactyloides(the miniature "rock garden" irises).

The onlyeudicotplants that produce true bulbs are just a few species in the genusOxalis,such asOxalis latifolia.^[5]^[6]

Bulbil

Abulbilis a small bulb, and may also be called abulblet,bulbet,orbulbel.^[7]

Small bulbs can develop or propagate a large bulb. If one or several moderate-sized bulbs form to replace the original bulb, they are calledrenewal bulbs.^[7]Increase bulbsare small bulbs that develop either on each of the leaves inside a bulb, or else on the end of small underground stems connected to the original bulb.^[7]

Some lilies, such as the tiger lilyLilium lancifolium,form small bulbs, called bulbils, in their leafaxils.Several members of the onion family, Alliaceae, includingAllium sativum(garlic), form bulbils in their flower heads, sometimes as the flowers fade, or even instead of the flowers (which is a form ofapomixis). The so-calledtree onion(Allium×proliferum) forms small onions which are large enough forpickling.^{[citation needed]}

Some ferns, such asthe hen-and-chicken fern,produce new plants at the tips of the fronds' pinnae that are sometimes referred to as bulbils.

Bulbils form in the leaf axils ofLilium lancifolium
Wild garlic (Allium vineale) bulbils sprouting
"Tree onions"form clusters of small bulbs instead of flowers

References

^Bell, A.D. 1997.Plant form: an illustrated guide to flowering plant morphology.Oxford University Press, Oxford, U.K.
^^a ^bMishra, S.R. (2005).Plant Reproduction.Discovery Publishing House. pp. 120–125.ISBN 978-81-7141-955-5.
^Ellis, Barbara W. (2001).Bulbs.Houghton Mifflin Harcourt.p.3.ISBN 978-0-618-06890-6.
^^a ^b"Advances in bulb crops"(PDF).Department of Agriculture, Andhra University, Visakhapatnam, Andhra Pradesh, India.
^Hartmann, Hudson Thomas; Dale E. Kester (2002).Hartmann and Kester's Plant Propagation: Principles and Practices(7 ed.).Prentice Hall.p.561.ISBN 978-0-13-679235-2.
^Oberlander, K. C.; Emshwiller, E.; Bellstedt, D.U. & Dreyer, L.L. (2009). "A model of bulb evolution in the eudicot genusOxalis(Oxalidaceae) ".Molecular Phylogenetics & Evolution.51(1): 54–63.doi:10.1016/j.ympev.2008.11.022.PMID 19070669.
^^a ^b ^cBell, A.D. (1997).Plant form: an illustrated guide to flowering plant morphology.Oxford, U.K.:Oxford University Press.

Bulb

Description

Plants that form bulbs

Bulbil

See also

References

Further reading