Bulb

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Shallot bulbs Shallots-Whole.jpg
Shallot bulbs
Hippeastrum (amaryllis) bulb Amaryllisbulb.jpg
Hippeastrum (amaryllis) bulb

In botany, a bulb is a short underground stem with fleshy leaves or leaf bases [1] that function as food storage organs during dormancy. In gardening, plants with other kinds of storage organ are also called ornamental bulbous plants or just bulbs.

Contents

Description

Longitudinal section through bulb Red onion cut labelled.svg
Longitudinal section through bulb
Cross section of onion bulb Red onion cross section 04.jpg
Cross section of onion bulb

The bulb's leaf bases, also known as scales, 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 reduced stem, and plant growth occurs from this basal plate. Roots emerge from the underside of the base, and new stems and leaves from the upper side. Tunicate bulbs have dry, membranous outer scales that protect the continuous lamina of fleshy scales. [2] Species in the genera Allium , Hippeastrum , Narcissus , and Tulipa all have tunicate bulbs. Non-tunicate bulbs, such as Lilium and Fritillaria species, 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 underground storage organs, including bulbs as well as tubers and corms, are called geophytes. Some epiphytic orchids (family Orchidaceae) form above-ground storage organs called pseudobulbs , that superficially resemble bulbs.[ citation needed ]

Nearly all plants that form true bulbs are monocotyledons, and include: [4]

The only eudicot plants that produce true bulbs are just a few species in the genus Oxalis , such as Oxalis latifolia . [5] [6]

Bulbil

A bulbil is a small bulb, and may also be called a bulblet, bulbet, or bulbel. [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 called renewal bulbs. [7] Increase bulbs are 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 lily Lilium lancifolium , form small bulbs, called bulbils, in their leaf axils. Several members of the onion family, Alliaceae, including Allium sativum (garlic), form bulbils in their flower heads, sometimes as the flowers fade, or even instead of the flowers (which is a form of apomixis). The so-called tree onion (Allium × proliferum) forms small onions which are large enough for pickling.[ citation needed ]

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

See also

Related Research Articles

<i>Amaryllis</i> Genus of plants

Amaryllis is the only genus in the subtribe Amaryllidinae. It is a small genus of flowering bulbs, with two species. The better known of the two, Amaryllis belladonna, is a native of the Western Cape region of South Africa, particularly the rocky southwest area between the Olifants River Valley and Knysna.

<span class="mw-page-title-main">Onion</span> Bulbous vegetable grown for food

An onion, also known as the bulb onion or common onion, is a vegetable that is the most widely cultivated species of the genus Allium. The shallot is a botanical variety of the onion which was classified as a separate species until 2011. The onion's close relatives include garlic, scallion, leek, and chives.

<i>Lilium lancifolium</i> Species of lily

Lilium lancifolium is an Asian species of lily, native to China, Japan, Korea, and the Russian Far East. It is widely planted as an ornamental because of its showy orange-and-black flowers, and sporadically occurs as a garden escapee in North America, particularly the eastern United States including New England, and has made incursions into some southern states such as Georgia.

<i>Lilium</i> Genus of plants

Lilium is a genus of herbaceous flowering plants growing from bulbs, all with large and often prominent flowers. Lilies are a group of flowering plants which are important in culture and literature in much of the world. Most species are native to the Northern Hemisphere and their range is temperate climates and extends into the subtropics. Many other plants have "lily" in their common names, but do not belong to the same genus and are therefore not true lilies. True lilies are known to be highly toxic to cats.

<i>Hippeastrum</i> Genus of flowering plants in the family Amaryllidaceae

Hippeastrum is a genus of about 90 species, and over 600 hybrids and cultivars, of perennial, herbaceous and bulbous plants, native to tropical and subtropical regions of the Americas, from Mexico south to Argentina and on some islands in the Caribbean. The majority have large, fleshy bulbs—usually about the size of a softball—and tall, broad, strap-like leaves that are (generally) evergreen, and large red or purple flowers. Numerous colors and cultivars have been created over the past hundred years.

<i>Allium ursinum</i> Species of flowering plant in the family Amaryllidaceae

Allium ursinum, known as wild garlic, ramsons, cowleekes, cows's leek, cowleek, buckrams, broad-leaved garlic, wood garlic, bear leek, Eurasian wild garlic or bear's garlic, is a bulbous perennial flowering plant in the amaryllis family Amaryllidaceae. It is native to Europe and Asia, where it grows in moist woodland. It is a wild relative of onion and garlic, all belonging to the same genus, Allium. There are two recognized subspecies: A. ursinum subsp. ursinum and A. ursinum subsp. ucrainicum.

<span class="mw-page-title-main">Elephant garlic</span> Subspecies of flowering plant

Elephant garlic is a plant belonging to the onion genus. It has a tall, solid, flowering stalk, flat leaves. The flavor is milder than garlic and can be eaten raw in salads, roasted, or sauteed, but is generally not a substitute for conventional garlic in cooking. It is sometimes confused with solo garlic.

<span class="mw-page-title-main">Tree onion</span> Species of flowering plant

The tree onion is a perennial plant similar to the common onion (A. cepa), but with a cluster of bulblets where a normal onion would have flowers. Tree onions are also known as topsetting onions, walking onions, or Egyptian onions. Genomic evidence has conclusively shown that they are a diploid hybrid of the shallot and the Welsh onion (A. fistulosum). However, some sources may still treat the tree onion as A. cepa var. proliferum or A. cepa Proliferum Group.

<i>Allium vineale</i> Species of flowering plant

Allium vineale is a perennial, bulb-forming species of wild onion, native to Europe, northwestern Africa and the Middle East. The species was introduced in Australia and North America, where it has become an Invasive species.

A storage organ is a part of a plant specifically modified for storage of energy (generally in the form of carbohydrates) or water. Storage organs often grow underground, where they are better protected from attack by herbivores. Plants that have an underground storage organ are called geophytes in the Raunkiær plant life-form classification system. Storage organs often, but not always, act as perennating organs which enable plants to survive adverse conditions.

<i>Allium canadense</i> Species of flowering plant

Allium canadense, the Canada onion, Canadian garlic, wild garlic, meadow garlic and wild onion is a perennial plant native to eastern North America from Texas to Florida to New Brunswick to Montana. The species is also cultivated in other regions as an ornamental and as a garden culinary herb. The plant is also reportedly naturalized in Cuba.

<i>Allium scorodoprasum</i> Species of flowering plant

The sand leek, also known as rocambole and Korean pickled-peel garlic, is a Eurasian species of wild onion with a native range extending across much of Europe, Middle East, and Korea. The species should not be confused with rocambole garlic, which is A. sativum var. ophioscorodon.

<i>Allium sphaerocephalon</i> Species of flowering plant

Allium sphaerocephalon is a plant species in the Amaryllis family known as round-headed leek, round-headed garlic, ball-head onion, and other variations on these names. Drumstick allium is another common name applied to this species. Some publications use the alternate spelling Allium sphaerocephalum. It is a bulbous herbaceous perennial plant.

<span class="mw-page-title-main">Bulbil</span> Small young plant that grows from the parent plants stem

A bulbil is a small, young plant that is reproduced vegetatively from axillary buds on the parent plant's stem or in place of a flower on an inflorescence. These young plants are clones of the parent plant that produced them—they have identical genetic material. The formation of bulbils is a form of asexual reproduction, as they can eventually go on to form new stand-alone plants.

<span class="mw-page-title-main">Ornamental bulbous plant</span> Herbaceous perennials with underground storage parts grown for ornamental purposes

Ornamental bulbous plants, often called ornamental bulbs or just bulbs in gardening and horticulture, are herbaceous perennials grown for ornamental purposes, which have underground or near ground storage organs. Botanists distinguish between true bulbs, corms, rhizomes, stem tubers and tuberous roots, any of which may be termed "bulbs" in horticulture. Bulb species usually lose their upper parts during adverse conditions such as summer drought and heat or winter cold. The bulb's storage organs contain moisture and nutrients that are used to survive these adverse conditions in a dormant state. When conditions become favourable the reserves sustain a new growth cycle. In addition, bulbs permit vegetative or asexual multiplication in these species. Ornamental bulbs are used in parks and gardens and as cut flowers.

<i>Allium paradoxum</i> Species of flowering plant in the family Amaryllidaceae

Allium paradoxum, the few-flowered garlic or few-flowered leek, is an Asian species of wild onion in the Amaryllis family. It is native to mountainous regions of Iran, Caucasus, and Turkmenistan and invasive in Europe.

Allium rhynchogynum is a Chinese species of wild onion endemic to the Yunnan region in southern China. It grows at elevations of 2700–3200 m.

The Asparagales are an order of plants, and on this page the structure of the order is used according to the APG III system. The order takes its name from the family Asparagaceae and is placed in the monocots. The order is clearly circumscribed on the basis of DNA sequence analysis, but is difficult to define morphologically, since its members are structurally diverse. The APG III system is used in World Checklist of Selected Plant Families from the Royal Botanical Gardens at Kew. With this circumscription, the order consists of 14 families with approximately 1120 genera and 26000 species.

<i>Allium</i> Genus of flowering plants in the family Amaryllidaceae

Allium is a genus of monocotyledonous flowering plants with hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. It is one of about 57 genera of flowering plants with more than 500 species. It is by far the largest genus in the Amaryllidaceae, and also in the Alliaceae in classification systems in which that family is recognized as separate.

References

  1. Bell, A.D. 1997. Plant form: an illustrated guide to flowering plant morphology. Oxford University Press, Oxford, U.K.
  2. 1 2 Mishra, S.R. (2005). Plant Reproduction. Discovery Publishing House. pp. 120–125. ISBN   978-81-7141-955-5.
  3. Ellis, Barbara W. (2001). Bulbs . Houghton Mifflin Harcourt. p.  3. ISBN   978-0-618-06890-6.
  4. 1 2 "Advances in bulb crops" (PDF). Department of Agriculture, Andhra University, Visakhapatnam, Andhra Pradesh, India.
  5. 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.
  6. Oberlander, K. C.; Emshwiller, E.; Bellstedt, D.U. & Dreyer, L.L. (2009). "A model of bulb evolution in the eudicot genus Oxalis (Oxalidaceae)". Molecular Phylogenetics & Evolution. 51 (1): 54–63. doi:10.1016/j.ympev.2008.11.022. PMID   19070669.
  7. 1 2 3 Bell, A.D. (1997). Plant form: an illustrated guide to flowering plant morphology. Oxford, U.K.: Oxford University Press.

Further reading