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botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek w ...
, a bud is an undeveloped or embryonic
shoot In botany, a plant shoot consists of any plant stem together with its appendages, leaves and lateral buds, flowering stems, and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the spr ...
and normally occurs in the
axil A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...
of a
leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ...
or at the tip of a
stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...
. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be specialized to develop
flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechanism ...
or short shoots or may have the potential for general shoot development. The term bud is also used in
zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and ...
, where it refers to an outgrowth from the body which can develop into a new individual.


Overview

The buds of many
woody plant A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposite to herbaceous plants that die back to the ground until ...
s, especially in temperate or cold climates, are protected by a covering of modified leaves called ''scales'' which tightly enclose the more delicate parts of the bud. Many bud scales are covered by a gummy substance which serves as added protection. When the bud develops, the scales may enlarge somewhat but usually just drop off, leaving a series of horizontally-elongated
scar A scar (or scar tissue) is an area of fibrous tissue that replaces normal skin after an injury. Scars result from the biological process of wound repair in the skin, as well as in other organs, and tissues of the body. Thus, scarring is a nat ...
s on the surface of the growing stem. By means of these scars one can determine the age of any young branch, since each year's growth ends in the formation of a bud, the formation of which produces an additional group of bud scale scars. Continued growth of the branch causes these scars to be obliterated after a few years so that the total age of older branches cannot be determined by this means. In many plants, scales do not form over the bud, and the bud is then called a naked bud. The minute underdeveloped leaves in such buds are often excessively hairy. Naked buds are found in some shrubs, like some species of the
Sumac Sumac ( or ), also spelled sumach, is any of about 35 species of flowering plants in the genus ''Rhus'' and related genera in the cashew family ( Anacardiaceae). Sumacs grow in subtropical and temperate regions throughout the world, including E ...
and
Viburnum ''Viburnum'' is a genus of about 150–175 species of flowering plants in the moschatel family Adoxaceae. Its current classification is based on molecular phylogeny. It was previously included in the honeysuckle family Caprifoliaceae. The me ...
s (''Viburnum alnifolium'' and ''V. lantana'') and in
herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition o ...
plants. In many of the latter, buds are even more reduced, often consisting of undifferentiated masses of cells in the axils of leaves. A terminal bud occurs on the end of a stem and lateral buds are found on the side. A head of
cabbage Cabbage, comprising several cultivars of ''Brassica oleracea'', is a leafy green, red (purple), or white (pale green) biennial plant grown as an annual vegetable crop for its dense-leaved heads. It is descended from the wild cabbage ( ''B.&n ...
(see
Brassica ''Brassica'' () is a genus of plants in the cabbage and mustard family (Brassicaceae). The members of the genus are informally known as cruciferous vegetables, cabbages, or mustard plants. Crops from this genus are sometimes called ''cole c ...
) is an exceptionally large terminal bud, while
Brussels sprout The Brussels sprout is a member of the Gemmifera cultivar group of cabbages (''Brassica oleracea''), grown for its edible buds. The leaf vegetables are typically 1.5–4.0 cm (0.6–1.6 in) in diameter and resemble miniature cabbages ...
s are large lateral buds. Since buds are formed in the axils of leaves, their distribution on the stem is the same as that of leaves. There are alternate, opposite, and whorled buds, as well as the terminal bud at the tip of the stem. In many plants buds appear in unexpected places: these are known as adventitious buds. Often it is possible to find a bud in a remarkable series of gradations of bud scales. In the buckeye, for example, one may see a complete gradation from the small brown outer scale through larger scales which on unfolding become somewhat green to the inner scales of the bud, which are remarkably leaf-like. Such a series suggests that the scales of the bud are in truth leaves, modified to protect the more delicate parts of the plant during unfavorable periods.


Types of buds

Buds are often useful in the identification of plants, especially for woody plants in winter when leaves have fallen. Buds may be classified and described according to different criteria: location, status, morphology, and function. Botanists commonly use the following terms: *for location: **, when located at the tip of a stem (apical is equivalent but rather reserved for the one at the top of the plant); ** axillary, when located in the axil of a leaf (lateral is the equivalent but some adventitious buds may be lateral too); **
adventitious Important structures in plant development are buds, shoots, roots, leaves, and flowers; plants produce these tissues and structures throughout their life from meristems located at the tips of organs, or between mature tissues. Thus, a living plant ...
, when occurring elsewhere, for example on trunk or on roots (some adventitious buds may be former axillary ones reduced and hidden under the bark, other adventitious buds are completely new formed ones). *for status: **accessory, for secondary buds formed besides a principal bud (axillary or terminal); **resting, for buds that form at the end of a growth season, which will lie dormant until onset of the next growth season; **dormant or latent, for buds whose growth has been delayed for a rather long time. The term is usable as a synonym of ''resting'', but is better employed for buds waiting undeveloped for years, for example epicormic buds; **pseudoterminal, for an axillary bud taking over the function of a terminal bud (characteristic of species whose growth is
sympodial Sympodial growth is a bifurcating branching pattern where one branch develops more strongly than the other, resulting in the stronger branches forming the primary shoot and the weaker branches appearing laterally. A sympodium, also referred to a ...
: terminal bud dies and is replaced by the closer axillary bud, for examples
beech Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engle ...
,
persimmon The persimmon is the edible fruit of a number of species of trees in the genus ''Diospyros''. The most widely cultivated of these is the Oriental persimmon, '' Diospyros kaki'' ''Diospyros'' is in the family Ebenaceae, and a number of non-pe ...
, ''
Platanus ''Platanus'' is a genus consisting of a small number of tree species native to the Northern Hemisphere. They are the sole living members of the family Platanaceae. All mature members of ''Platanus'' are tall, reaching in height. All except f ...
'' have sympodial growth). *for morphology: **scaly or covered (perulate), when scales, also referred to as a perule (lat. perula, perulaei) (which are in fact transformed and reduced leaves) cover and protect the embryonic parts; **naked, when not covered by scales; **hairy, when also protected by hairs (it may apply either to scaly or to naked buds). *for function: **vegetative, if only containing vegetative pieces: embryonic shoot with leaves (a leaf bud is the same); **reproductive, if containing embryonic flower(s) (a flower bud is the same); **mixed, if containing both embryonic leaves and flowers.


Image gallery

File:Alnus glutinosa bud 2.jpg, ''
Alnus glutinosa ''Alnus glutinosa'', the common alder, black alder, European alder, European black alder, or just alder, is a species of tree in the family Betulaceae, native to most of Europe, southwest Asia and northern Africa. It thrives in wet locations wh ...
'' bud File:Tilia platyphallos bud.jpg, ''
Tilia ''Tilia'' is a genus of about 30 species of trees or bushes, native throughout most of the temperate Northern Hemisphere. The tree is known as linden for the European species, and basswood for North American species. In Britain and Ireland the ...
'' bud File:Buds of Fraxinus excelsior 03.jpg, Black buds of a European ash, '' Fraxinus excelsior'' File:Bud1web.jpg, An opening
inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...
bud at left, that will develop like the one to its right File:Flower bud of Sunflower - Helianthus.JPG, Inflorescence bud of a
sunflower The common sunflower (''Helianthus annuus'') is a large annual forb of the genus ''Helianthus'' grown as a crop for its edible oily seeds. Apart from cooking oil production, it is also used as livestock forage (as a meal or a silage plant), as ...
File:Quince Blossom with removed watermark.jpg, A
quince The quince (; ''Cydonia oblonga'') is the sole member of the genus ''Cydonia'' in the Malinae subtribe (which also contains apples and pears, among other fruits) of the Rosaceae family. It is a deciduous tree that bears hard, aromatic bright ...
's flower bud with spirally folded petals File:Nelumbo nucifera, also known as Indian lotus in bud stage (Image 7 of 7).jpg, Opening ''
Nelumbo ''Nelumbo'' is a genus of aquatic plants with large, showy flowers. Members are commonly called lotus, though the name is also applied to various other plants and plant groups, including the unrelated genus '' Lotus''. Members outwardly resemb ...
'' flower bud File:Coreopsis tinctoria cultivar Uptick Cream and Red 8.JPG, Opening ''
Coreopsis tinctoria Plains coreopsis, garden tickseed, golden tickseed, or calliopsis, ''Coreopsis tinctoria'', is an annual forb. The plant is common in Canada (from Quebec to British Columbia), northeast Mexico (Coahuila, Nuevo León, Tamaulipas), and much of t ...
'' flower buds File:Vitis vinifera - bud0.jpg, ''
Vitis vinifera ''Vitis vinifera'', the common grape vine, is a species of flowering plant, native to the Mediterranean region, Central Europe, and southwestern Asia, from Morocco and Portugal north to southern Germany and east to northern Iran. There are curr ...
'' flower buds File:烏材(軟毛柿)Diospyros eriantha 20210331093242 04.jpg, '' Diospyros eriantha'' bud


References

{{Authority control Plant physiology Plant morphology