The axillary bud (or lateral bud) is an

embryonic Embryonic may refer to: *Of or relating to an embryo * ''Embryonic'' (album), a 2009 studio album by the Flaming Lips *''Embryonics ''Embryonics'' is a double-CD compilation of tracks by the Australian progressive metal band, Alchemist. It w ...

or organogenic

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 sp ...

located in the axil 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, ste ...

. Each

bud In botany, a bud is an undeveloped or embryonic shoot and normally occurs in the axil of a leaf or at the tip of a stem. Once formed, a bud may remain for some time in a dormant condition, or it may form a shoot immediately. Buds may be spec ...

has the potential to form shoots, and may be specialized in producing either vegetative shoots (stems and branches) or reproductive shoots (

flower 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 mechani ...

s). Once formed, a bud may remain dormant for some time, or it may form a shoot immediately.

Overview

An axillary bud is an embryonic or organogenic

which lies dormant at the junction of the stem and petiole of a

plant Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclu ...

. It arises exogenously from outer layer of

cortex Cortex or cortical may refer to: Biology * Cortex (anatomy), the outermost layer of an organ ** Cerebral cortex, the outer layer of the vertebrate cerebrum, part of which is the ''forebrain'' *** Motor cortex, the regions of the cerebral cortex i ...

of the stem. Axillary buds do not become actively growing shoots on plants with strong apical dominance (the tendency to grow just the terminal bud on the main stem). Apical dominance occurs because the shoot

apical meristem The meristem is a type of tissue found in plants. It consists of undifferentiated cells (meristematic cells) capable of cell division. Cells in the meristem can develop into all the other tissues and organs that occur in plants. These cells conti ...

produces auxin which prevents axillary buds from growing. The axillary buds begin developing when they are exposed to less auxin, for example if the plant naturally has weak apical dominance, if apical dominance is broken by removing the terminal bud, or if the terminal bud has grown far enough away for the auxin to have less of an effect. Searsia angustifolia (Rhus angustifolia) axillary buds 5540

Searsia angustifolia (Rhus angustifolia) axillary buds 5540

An example of axillary buds are the eyes of the potato. Axillary-buds

Effects of auxin

As the apical meristem grows and forms leaves, it leaves behind a region of meristematic cells at the node between the stem and the leaf. These axillary buds are usually dormant, inhibited by auxin produced by the apical meristem, which is known as apical dominance. If the apical meristem is removed, or has grown a sufficient distance away from an axillary bud, the axillary bud may become activated (or more appropriately freed from

hormone A hormone (from the Greek participle , "setting in motion") is a class of signaling molecules in multicellular organisms that are sent to distant organs by complex biological processes to regulate physiology and behavior. Hormones are require ...

inhibition). Like the apical meristem, axillary buds can develop into a stem or flower.

Diseases that affect axillary buds

Certain

plant diseases Plant pathology (also phytopathology) is the scientific study of diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomy ...

- notably

phytoplasma Phytoplasmas are obligate intracellular parasites of plant phloem tissue and of the insect vectors that are involved in their plant-to-plant transmission. Phytoplasmas were discovered in 1967 by Japanese scientists who termed them mycoplasma-lik ...

s - can cause the proliferation of axillary buds, and cause plants to become bushy in appearance.

References

Plant morphology {{Botany-stub