In plants, a gland is defined functionally as a plant structure which secretes one or more products. This may be located on or near the plant surface and secrete externally, or be internal to the plant and secrete into a canal or reservoir. Examples include glandular hairs, nectaries, hydathodes, and the resin canals in Pinus. [1]
The salt glands of mangroves such as Acanthus , Aegiceras , Aegialitis and Avicennia are a distinctive multicellular trichome, a glandular hair found on the upper leaf surface and much more densely in the abaxial indumentum. On the upper leaf surface they are sunken in shallow pits, and on the lower surface they occur scattered among long nonglandular hairs composed of three or four cells. Development of the glands resembles that of the nonglandular hairs until the three-celled stage, when the short middle stalk cell appears. The salt gland continues to develop to produce two to four vacuolated cells at the level of the epidermis, the stalk cell with an almost completely cutinized wall, and at least eight terminal cells. The terminal cells have a thin, perforated cuticle which separates from the cell walls apically, leaving an enclosed cavity between them. The secreted salt evaporates and forms visible crystals. [2]
Cannabis plants are broadly covered with sessile glands, and other hairs throughout above-ground portions of the plant. There is a particularly high concentration of glands on the bracts of the female plant. After flower formation begins, some of the glands, especially on bracts near the flowers, develop stalks projecting them outward from the plant surface. The glands consist of a layer of disk cells, whose outer surface splits to create a large secretory cavity lined by cell wall and cuticle components. Together the disk cells and secretory cavity form a round head atop the narrow stalk. These cavities come to contain large amounts of cannabidiol in hemp-producing strains, or tetrahydrocannabinol and cannabinol in other cannabis plants. These compounds appear to be produced beginning in specialized plastids called lipoplasts. These produce spheres of oily secretions, including terpenes, which pass through the cell membrane and wall to accumulate as vesicles in the secretory cavity. Final reaction to cannabinoids appears to occur outside the disk cell cytoplasm. The glands gradually darken as they mature, with loss of cannabinoids over time (perhaps to evaporation) and eventually undergo abscission from the plant. [3]
Cannabis is a genus of flowering plants in the family Cannabaceae. The number of species within the genus is disputed. Three species may be recognized: Cannabis sativa, Cannabis indica, and Cannabis ruderalis; C. ruderalis may be included within C. sativa; all three may be treated as subspecies of a single species, C. sativa; or C. sativa may be accepted as a single undivided species. The genus is widely accepted as being indigenous to and originating from Central Asia, with some researchers also including upper South Asia in its origin.
A gland is a group of cells in an animal's body that synthesizes substances for release into the bloodstream or into cavities inside the body or its outer surface.
In biology, tissue is a cellular organizational level between cells and a complete organ. A tissue is an ensemble of similar cells and their extracellular matrix from the same origin that together carry out a specific function. Organs are then formed by the functional grouping together of multiple tissues.
Trichomes, from the Greek τρίχωμα (trichōma) meaning "hair", are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a plant is an indumentum, and the surface bearing them is said to be pubescent.
The paired submandibular glands are major salivary glands located beneath the floor of the mouth. They each weigh about 15 grams and contribute some 60–67% of unstimulated saliva secretion; on stimulation their contribution decreases in proportion as the parotid secretion rises to 50%. The average length of the normal human submandibular salivary gland is approximately 27mm, while the average width is approximately 14.3mm.
Sweat glands, also known as sudoriferous or sudoriparous glands, from Latin sudor 'sweat', are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial surface by way of a duct. There are two main types of sweat glands that differ in their structure, function, secretory product, mechanism of excretion, anatomic distribution, and distribution across species:
Roridula is a genus of evergreen, insect-trapping shrubs, with two species, of about 1⅓–2 m. It is the only genus in the family Roridulaceae. It has thin, woody, shyly branching, upright, initially brown, later grey stems, with lance- to awl-shaped leaves crowded at their tips. The star-symmetrical flowers consist from the outside in of five, green or reddish, free sepals, alternating with five white, pink or purple, free petals. Further to the middle and opposite the sepals are five stamens with the anthers initially kinked down. These suddenly flip up if the nectar-containing swelling at its base is being touched. The center of the flower is occupied by a superior ovary. The leaves and sepals carry many sticky tentacles of different sizes, that trap insects. Roridula does not break down the insect proteins, but bugs of the genus Pameridea prey on the trapped insects. These later deposit their feces on the leaves, which take up nutrients from the droppings. The species can be found in the Western Cape province of South Africa. They are commonly known as dewstick or fly bush in English and vlieëbos or vlieëbossie in Afrikaans.
Epicuticular wax is a coating of wax covering the outer surface of the plant cuticle in land plants. It may form a whitish film or bloom on leaves, fruits and other plant organs. Chemically, it consists of hydrophobic organic compounds, mainly straight-chain aliphatic hydrocarbons with or without a variety of substituted functional groups. The main functions of the epicuticular wax are to decrease surface wetting and moisture loss. Other functions include reflection of ultraviolet light, assisting in the formation of an ultrahydrophobic and self-cleaning surface and acting as an anti-climb surface.
Insect physiology includes the physiology and biochemistry of insect organ systems.
This page provides a glossary of plant morphology. Botanists and other biologists who study plant morphology use a number of different terms to classify and identify plant organs and parts that can be observed using no more than a handheld magnifying lens. This page provides help in understanding the numerous other pages describing plants by their various taxa. The accompanying page—Plant morphology—provides an overview of the science of the external form of plants. There is also an alphabetical list: Glossary of botanical terms. In contrast, this page deals with botanical terms in a systematic manner, with some illustrations, and organized by plant anatomy and function in plant physiology.
Roridula gorgonias is an evergreen, shyly branching, upright shrub of up to about 1 m (3 ft) high, from the family Roridulaceae. It has awl-shaped leaves with entire margins, crowded at the tip of the branches. These are set with tentacles that secrete a sticky, shiny resin from the thicker gland at their tips, that catch many airborne items. At the center of the shoots appear inflorescences between July to October that consist of up to twelve flowers in spikes, each on a short flower stalk, with a bract at its base. The 5-merous flower is about 2½ cm (1 in) in diameter and has pinkish purple or white petals. The plants do not digest the trapped insects, but the bug Pameridea roridulae sucks out their juices and the plant absorbs nutrients from the bug's droppings. It is therefore considered a protocarnivorous plant. It is called Gorgons dewstick, fly bush or fly catcher bush in English and vliebos, or vlieëbossie in Afrikaans.. R. gorgonias is an endemic species home to the southwest of the Western Cape province of South Africa.
This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology and List of Latin and Greek words commonly used in systematic names.
Pinguicula orchidioides is a perennial rosette-forming insectivorous herb native to Mexico and Guatemala. A species of butterwort, it forms summer rosettes of flat, succulent leaves up to 5 centimeters (4 in) long, which are covered in mucilaginous (sticky) glands that attract, trap, and digest arthropod prey. Nutrients derived from the prey are used to supplement the nutrient-poor substrate that the plant grows in. Uniquely among Pinguicula species from the Americas, p. orchidioides produces gemma-like basal buds which elongate into stolons and serve as a means of asexual reproduction. In the winter the plant forms a non-carnivorous rosette of small, fleshy leaves that conserves energy while food and moisture supplies are low. Single purple flowers appear between July and September on upright stalks up to 22 centimeters long.
Pinguicula, commonly known as the butterworts, is a genus of carnivorous flowering plants in the family Lentibulariaceae. They use sticky, glandular leaves to lure, trap, and digest insects in order to supplement the poor mineral nutrition they obtain from the environment. Of the roughly 80 currently known species, 13 are native to Europe, 9 to North America, and some to northern Asia. The largest number of species is in South and Central America.
Tetrahydrocannabinolic acid (THCA) synthase is an enzyme responsible for catalyzing the formation of THCA from cannabigerolic acid (CBGA). THCA is the direct precursor of tetrahydrocannabinol (THC), the principal psychoactive component of cannabis, which is produced from various strains of Cannabis sativa. Therefore, THCA synthase is considered to be a key enzyme controlling cannabis psychoactivity. Polymorphisms of THCA synthase result in varying levels of THC in Cannabis plants, resulting in "drug-type" and "fiber-type" C. sativa varieties.
In botany, tentacles are glandular hairs on the leaves of some species of insectivorous plants such as Drosera (sundews). Tentacles are different from organs such as the tendrils of climbing plants.
The tissues that are concerned with the secretion of gums, resins, volatile oils, nectar latex, and other substances in plants are called secretory tissues. These tissues are classified as either laticiferous tissues or glandular tissues.
Famatinanthus is a genus in the daisy family that was created in 2014 and has been reassigned to its own tribe Famatinantheae and subfamily Famatinanthoideae. It contains only one known species, F. decussatus, a small shrub of ½—1¾ m high that is an endemic of the Andes of north-western Argentina, with small, entire, oppositely set leaves and flowerheads containing about ten cream-colored, ray and disk florets, with backward coiled lobes. It is locally known as sacansa. For more than 100 years, the species was known to science only from the type collection used for the 1885 description which had assigned it to the genus Aphyllocladus.
Hypericum sechmenii is a rare flowering plant in the genus Hypericum, in the section Adenosepalum, Hypericum huber-morathii group. It is native to central Anatolia, Turkey.
Mairia crenata is a perennial herbaceous plant of mostly 2–15 cm (1–6 in) high that is assigned to the daisy family. It has a woody rootstock of up to 5 cm (2 in) long, from which brown, fleshy roots develop. The five to eighteen, hard and leathery, spoon-shaped leaves are in one to three rosettes, have a distinct main vein, blunt or pointy tip, often dark red or blackish margins with rounded teeth and a ½–2 cm (0.2–0.8 in) long stalk-like foot, often initially somewhat woolly hairy, on particularly the lower surface and the main vein, but this is easily rubbed off the shiny surfaces. Each rosette produces mostly one, sometimes up to four, mostly rusty or whitish woolly hairy, brown or dark red inflorescence stalks, usually 1½–15 cm long, each with two to eight, initially woolly, line-shaped to oval bracts, the lowest up to 3 cm (1.2 in), decreasing size further up, and carrying mostly one, rarely up to three flower heads. The flower heads have a bell-shaped involucre with about 40 bracts, sixteen to thirty three violet to white ray florets of about 1¼–1⅞ cm long, and many yellow disc florets. The species flowers anywhere between February and December but only after a fire has destroyed the overhead biomass or serious disturbance. It is an endemic species that is restricted to the Eastern Cape and Western Cape provinces of South Africa.