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Cytokinins
Cytokinins (CK) are a class of plant hormones that promote cell division, or cytokinesis, in plant roots and shoots. They are involved primarily in cell growth and differentiation, but also affect apical dominance, axillary bud growth, and leaf senescence. There are two types of cytokinins: adenine-type cytokinins represented by kinetin, zeatin, and 6-benzylaminopurine, and phenylurea-type cytokinins like diphenylurea and thidiazuron (TDZ). Most adenine-type cytokinins are synthesized in roots. Cambium and other actively dividing tissues also synthesize cytokinins. No phenylurea cytokinins have been found in plants. Cytokinins participate in local and long-distance signalling, with the same transport mechanism as purines and nucleosides. Typically, cytokinins are transported in the xylem. Cytokinins act in concert with auxin, another plant growth hormone. The two are complementary, having generally opposite effects. History The idea of specific substances required ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Hormone
Plant hormone (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development. Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book. Phytohormones occur across the plant kingdom, and even in algae, where they have similar functions to those seen in higher plants. Some phytohormones also occur in microorganisms, such as unicellular fungi and bacteria, however in these cases they do not play a hormonal role and can better be regarded as secondary metabolites. Characteristics The word hormone is derived from Greek, meaning ''set in motion''. Plant hormones affect gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeatin
Zeatin is a cytokinin derived from adenine, which occurs in the form of a ''cis''- and a ''trans''-isomer and conjugates. Zeatin was discovered in immature corn kernels from the genus '' Zea''. It promotes growth of lateral buds and when sprayed on meristems stimulates cell division to produce bushier plants. Occurrence Zeatin and its derivatives occur in many plant extracts and are the active ingredient in coconut milk, which causes plant growth. 6-(γ,γ-Dimethylallylamino)purine is a zeatin precursor. Application Zeatin has a variety of effects including: # Promotes callus initiation when combined with auxin, concentration 1 ppm. # Promotes fruit set. Zeatin 100 ppm + GA3 500 ppm + NAA 20 ppm, sprayed at 10th, 25th, 40th day after blossom. # Retards yellowing for vegetables, 20 ppm, sprayed. # Causes auxiliary stems to grow and flower. Zeatin can also be applied to stimulate seed germination and seedling growth. Zeatin has also been shown to promote the resistance of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kinetin
Kinetin (/'kaɪnɪtɪn/) is a type of cytokinin, a class of plant hormone that promotes cell division. Kinetin was originally isolated by Carlos Miller and Skoog ''et al.'' as a compound from autoclaved herring sperm DNA that had cell division-promoting activity. It was given the name kinetin because of its ability to induce cell division, provided that auxin was present in the medium. Kinetin is often used in plant tissue culture for inducing formation of callus (in conjunction with auxin) and to regenerate shoot tissues from callus (with lower auxin concentration). For a long time, it was believed that kinetin was an artifact produced from the deoxyadenosine residues in DNA, which degrade on standing for long periods or when heated during the isolation procedure. Therefore, it was thought that kinetin does not occur naturally, but, since 1996, it has been shown by several researchers that kinetin exists naturally in the DNA of cells of almost all organisms tested so far, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diphenylurea
1,3-Diphenylurea is a phenylurea-type compound with the formula (PhNH)2CO (Ph = C6H5). It is a colorless solid that is prepared by transamidation of urea with aniline Aniline is an organic compound with the formula C6 H5 NH2. Consisting of a phenyl group attached to an amino group, aniline is the simplest aromatic amine. It is an industrially significant commodity chemical, as well as a versatile start .... DPU is a cytokinin, a type of plant hormone that induces flower development. It occurs in coconut milk. The cytokinin effect of DPU is relatively low, but other more potent phenylurea-type cytokinins have been reported.Effect of cytokinin-active phenylurea derivatives on shoot multiplication. T. Genkov and I. Ivanova, Bulg. J. Plant Physiol., 1995, 21(1), pages 73–83link to article at researchgate References External links * Cytokinins Ureas {{Organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Senescence
Plant senescence is the process of aging in plants. Plants have both stress-induced and age-related developmental aging. Chlorophyll degradation during leaf senescence reveals the carotenoids, such as anthocyanin and xanthophylls, which are the cause of autumn leaf color in deciduous trees. Leaf senescence has the important function of recycling nutrients, mostly nitrogen, to growing and storage organs of the plant. Unlike animals, plants continually form new organs and older organs undergo a highly regulated senescence program to maximize nutrient export. Hormonal regulation of senescence Programmed senescence seems to be heavily influenced by plant hormones. The hormones abscisic acid, ethylene, jasmonic acid and salicylic acid are accepted by most scientists as promoters of senescence, but at least one source lists gibberellins, brassinosteroids and strigolactone as also being involved. Cytokinins help to maintain the plant cell and expression of cytokinin biosynthesis gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aleksander Jabłoński
Professor Aleksander Jabłoński (born 26 February 1898 in Woskresenówka, in Imperial Russia, died 9 September 1980 in Skierniewice, Poland) was a Polish physicist and member of the Polish Academy of Sciences. His research was in molecular spectroscopy and photophysics. Life and career He was born on 26 February 1898 in Woskresenówka near Kharkiv in Imperial Russia. He attended ''Gymnasium'' high school in Kharkiv as well as a music school where he learned to play the violin under supervision of Konstanty Gorski. In 1916, he started to study physics at the University of Kharkiv. During the World War I he served in the Polish I Corps in Russia. After the war he settled in Warsaw in 1918. In 1919-1920 he fought for Poland against aggression by Soviet Russia (and was consequently decorated with the Polish Cross of Valour). Jabłoński initially studied the violin at Warsaw Conservatory, under the virtuoso Stanisław Barcewicz, but later switched to science. He received a Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Datura
''Datura'' is a genus of nine species of highly poisonous, vespertine-flowering plants belonging to the nightshade family Solanaceae. They are commonly known as thornapples or jimsonweeds, but are also known as devil's trumpets (not to be confused with angel's trumpets, which are placed in the closely related genus '' Brugmansia''). Other English common names include moonflower, devil's weed, and hell's bells. All species of ''Datura'' are extremely poisonous and potentially psychoactive, especially their seeds and flowers, which can cause respiratory depression, arrhythmias, fever, delirium, hallucinations, anticholinergic syndrome, psychosis, and even death if taken internally. Due to their effects and symptoms, they have occasionally been used not only as poisons, but also as hallucinogens by various groups throughout history. Traditionally, psychoactive administration of ''Datura'' species has often been associated with witchcraft and sorcery or similar practices in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parenchyma (botany)
The ground tissue of plants includes all tissues that are neither dermal nor vascular. It can be divided into three types based on the nature of the cell walls. # Parenchyma cells have thin primary walls and usually remain alive after they become mature. Parenchyma forms the "filler" tissue in the soft parts of plants, and is usually present in cortex, pericycle, pith, and medullary rays in primary stem and root. # Collenchyma cells have thin primary walls with some areas of secondary thickening. Collenchyma provides extra mechanical and structural support, particularly in regions of new growth. # Sclerenchyma cells have thick lignified secondary walls and often die when mature. Sclerenchyma provides the main structural support to a plant. Parenchyma Parenchyma is a versatile ground tissue that generally constitutes the "filler" tissue in soft parts of plants. It forms, among other things, the cortex (outer region) and pith (central region) of stems, the cortex of roots, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Folke K
Folke is a parish in the county of Dorset in southern England, situated in the Blackmore Vale, approximately south-east of Sherborne. The parish has an area of and is made of the villages of Folke and Alweston, and the hamlet of Bishops Down. Dorset County Council's 2013 estimate of the population of Folke parish is 270. In the 2011 census figures have been published for the population of Folke parish combined with the small parish of North Wootton to the north; this was 339. The Manor House in the hamlet of Folke dates from about 1500 and adjoins the early 17th-century parish church. The house of Font le Roi, sited by the road towards Sturminster Newton, was built as a gatehouse in the 15th century. Folke Wood Folke Wood is a wood near Folke in Dorset, England. It was planted by the Woodland Trust The Woodland Trust is the largest woodland conservation charity in the United Kingdom and is concerned with the creation, protection, and restoration of ... is nearby. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carlos O
Carlos may refer to: Places ;Canada * Carlos, Alberta, a locality ;United States * Carlos, Indiana, an unincorporated community * Carlos, Maryland, a place in Allegany County * Carlos, Minnesota, a small city * Carlos, West Virginia ;Elsewhere * Carlos (crater), Montes Apenninus, LQ12, Moon; a lunar crater near Mons Hadley People * Carlos (given name), including a list of name holders * Carlos (surname), including a list of name holders Sportspeople * Carlos (Timorese footballer) (born 1986) * Carlos (footballer, born 1995), Brazilian footballer * Carlos (footballer, born 1985), Brazilian footballer Others * Carlos (Calusa) (died 1567), king or paramount chief of the Calusa people of Southwest Florida * Carlos (DJ) (born 1966), British DJ * Carlos (singer) (1943—2008), French entertainer * Carlos the Jackal, a Venezuelan terrorist *Carlos (DJ) (born 2010) Guyanese DJ Arts and entertainment * ''Carlos'' (miniseries), 2010 biopic about the terrorist Carlos the Jackal * ''C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
