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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 fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plant Hormone
Plant hormones (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, including embryogenesis, the regulation of Organ (anatomy), organ size, pathogen defense, Stress (biology), stress tolerance and Reproduction, reproductive development. Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones. Frits Warmolt Went, 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 vascular plant, vascular plants ("higher plants"). Some phytohormones also occur in microorganisms, such as unicellular fungus, fungi and bacteria, however in these cases they do not play a hormonal role and can better be regarded as secondary metabolites. Characteristi ... [...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 cytokinin-like synthetic plant hormone that promotes cell division in plants. Kinetin was originally isolated by Carlos O. 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 to induce callus formation (in conjunction with auxin) and 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 degraded when 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, inc ... [...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 ge ... [...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. DPU is a cytokinin 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 (biology), cell growth and cellular differentiation, differentiation, but also affect apical ..., a type of plant hormone that induces flower development. The cytokinin effect of DPU is relatively low, but other more potent phenylurea-type cytokinins have been reported. It was detected in coconut milk. References External links * Cytokinins Ureas {{Organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
6-benzylaminopurine
6-Benzylaminopurine, benzyl adenine, BAP or BA is a first-generation synthetic cytokinin that elicits plant growth and development responses, setting blossoms and stimulating fruit richness by stimulating cell division. It is an inhibitor of respiratory kinase in plants, and increases post-harvest life of green vegetables. Influence of cytokinin as 6-benzylaminopurine (BAP) in combination with other methods on postharvest green color retention on broccoli heads and asparagus spears, showed positive results for quality retention. Treatment with 10 and 15 ppm BAP can be used to extend shelf life of fresh-cut broccoli florets and shredded cabbage during storage at 6±1°C at commercial level. It can be used to extend the shelf life of flowers and cut greens in floristry. The shelf life of cut shoots of ''Polygonatum multiflorum'' 'Variegatum' kept in water is about 7 days. To extend their life after cutting, conditioning with gibberellic acid or BA is used. This doubles their possib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Van Overbeek
Johannes is a Medieval Latin form of the personal name that usually appears as " John" in English language contexts. It is a variant of the Greek and Classical Latin variants (Ιωάννης, '' Ioannes''), itself derived from the Hebrew name '' Yehochanan'', meaning " YHWH is gracious". The name became popular in Northern Europe, especially in Germany because of Christianity. Common German variants for Johannes are ''Johann'', ''Hannes'', '' Hans'' (diminutized to ''Hänschen'' or ''Hänsel'', as known from "'' Hansel and Gretel''", a fairy tale by the Grimm brothers), '' Jens'' (from Danish) and '' Jan'' (from Dutch, and found in many countries). In the Netherlands, Johannes was without interruption the most common masculine birth name until 1989. The English equivalent for Johannes is John. In other languages *Joan, Jan, Gjon, Gjin and Gjovalin in Albanian *'' Yoe'' or '' Yohe'', uncommon American form''Dictionary of American Family Names'', Oxford University Press, 2013. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endosperm
The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the Embryo#Plant embryos, embryo and provides nutrition in the form of starch, though it can also contain Vegetable oil, oils and protein. This can make endosperm a source of nutrition in animal diet. For example, wheat endosperm is ground into flour for bread (the rest of the grain is included as well in whole wheat flour), while barley endosperm is the main source of sugars for beer production. Other examples of endosperm that forms the bulk of the edible portion are coconut "meat" and coconut "water", and Maize, corn. Some plants, such as certain orchids, lack endosperm in their seeds. Ancestral flowering plants have seeds with small embryos and abundant endosperm. In some modern flowering plants the embryo occupies most of the seed and the endosperm ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coconut
The coconut tree (''Cocos nucifera'') is a member of the palm tree family (biology), family (Arecaceae) and the only living species of the genus ''Cocos''. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the fruit, which botanically is a drupe, not a Nut (fruit), nut. Originally native to Central Indo-Pacific, they are now ubiquitous in coastal tropical regions and are a cultural icon of the tropics. The coconut tree provides food, fuel, cosmetics, folk medicine and building materials, among many other uses. The inner flesh of the mature seed, as well as the coconut milk extracted from it, forms a regular part of the diets of many people in the tropics and subtropics. Coconuts are distinct from other fruits because their endosperm contains a large quantity of an almost clear liquid, called "coconut water" or "coconut juice". Mature, ripe coconuts can be used as edible seeds, or processed for Coconut oil, oil and Coconut milk, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytokine
Cytokines () are a broad and loose category of small proteins (~5–25 kDa) important in cell signaling. Cytokines are produced by a broad range of cells, including immune cells like macrophages, B cell, B lymphocytes, T cell, T lymphocytes and mast cells, as well as Endothelium, endothelial cells, fibroblasts, and various stromal cells; a given cytokine may be produced by more than one type of cell. Due to their size, cytokines cannot cross the lipid bilayer of cells to enter the cytoplasm and therefore typically exert their functions by interacting with specific cytokine receptor, cytokine receptors on the target cell surface. Cytokines are especially important in the immune system; cytokines modulate the balance between humoral immunity, humoral and cell-mediated immunity, cell-based immune responses, and they regulate the maturation, growth, and responsiveness of particular cell populations. Some cytokines enhance or inhibit the action of other cytokines in complex way ... [...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. This tissue system is present between the dermal tissue and forms the main bulk of the plant body. # 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 the plant. #Aerenchyma cells are found in aquatic plants. They are also known to be parenchyma cells with large air cavities surrounded by irregular cell ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
