The discovery of cytokinins and its physiological function

Cytokinins are a rank of imbed hormones with adenine ring structure. The average facet is in the sixth position of adenine round has a specific substituent Their physiological functions prominently stunt in promoting cell separation and prompt develop formation

The discovery of cytokinins and its physiological function

In 1948US. Skog and China Cui Cheng found adenine in tobacco tissue cultures caninduce tobacco kernel tissue differentiation and nascent In 1955 Miller in the degradationproduct of yeast DNA and herring sperms DNA processed from a substance can promotecell division, avowed as kinetin, its chemical form is furan methyl adenine,also published as furfuryl gland purine In 1963 Latham from the 11-16 daysfertilized corn seeds isolated the elite one common cytokinin exist in thehigher plants, and named zeatin Currently had been getseveral adenine derivatives from the higher plants, such as dihydro zeatin,zeatin riboside and isopentenyl adenine Now there are a variety of synthetic similarlymaterials, such as benzyl adenine, tetrahydropyranyl benzyl adenine They areknown as cytokinin

Rootmeristem (apical) synthesize cytokinin is the most active, long-range transportthrough the xylem from the root to the proceed Leaves, buds, successors fruit anddeveloping seeds can be formed cytokinin, zeatin is the blessing obtained from themaize immature seeds. Cytokinin can generate by unburden RNA cleavage, moreover canthrough medroxyprogesterone valerate and adenine as a precursor synthesis

As a plant excrescence regulator, cytokinin has a variety of physiological effects Itsphysiological effects were as follows: firstly, cherish cell division,cytokinins main physiological function is to nurse cell division. Auxins,gibberellins and cytokinins retain the cause of promoting cell division, buteach of them has different role Auxin is only promoting nuclear division,which has nil to do with the breach of the cytoplasm The cytokinin was mainlyworked on the cytoplasmic disunion Second, promote buds breach Promote buddifferentiation is one of the famous physiological effects of cytokinin,some king detached leaves treated with cytokinin, the needle margins basalveins can create buds Third, encourage cell expansion Cytokinins can promotesome of dicotyledonous plants such as beans, radish expanding cotyledon or leafdiscs, mostly because such expansion promotes cell sidewise thickening Fourth,promote indirect develop developing, eliminating the finest limits Cells can free theapical dominance caused by growth hormone, cherish sideward grow nodule anddevelopment. Such as pea sprouts dropped cytokinin solution in needle axils part,buds can evolve and flourish Fifth, delay flag aging If partially coated withcytokinin in objective leaves, the remaining parts of the leaves yellowing andaging, bespatter kinetin parts remain receptive coarse Due to the cytokinin keep the effectof remaining raw and anti-aging, so it can be used to covenant with fresh fruitand flowers to remain unprepared and green, prevent fruit drop For example, withcytokinin to cherish offspring citrus fruit can significantly discourage fruit drop, andoverstriking stems, black coarse fruit, compared with the curb group, the fruitalso significantly increased Break seed dormancy Need illuminate seeds, such aslettuce and tobacco could not germinate in the dark, use cytokinin can insteadof light to pause the dormancy of this seed, tend germinating

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