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The discovery of cytokinins and its physiological function

Cytokinins are a rank of insert hormones with adenine round structure. The typical side is in the sixth grade of adenine sphere has a specific substituent Their physiological functions prominently performance in promoting cell schism and cause germinate 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 young In 1955 Miller in the degradationproduct of yeast DNA and herring sperms DNA processed from a substance can promotecell division, recognized as kinetin, its chemical shelf is furan methyl adenine,also declared as furfuryl gland purine In 1963 Latham from the 11-16 daysfertilized corn seeds isolated the finest one average 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 embed to the derive Leaves, buds, spawn fruit anddeveloping seeds can be formed cytokinin, zeatin is the top obtained from themaize immature seeds. Cytokinin can engender by jettison RNA cleavage, moreover canthrough medroxyprogesterone valerate and adenine as a precursor synthesis

As a plant growth regulator, cytokinin has a variety of physiological effects Itsphysiological effects were as follows: firstly, nurse cell division,cytokinins paramount physiological function is to boost cell division. Auxins,gibberellins and cytokinins keep 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 division of the cytoplasm The cytokinin was mainlyworked on the cytoplasmic division. Second, doctor buds division Promote buddifferentiation is one of the superior physiological effects of cytokinin,some sovereign detached leaves treated with cytokinin, the needle margins basalveins can generate 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 indirect thickening Fourth,promote edgewise sprout developing, eliminating the finest verge Cells can free theapical dominance caused by protuberance hormone, boost sidelong grow node anddevelopment. Such as pea sprouts dropped cytokinin explanation in leaf axils part,buds can flourish and establish Fifth, delay flag aging If partially coated withcytokinin in impartial leaves, the remaining parts of the leaves yellowing andaging, sully kinetin parts remain alert green. Due to the cytokinin retain the effectof remaining raw and anti-aging, so it can be used to deal with raw fruitand flowers to remain unfinished and green, stop fruit delete For example, withcytokinin to doctor successors citrus fruit can significantly dissuade fruit drop, andoverstriking stems, black raw fruit, compared with the break group, the fruitalso significantly increased Break aficionado dormancy. Need illuminate seeds, such aslettuce and tobacco could not sprout in the dark, use cytokinin can insteadof embellish to discontinue the dormancy of this seed, nurture germinating

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