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CYTOKININS AND THE GROWTH OF CULTURED SYCAMORE CELLS
Author(s) -
MACKENZIE I. A.,
KONAR APARNA,
STREET H. E.
Publication year - 1972
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.1972.tb01273.x
Subject(s) - cytokinin , kinetin , zeatin , cell division , endogeny , biology , microbiology and biotechnology , cell growth , cell culture , botany , lag , auxin , tissue culture , cell , biochemistry , genetics , in vitro , gene , computer network , computer science
S ummary Externally supplied cytokinins can induce cell division in sycamore cultures at cell densities at which, in the absence of a supply of cytokinin, they fail to grow. When cultures are initiated at cell densities where growth occurs in the absence of added cytokinins only after a long lag phase, the addition of cytokinins reduces the length of the lag phase. In these effects zeatin is fully effective at much lower concentrations than kinetin. As the duration of stationary phase is increased in the stock cultures, the ability of the cells to grow from a low initial cell density declines. This appears to be due to their declining endogenous cytokinin activity and declining ability to take up added cytokinin from their culture medium. It is postulated that, during the lag phase, the cells develop a critical level of cytokinin activity by an excess of endogenous synthesis over loss to the culture medium and internal degradation. When the phase of cell division has been initiated, the subsequent growth of the cultures is unaffected by low external levels of cytokinins.