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Regulation of cytokinin content in plant cells
Author(s) -
Kamínek Miroslav,
Motyka Václav,
Vaňková Radomíra
Publication year - 1997
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1997.tb01053.x
Subject(s) - cytokinin , intracellular , auxin , biochemistry , microbiology and biotechnology , biology , plant cell , extracellular , biosynthesis , plant physiology , chemistry , botany , enzyme , gene
Cytokinin levels in plant cells are dependent on cytokinin biosynthesis and/or uptake from extracellular sources, metabolic interconversions, inactivation and degradation. Cytokinin conversion to compounds differing in polarity seems to be decisive for their entrapment within the cell and intracellular compartmentation, which affects their metabolic stability. Increase in cytokinin levels, resulting either from their uptake or intracellular biosynthesis, may promote further autoinductive accumulation of cytokinins which may function in the induction of cytokinin‐initiated physiological processes. Accumulated cytokinins are capable of inducing cytokinin oxidase which consequently decreases cytokinin levels. This seems to be the mechanism of re‐establishment and maintenance of cytokinin homeostasis required for further development of physiological events induced by transient cytokinin accumulation. Auxin may influence cytokinin levels by down regulation of cytokinin biosynthesis and/or by promotion of cytokinin degradation. A model of the regulation of cytokinin levels in plant cells based on these phenomena is presented and its physiological role(s) is discussed.