著者

Eklof Staffan Astot Crister Blackwell John Thomas Moritz Olof Olsson Goran Sandberg Department of Forest Genetics and Plant physiology SwedishUniversity of Agricltural sciences Department of Forest Genetics and Plant physiology SwedishUniversity of Agricltural sciences Department of Forest Genetics and Plant physiology SwedishUniversity of Agricltural sciences Department of Forest Genetics and Plant physiology SwedishUniversity of Agricltural sciences Department of Molecular Biology Goteborg University Department of Forest Genetics and Plant physiology SwedishUniversity of Agricltural sciences

出版者

Japanese Society of Plant Physiologists

雑誌

Plant and cell physiology (ISSN:00320781)

巻号頁・発行日

vol.38, no.3, pp.225-235, 1997-03

参考文献数

59

被引用文献数

3

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Cytokinins and auxins are important regulators of plant growth and development, but there is incomplete and conflicting evidence that auxins affect cytokinin metabolism and vice versa. We have investigated these interactions in Nicotiana tabacum L. by separate in planta manipulation of levels of the hormones followed by analysis of the induced changes in the metabolism of the other hormone. Cytokinin-overproducing plants (expressing the Agrobacterium tumefaciens ipt gene) had lower than wild-type levels of free IAA, and reduced rates of IAA synthesis and turn-over, but there were no differences in the profiles of metabolites they produced from fed IAA. Similarly, auxin-over-producing plants (expressing the A. tumefaciens iaaM and iaaH genes), had lower levels of the major cytokinins than wild-type plants and lower cytokinin oxidase activity, but there were no differences in the profiles of metabolites they produced from fed cytokinins. The data demonstrate that cytokinin or auxin overproduction decreases the content of the other hormone, apparently by decreasing its rate of synthesis and/or transport, rather than by increasing rates of turnover or conjugation. Implications for the importance of cytokinin : auxin ratios in plant development are considered.