Cytokinin deficiency causes distinct changes of sink and source parameters in tobacco shoots and roots

Cytokinin deficiency causes pleiotropic developmental changes such as reduced shoot and increased root growth. It was investigated whether cytokinin-deficient tobacco plants, which overproduce different cytokinin oxidase/dehydrogenase enzymes, show changes in different sink and source parameters, wh...

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Veröffentlicht in:Journal of experimental botany. - 1985. - 59(2008), 10 vom: 30., Seite 2659-72
1. Verfasser: Werner, Tomás (VerfasserIn)
Weitere Verfasser: Holst, Kerstin, Pörs, Yvonne, Guivarc'h, Anne, Mustroph, Angelika, Chriqui, Dominique, Grimm, Bernhard, Schmülling, Thomas
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2008
Zugriff auf das übergeordnete Werk:Journal of experimental botany
Schlagworte:Comparative Study Journal Article Research Support, Non-U.S. Gov't Carbohydrates cell cycle cytokinin cytokinin deficiency differentiation invertase meristem mehr... photosynthesis sink source Cytokinins Plant Proteins Adenosine Diphosphate 61D2G4IYVH Adenosine Triphosphate 8L70Q75FXE Oxidoreductases EC 1.- cytokinin oxidase EC 1.5.99.12
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245 1 0 |a Cytokinin deficiency causes distinct changes of sink and source parameters in tobacco shoots and roots 
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520 |a Cytokinin deficiency causes pleiotropic developmental changes such as reduced shoot and increased root growth. It was investigated whether cytokinin-deficient tobacco plants, which overproduce different cytokinin oxidase/dehydrogenase enzymes, show changes in different sink and source parameters, which could be causally related to the establishment of the cytokinin deficiency syndrome. Ultrastructural analysis revealed distinct changes in differentiating shoot tissues, including an increased vacuolation and an earlier differentiation of plastids, which showed partially disorganized thylakoid structures later in development. A comparison of the ploidy levels revealed an increased population of cells with a 4C DNA content during early stages of leaf development, indicating an inhibited progression from G2 to mitosis. To compare physiological characteristics of sink leaves, source leaves and roots of wild-type and cytokinin-deficient plants, several photosynthetic parameters, content of soluble sugars, starch and adenylates, as well as activities of enzymes of carbon assimilation and dissimilation were determined. Leaves of cytokinin-deficient plants contained less chlorophyll and non-photochemical quenching of young leaves was increased. However, absorption rate, photosynthetic capacity (F(v)/F(m) and J(CO2 max)) and efficiency (Phi CO(2 app)), as well as the content of soluble sugars, were not strongly altered in source leaves, indicating that chlorophyll is not limiting for photoassimilation and suggesting that source strength did not restrict shoot growth. By contrast, shoot sink tissues showed drastically reduced contents of soluble sugars, decreased activities of vacuolar invertases, and a reduced ATP content. These results strongly support a function of cytokinin in regulating shoot sink strength and its reduction may be a cause of the altered shoot phenotype. Roots of cytokinin-deficient plants contained less sugar compared with wild-type. However, this did not negatively affect glycolysis, ATP content, or root development. It is suggested that cytokinin-mediated regulation of the sink strength differs between roots and shoots 
650 4 |a Comparative Study 
650 4 |a Journal Article 
650 4 |a Research Support, Non-U.S. Gov't 
650 4 |a Carbohydrates 
650 4 |a cell cycle 
650 4 |a cytokinin 
650 4 |a cytokinin deficiency 
650 4 |a differentiation 
650 4 |a invertase 
650 4 |a meristem 
650 4 |a photosynthesis 
650 4 |a sink 
650 4 |a source 
650 7 |a Cytokinins  |2 NLM 
650 7 |a Plant Proteins  |2 NLM 
650 7 |a Adenosine Diphosphate  |2 NLM 
650 7 |a 61D2G4IYVH  |2 NLM 
650 7 |a Adenosine Triphosphate  |2 NLM 
650 7 |a 8L70Q75FXE  |2 NLM 
650 7 |a Oxidoreductases  |2 NLM 
650 7 |a EC 1.-  |2 NLM 
650 7 |a cytokinin oxidase  |2 NLM 
650 7 |a EC 1.5.99.12  |2 NLM 
700 1 |a Holst, Kerstin  |e verfasserin  |4 aut 
700 1 |a Pörs, Yvonne  |e verfasserin  |4 aut 
700 1 |a Guivarc'h, Anne  |e verfasserin  |4 aut 
700 1 |a Mustroph, Angelika  |e verfasserin  |4 aut 
700 1 |a Chriqui, Dominique  |e verfasserin  |4 aut 
700 1 |a Grimm, Bernhard  |e verfasserin  |4 aut 
700 1 |a Schmülling, Thomas  |e verfasserin  |4 aut 
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773 1 8 |g volume:59  |g year:2008  |g number:10  |g day:30  |g pages:2659-72 
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