caa a22 4500 445841664 CHVBK 20180317145346.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s10725-011-9571-4 doi (NATIONALLICENCE)springer-10.1007/s10725-011-9571-4 Antioxidant enzymatic protection during tobacco leaf ageing is affected by cytokinin depletion [Elektronische Daten] [Zuzana Mýtinová, Václav Motyka, Daniel Haisel, Zuzana Lubovská, Alena Trávníčková, Petre Dobrev, Josef Holík, Naďa Wilhelmová] Plant ageing and senescence are associated with increased levels of reactive oxygen species. Level of cytokinins, the apparent inhibitors of plant senescence, is controlled by their irreversible degradation catalysed by cytokinin oxidase/dehydrogenase (CKX). We investigated the CKX activity, cytokinin concentration, and activities of antioxidative enzymes in tobacco (Nicotiana tabacum L. cv. Samsun NN) overexpressing the Arabidopsis gene for AtCKX2, targeted for extracellular secretion pathway. The control and AtCKX2 plants differed substantially in their phenotypes. When the lowest leaves in controls became yellow all leaves in AtCKX2 tobacco still remained green. Activities of antioxidant enzymes decreased with leaf age in both tobacco plants except for ascorbate peroxidase (APX) in the old leaves and glutathione reductase (GR) in young leaves. Enhancement of GR activity at all leaf stages, an increase of superoxide dismutase and a decline of catalase in young leaves, as well as an increase of APX in the oldest leaves were observed in AtCKX2 plant compared to control. Similar changes were detected after determination of isoenzymes on zymograms. It is evident that AtCKX2 plants had postponed onset of senescence despite the significantly lowered level of cytokinins. Enhanced antioxidant protection, especially in the oldest leaves, could subsidise this phenomenon. Springer Science+Business Media B.V., 2011 Ageing nationallicence Antioxidant enzymes nationallicence Cytokinins nationallicence Cytokinin oxidase/dehydrogenase nationallicence Tobacco nationallicence ABA : Abscisic acid nationallicence APX : Ascorbate peroxidase nationallicence AtCKX2 : Transgenic tobacco overexpressing the Arabidopsis gene for CKX2 nationallicence CAT : Catalase nationallicence cis Z : cis-zeatin nationallicence cis Z7G : cis-zeatin-7-glucoside nationallicence CKX : Cytokinin oxidase/dehydrogenase nationallicence DCPIP : 2,6-dichlorophenolindophenol nationallicence DTT : Dithiotreitol nationallicence EDTA : Ethylendiaminetetraacetic acid nationallicence GR : Glutathione reductase nationallicence GSSG : Oxidised glutathione nationallicence iP : N6-(Δ2-isopentenyl)adenine nationallicence iP7G : N6-(Δ2-isopentenyl)adenine-7-glucoside nationallicence MTT : 3(4,5-dimethyl-2-thiazolyl)-2,5diphenyl-2H-tetrazolium bromide nationallicence NBT : 3,3′-(3,3′-dimethoxy-4,4′-biphenylene)bis[2-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride] nationallicence PAR : Photosynthetically active radiation nationallicence ROS : Reactive oxygen species nationallicence SOD : Superoxide dismutase nationallicence TEMED : N,N,N′,N′-tetramethylethylenediamine nationallicence XTT : 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide, sodium salt nationallicence Z : trans-zeatin nationallicence Z7G : trans-zeatin-7-glucoside nationallicence Mýtinová Zuzana Academy of Sciences of the Czech Republic, v.v.i., Institute of Experimental Botany, Na Karlovce 1a, 160 00, Praha 6, Czech Republic aut Motyka Václav Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Rozvojová 263, 165 02, Praha 6, Czech Republic aut Haisel Daniel Academy of Sciences of the Czech Republic, v.v.i., Institute of Experimental Botany, Na Karlovce 1a, 160 00, Praha 6, Czech Republic aut Lubovská Zuzana Faculty of Science, Charles University, Albertov 6, 128 43, Praha 2, Czech Republic aut Trávníčková Alena Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Rozvojová 263, 165 02, Praha 6, Czech Republic aut Dobrev Petre Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Rozvojová 263, 165 02, Praha 6, Czech Republic aut Holík Josef Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Vídeňská 1083, 142 20, Praha 4, Czech Republic aut Wilhelmová Naďa Academy of Sciences of the Czech Republic, v.v.i., Institute of Experimental Botany, Na Karlovce 1a, 160 00, Praha 6, Czech Republic aut Plant Growth Regulation Springer Netherlands 65/1(2011-09-01), 23-34 0167-6903 65:1<23 2011 65 10725 https://doi.org/10.1007/s10725-011-9571-4 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10725-011-9571-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Mýtinová Zuzana Academy of Sciences of the Czech Republic, v.v.i., Institute of Experimental Botany, Na Karlovce 1a, 160 00, Praha 6, Czech Republic aut NATIONALLICENCE 700 1- Motyka Václav Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Rozvojová 263, 165 02, Praha 6, Czech Republic aut NATIONALLICENCE 700 1- Haisel Daniel Academy of Sciences of the Czech Republic, v.v.i., Institute of Experimental Botany, Na Karlovce 1a, 160 00, Praha 6, Czech Republic aut NATIONALLICENCE 700 1- Lubovská Zuzana Faculty of Science, Charles University, Albertov 6, 128 43, Praha 2, Czech Republic aut NATIONALLICENCE 700 1- Trávníčková Alena Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Rozvojová 263, 165 02, Praha 6, Czech Republic aut NATIONALLICENCE 700 1- Dobrev Petre Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Rozvojová 263, 165 02, Praha 6, Czech Republic aut NATIONALLICENCE 700 1- Holík Josef Academy of Sciences of the Czech Republic, Institute of Experimental Botany, Vídeňská 1083, 142 20, Praha 4, Czech Republic aut NATIONALLICENCE 700 1- Wilhelmová Naďa Academy of Sciences of the Czech Republic, v.v.i., Institute of Experimental Botany, Na Karlovce 1a, 160 00, Praha 6, Czech Republic aut NATIONALLICENCE 773 0- Plant Growth Regulation Springer Netherlands 65/1(2011-09-01), 23-34 0167-6903 65:1<23 2011 65 10725 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer