Cytokinin promotes catalase and ascorbate peroxidase activities and preserves the chloroplast integrity during dark-senescence

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dc.contributor.author Vargas-Suarez, M.
dc.contributor.author Lopez-Delgado, H.
dc.contributor.author Trevilla-Garcia, C.
dc.contributor.author Zavaleta-Mancera, H. A.
dc.contributor.author Loza-Tavera, H.
dc.contributor.author Ougham, Helen J.
dc.contributor.author Mora-Herrera, M. E.
dc.date.accessioned 2009-07-08T14:23:29Z
dc.date.available 2009-07-08T14:23:29Z
dc.date.issued 2007-12-03
dc.identifier.citation Vargas-Suarez , M , Lopez-Delgado , H , Trevilla-Garcia , C , Zavaleta-Mancera , H A , Loza-Tavera , H , Ougham , H J & Mora-Herrera , M E 2007 , ' Cytokinin promotes catalase and ascorbate peroxidase activities and preserves the chloroplast integrity during dark-senescence ' Journal of Plant Physiology , vol 164 , no. 12 , pp. 1572-1582 . , 10.1016/j.jplph.2007.02.003 en
dc.identifier.issn 1618-1328
dc.identifier.other PURE: 107572
dc.identifier.other dspace: 2160/2569
dc.identifier.uri http://hdl.handle.net/2160/2569
dc.description Zavaleta-Mancera, H. A., Lopez-Delgado, H., Loza-Tavera, H., Mora-Herrera, M., Trevilla-Garcia, C., Vargas-Suarez, M., Ougham, H. J. (2007). Cytokinin promotes catalase and ascorbate peroxidase activities and preserves the chloroplast integrity during dark-senescence.   Journal of Plant Physiology, 164, (12), 1572-1582. Sponsorship: Mexican Council of Science and Technology, CONACYT (grant 43866/A-1); BBSRC en
dc.description.abstract Increased oxidative stress displayed during dark-senescence of wheat leaves (Triticum aestivum L.) is caused not only by the increased levels of radicals but also by a loss of antioxidant capacity. Mature leaves were incubated in 6-benzylaminopurine (BAP 10−4 M) or water (control) during 6 d in the dark. The senescence-delaying effect of BAP was associated with the retention of the chloroplast structure, 60% of the initial content of chlorophyll (Chl) and 77% of the initial content of protein. BAP reduced the degradation of the light-harvesting chlorophyll a/b binding protein (LHCP-2), and the large (LSU) and small subunits (SSU) of Rubisco. Our results indicated that the presence of the NADPH:protochlorophyllide oxidoreductase (POR, EC.1.6.99.1) was not promoted by the cytokinin, leading to the conclusion that BAP maintains the level of Chl, preventing its degradation, rather than inducing Chl biosynthesis. The internal structure of chloroplasts was maintained in BAP-treated leaves for up to 6 d, with well-organized grana thylakoids and small plastoglobuli; in contrast, chloroplasts of control leaves deteriorated rapidly from day 4 with disorganized internal membranes, and more and larger plastoglobuli. BAP increased the activities of catalase (CAT, EC 1.11.1.6) and ascorbate peroxidase (APX, EC 1.11.1.11) and reduced the level of H2O2 in the delayed-senescence tissue. The present research indicates that BAP reduces levels of reactive oxygen species (ROS), and enhances the activity of antioxidant enzymes (CAT, APX). Our results suggest that BAP protects the cell membranes and the photosynthetic machinery from oxidative damage during delay of senescence in the dark. en
dc.format.extent 11 en
dc.language.iso eng
dc.relation.ispartof Journal of Plant Physiology en
dc.subject Ascorbate peroxidase en
dc.subject Catalase en
dc.subject Chloroplast en
dc.subject Cytokinin en
dc.subject ROS en
dc.title Cytokinin promotes catalase and ascorbate peroxidase activities and preserves the chloroplast integrity during dark-senescence en
dc.type Text en
dc.type.publicationtype Article (Journal) en
dc.identifier.doi http://dx.doi.org/10.1016/j.jplph.2007.02.003
dc.contributor.institution Institute of Biological, Environmental and Rural Sciences en
dc.description.status Peer reviewed en


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