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Antioxidant protection during ageing and senescence in chloroplasts of tobacco with modulated life span
Author(s) -
Procházková Dagmar,
Haisel Daniel,
Wilhelmová Nad'a
Publication year - 2008
Publication title -
cell biochemistry and function
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.933
H-Index - 61
eISSN - 1099-0844
pISSN - 0263-6484
DOI - 10.1002/cbf.1481
Subject(s) - chloroplast , senescence , antioxidant , apx , ageing , cytokinin , nicotiana tabacum , biology , botany , microbiology and biotechnology , biochemistry , gene , auxin , genetics , catalase
Abstract We studied changes in antioxidant protection during ageing and senescence in chloroplasts of tobacco ( Nicotiana tabacum L., cv. Wisconsin) with introduced SAG 12 promoter fused with ipt gene for cytokinin synthesis (transgenic plants with increased levels of cytokinins, SAG) or without it (control). Old leaves of SAG plants as well as their chloroplasts maintained higher physiological parameters compared to controls; accordingly, we concluded that their ageing was diverted due to increased cytokinin content. The chloroplast antioxidant protection did not decrease as well. Although antioxidant protection usually decreased in whole leaves of senescing control plants, ascorbate peroxidase (APX) and dehydroascorbate reductase (DHAR) activity, which maintained the high redox state of ascorbate, increased in chloroplasts of old control leaves. Copyright © 2008 John Wiley & Sons, Ltd.