The correlation between oxidative stress and leaf senescence during plant development.
In plants, besides being the final step leading to the death of the whole organism, senescence has a developmental function involving the coordinated degradation of macromolecules and the mobilization of nutrients out of senescing tissues into developing parts of the plant. Free radicals are thought to play an essential role in senescence, especially those derived from oxygen. Since these molecules are extremely toxic, the levels of the different reactive oxygen species have to be tightly regulated. However, at low concentrations, hydrogen peroxide may also serve as a signalling molecule. Therefore, a coordinated regulation of the free radical scavenging system, which comprises enzymatic components such as catalase, superoxide dismutase and ascorbate peroxidase, and non-enzymatic molecules such as ascorbate and glutathione is essential. The increased radical levels displayed during senescence are not only caused by the elevated production of radicals but also by a loss in antioxidant capacity.
Zimmermann
Petra
P
ZMBP, Centre of Plant Molecular Biology, University of Tübingen, Auf der Morgenstelle 28, 72076 Tübingen, Germany.
Zentgraf
Ulrike
U
D000375:Aging / Q000378:metabolism*; D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D018384:Oxidative Stress; D010100:Oxygen / Q000737:chemistry / Q000378:metabolism; D010544:Peroxidases / Q000378:metabolism; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000201:enzymology / Q000378:metabolism*; D018521:Plant Physiological Phenomena; D013482:Superoxide Dismutase / Q000378:metabolism
D005609:Free Radicals; D010937:Plant Growth Regulators; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D010100:Oxygen