Protection against oxygen radicals: an important defence mechanism studied in transgenic plants

作者：Christine Helen Foyer, P. DESCOURVIÈRES, Kunert Kj · 发表于：Plant Cell & Environment · 年份：1994 · DOI：10.1111/j.1365-3040.1994.tb00146.x · 被引用次数：1255 · 研究领域：Photosynthetic Processes and Mechanisms、Plant Stress Responses and Tolerance、Plant responses to elevated CO2

ABSTRACT Free radicals and other active derivatives of oxygen are inevitable by‐products of biological redox reactions. Reduced oxygen species, such as hydrogen peroxide, the superoxide radical anion and hydroxyl radicals, inactivate enzymes and damage important cellular components. In addition, singlet oxygen, produced via formation of triplet state chlorophyll, is highly destructive. This oxygen species initiates lipid peroxidation, and produces lipid peroxy radicals and lipid hydroperoxides that are also very reactive. The increased production of toxic oxygen derivatives is considered to be a universal or common feature of stress conditions. Plants and other organisms have evolved a wide range of mechanisms to contend with this problem. The antioxidant defence system of the plant comprises a variety of antioxidant molecules and enzymes. Considerable interest has been focused on the ascorbate‐glutathione cycle because it has a central role in protecting the chloroplasts and other cellular compartments from oxidative damage. It is clear that the capacity and activity of the antioxidative defence systems are important in limiting photo‐oxidative damage and in destroying active oxygen species that are produced in excess of those normally required for signal transduction or metabolism. In our studies on this system, we became aware that the answers to many unresolved questions concerning the nature and regulation of the antioxidative defence system could not be obtained easily ...