Chapter 39. Singlet Oxygen in Higher Plants

Production of singlet oxygen in plants is primarily due to the photosensitizing activity of chlorophyll in chloroplasts during photosynthesis, when plants are exposed to light. Because of its high reactivity singlet oxygen initially had been considered to act as a cytotoxin that is responsible for photo-oxidative damage in plants under light stress. However, more recent work has revealed that singlet oxygen may also be perceived by plants as a signal that either triggers a genetically controlled programmed cell-death response or induces acclimation that enhances the plant's resistance against environmental challenges.