Photoprotection (plants)

Article By:

Adams, William, III. Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado.

Demmig-Adams, Barbara Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, Colorado.

Last reviewed:January 2021

DOI:https://doi.org/10.1036/1097-8542.900153

Any plant mechanism that serves to prevent photodamage, that is, damage caused by light. A cascade of mechanisms at different scales contributes toward photoprotection in plants: (1) preemptive reduction of the absorption of potentially harmful electromagnetic radiation or interception (screening) of radiation before it reaches those plant components susceptible to photodamage, (2) reradiation of excess absorbed excitation energy back into the environment as harmless heat, and (3) detoxification of toxic radicals formed by excessive excitation energy. The second mechanism is a particularly powerful and flexible outlet to dispose of potentially harmful energy; it is finely regulated on multiple time scales (from seconds to seasons), is engaged only when needed and disengaged when light is not excessive, and allows maximum use of absorbed light for photosynthesis. See also: Absorption of electromagnetic radiation; Electromagnetic radiation; Light; Photochemistry; Photosynthesis

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