title: Molecular mechanisms of light stress of photosynthesis.
abstract: Photosynthesis is the basic energy conversion process on Earth, which makes possible the utilization of the energy of sunlight for living organisms. However, light is not only the basic driving force of photosynthesis, but also an important stress factor at the same time. Light-induced decline of photosynthetic activity, generally denoted as photoinhibition, is a general phenomenon in all oxygenic photosynthetic organism under conditions when the metabolic processes cannot keep up with the electron flow produced by the primary photoreactions. Although light-induced damage occurs in all pigmented photosynthetic complexes the primary site of photoinhibition is the photosystem II (PSII) complex, which performs light-driven oxidation of water to protons and oxygen. The main factors, which are responsible for the light sensitivity of photosystem II, are excited pigment molecules, oxygen, manganese, as well as electron donors with high-oxidizing potential. Photosystem II can be efficiently protected from photodamage by the combination of harmless dissipation of absorbed light energy, nonradiative charge recombination, and repair of damaged reaction center complexes, making possible the safe utilization of light, the highly energetic substrate of photosynthesis.
authors.affiliation: Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62, Hungary. imre@brc.hu
authors.forename: Imre
authors.initials: I
authors.lastname: Vass
authors.forename: Krisztián
authors.initials: K
authors.lastname: Cser
authors.forename: Otilia
authors.initials: O
authors.lastname: Cheregi
mesh_terms: D008027:Light / Q000009:adverse effects; D010788:Photosynthesis / Q000502:physiology* / Q000528:radiation effects; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism* / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D045322:Photosynthetic Reaction Center Complex Proteins