Molecular Mechanisms of Photoinhibition in Plants: A Review

Abstract

Through the process of electron transport along a series of redox processes, sunlight energy is transformed into chemical energy that is then stored during photosynthesis. Photoinhibition is a significant and extremely complex phenomenon, which is basically light-induced damage to the photosynthetic machinery that principally affects the Photosystem II complex and leads to less photosynthetic productivity. A light-independent photosynthetic activity restricts the consumption of electrons produced in the early photoreactions, which appears to be the principal cause of photoinhibition by visible light. There is a chance that excessive photosynthetic electron transport could lead to an overabundance of reactive oxygen species (ROS). Reactive oxygen species such as H2O2 and O2, that develops in photosystem II as a result of exposure to intense light, start to damage electron transfer system components and protein structure. Plants have adapted several protective mechanisms like production of antioxidants, enzymes and carotenoids to face reactive oxygen species and avoid photoinhibition. This article provides overview of molecular mechanisms involved in photoinhibition and its protective elements.