UV-B irradiation in rice: A general Glance About the Control of Oxidative Burst within the chloroplast lamellae

Ultraviolet-B (UV-B) radiation constitutes a minor part of the solar spectrum, being most of this radiation absorbed by the UV-screening stratospheric ozone layer. Yet, a global depletion of the ozone layer, largely due to the release of chlorofluorocarbons caused by human activities, is increasing solar UV-B radiation at the earth’s surface. Accordingly, in spite of considerable intra- and interspecific variability in sensitivity of crop plants, UV-B radiation is increasingly being absorbed by a large number of biomolecules (e.g., nucleic acids, proteins, lipids), therefore leading to their photoexcitation, what might promote changes on multiple biological processes, both with damaging or regulatory importance. Nevertheless, despite the diversity of UV targets in plants, depending of the growth conditions, the photosynthetic apparatus is amongst the main targets of UV-B, and its damage contributes significantly to the overall metabolic impairment. In this paper, a parallel is drawn between UV-B irradiation and the control of the oxidative burst exerted by Mn and ascorbate in the lamellae of Oryza sativa L.