Photooxidative stress

Abstract

Plants are exposed to several environmental stresses, that adversely affect metabolism, growth and yield. Yet, plants are also known to adapt to these stress conditions by modulating their metabolism and physiology. These stress factors include abiotic (drought, salinity, light, CO2, soil nutrients and temperature) and biotic (bacteria, fungi, viruses and insects) components. Among abiotic factors, non-optimal light intensity and temperature can be considered as the most serious limiting factors which limit the growth and yield of plants (Foyer, 2002; Reddy et al., 2004). Also, environmental fluctuations often result in 'stress' which ultimately limit the overall plant performance. The consequences of environmental stresses on the whole plant are quite complex, dealing with structural and metabolic functions. Understanding plant responses to the external environments is of greater significance for making crops stress tolerant. One of the most deleterious effect of environmental stress on plants is oxidative stress in cells, which is characterized by the accumulation of potential harmful reactive oxygen species (ROS) in tissues. Photooxidative stress in plants is mostly induced by the absorption of excess excitation energy leading to over-reduction of the electron transport chains generating ROS. © 2006 Springer.