insights into the significance of antioxidative defenseunder salt stress

Salt tolerance is a complex trait involving the coordinated action

of many gene families that perform a variety of functions

such as control of water loss through stomata, ion sequestration,

metabolic adjustment, osmotic adjustment and antioxidative

defense. In spite of the large number of publications on

the role of antioxidative defense under salt stress, the relative

importance of this process to overall plant salt tolerance is still

a matter of controversy. In this article, the generation and scavenging

of reactive oxygen species (ROS) under normal and salt

stress conditions in relation to the type of photosynthesis is

discussed. The CO2 concentrating mechanism in C4 and CAM

plants is expected to contribute to decreasing ROS generation.

However, the available data supports this hypothesis in CAM

but not in C4 plants. We discuss the specific roles of enzymatic

and non enzymatic antioxidants in relation to the oxidative load

in the context of whole plant salt tolerance. The possible preventive

antioxidative mechanisms are also discussed.