Assessing the effect of solar radiation on plant salt tolerance as defined by the static and dynamic indices

Any interaction between plant salt tolerance and environment is critical to crop breeders, geneticists, molecular biologists, soil-water-crop modelers and all researchers interested in 'global change'. A common criterion used for plant salt tolerance is a threshold value of root zone salinity, a static index that delimits the onset of yield reduction. According to this criterion, it was discovered that tomato salt tolerance decreases significantly with reduced solar radiation. In contrast, the threshold values of a new index based on the dynamic processes of salt accumulation relative to growth, are invariant to solar radiation. The variability and stability of the respective indices provides new insights for accessing physical and biochemical processes governing plant response in saline environments.