Compartment specific changes of the antioxidative status in Arabidopsis thaliana during salt stress

The compartment specific importance of ascorbate and glutathione was investigated during salt stress in Arabidopsis Col-0 and mutants deficient in ascorbate and glutathione (vtc2-1, pad2-1). This study demonstrated that higher sensitivity of the vtc2-1 mutants which showed leaf necrosis and lower biomass at the beginning of the salt stress experiment was correlated with lower basal ascorbate contents and a decrease in ascorbate contents in mitochondria (67%), peroxisomes (68%) and the cytosol (38%). Higher tolerance of pad2-1 mutants to salt stress throughout the first 10 days of the experiment could be correlated to a massive increase of glutathione contents (up to 740% in nuclei) in all cell compartments. A similar situation was found for wildtype plants which showed higher tolerance to salt stress at the beginning of the experiment which could be correlated with a strong increase of glutathione contents in mitochondria (39%), chloroplasts (up to 26%) and peroxisomes (up to 84%) indicating an important role of glutathione in the protection of these cell compartments against salt stress. Summing up, the results demonstrate that higher tolerance to salt stress of wildtype plants and pad2-1 mutants at the beginning of the experiment could be correlated to increased glutathione contents which could not be found in vtc2-1 mutants which in addition showed lower ascorbate contents and higher sensitivity to salt stress.