3.7 Reactive oxygen species generation under salt in C4 species
Histochemical staining with nitroblue tetrazolium (NBT) shows the appearance of dark-blue spots on the edge of SA leaves exposed to 250 mM NaCl for 12 days (Figure 9B). This dark-blue staining reveals the interaction between NBT and the generated superoxide free radical (O-2. ) following exposure to moderately high light (500 μmol m-2 s-1). However, these dark-blue spots were spread all over the surface of SV leaves subjected to 50 mM salt for 12 days (Figure 9D), suggesting that salt treatment dramatically increased the production of reactive oxygen species (ROS) in SV . Similarly, histochemical staining using diaminobenzidine (DAB) showed no visible brown spots on either control or salt-treatedSA leaves (Figure 10A-B). In contrast, SV treated with only 50 mM NaCl for 12 days shows a widespread presence of brown spots on the leaf surface (Figure 10C-D).