Fig. 3.
Endogenous chemical signals in plants involving H2S, NO and ROS. N2O3 is synthesized by NO and O2 accumulated in the bilayer of cell membrane, and then forms HSNO with H2S. Extracellularly, HSNO can be directly synthesized by H2S and NO. HSNO can enhance the membrane permeability of H2S and NO, which is also the transmembrane transfer mode of cysteine thiols. Intracellularly, H2S undergoes oxidation and generates sulfate (SO42−), sulfite (SO32−), thiosulfate (S2O32−), persulfides (RSS−), organic (RSSnSR), inorganic (H2Sn) polysulfides, and elemental sulfur (Sn), which is controlled by different ratios of H2S and ROS level