SO2诱导拟南芥气孔运动

Effects of SO2 derivatives on stomatal movements were investigated in model plant Arabidopsis thaliana. In the experiment, test epidermal strips were incubated in the mixture of 10mmol.L-1 MES buffer and various chemicals, the stomatal aperture was defined as the maximal width between the inner cuticular lips and detected by microscopy in living guard cells. Stomatal aperture decreased significantly when epidermal strips were incubated in the mixture of MES buffer and SO2 derivatives (mixture of sodium sulfite and sodium bisulfite-3:1, μmol.L-1/μmol.L-1) at concentrations of 7.5~150μmol.L-1. However, stomatal aperture increased significantly when epidermal strips were incubated in the mixture of 150μmol.L-1 SO2 derivatives and 1mmol.L-1ascorbic acid (AsA) or EGTA (chelator of Ca2+). Stomatal aperture decreased when epidermal strips were incubated in a solution containing MES buffer and H2O2 (0.1~10μmol.L-1) or CaCl2 (10~200μmol.L-1)，but stomatal aperture increased when epidermal strips were floated in a solution containing 10μmol.L-1 H2O2 and 1mmol.L-1EGTA. Thus, it indicated that the stimulation of calcium messenger system and accumulation of active oxygen free radical were closely related to stomatal movements induced by SO2 derivatives. The results of our present study suggested that SO2 derivatives regulate stomatal aperture through inducing reactive oxygen species (ROS) generation and activating calcium messenger system, resulting in increased plant tolerance to SO2 stress.