Abstract:
The roles and mechanisms of natural and synthetic auxin IAA, NAA, 2,4-D, cytokinin ZT, KT, 6-BA in light/dark-regulated stomatal movement were investigated by means of stomatal bioassay and using laser-scanning confocal microscopy. The results showed that the effects of auxin IAA, NAA, 2,4-D, cytokinin ZT, KT, 6-BA and NO scavenger cPTIO, Hb, NOS inhibitor L-NAME, H2O2 scavenger AsA, CAT, NADPH oxidase inhibitor DPI on stomatal opening were more significant in dark than in light, suggesting that endogenous auxin, cytokinin, NO and H2O2 mediated light/dark-regulated stomatal movement, and the levels of endogenous auxin and cytokinin were more higher in light than in dark. However, The results indicated that endogenous NO and H2O2 were more greater in dark than in light. In addition, the effects of auxin and cytokinin tested on stomatal movement in light or in darkness are accordant with that of NO and H2O2 scavengers, synthetic inhibitors, the results imply that auxin and cytokinin probably promoted stomatal opening via decreasing endogenous NO and H2O2, which was verified by the monitoring results of endogenous NO, H2O2 fluorescence.
