Abstract:
The role of carbon monoxide (CO) in light/dark-regulated stomatal movement in Vicia faba and interrelationship between CO and nitric oxide (NO), hydrogen peroxide (H2O2) were investigated by epidermal strip bioassay. Results showed that CO donor Hematin (Ht) promoted stomatal closure significantly in light, but did not in darkness. ZnPPⅨ, a specific synthetic inhibitor of CO, accelerated stomatal opening obviously in darkness, but did not in light. The results indicate light/dark regulate stomatal movement through adjusting the level of CO in guard cells. In addition, NO donor SNP- and H2O2-induced stomatal closure was distinctly reversed by ZnPPⅨ, and Ht-induced stomatal closure was significantly prevented by cPTIO, L-NAME, Vc, CAT and DPI, which is a scavenger of NO, a specific inhibitor of NO synthase (NOS), a scavenger of H2O2, an H2O2 scavenging enzyme and an inhibitor of H2O2-generating enzyme NADPH oxidase respectively. These data provide evidence that CO induced stomatal closure via elevating the content of NO and H2O2 in guard cells, and NO, H2O2 promoted stomatal closure through increasing the CO level of guard cells during light/dark-regulated stomata movement.
