Role of Inducible-NOS in Light/Darkness-Regulated Stomatal Movement of Vicia Faba

In this study,the abaxial epidermis of Vicia faba is used as materials,and role of NO in light/dark-regulated stomatal movement is investigated by epidermal strip bioassay,immunocytochemical methods,carbolfuchsin staining and laserscanning confocal microscopy(LSCM).Our data shows that the darkness-induced stomata closure and NO generation in guard cell can be prevented by 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide(cPTIO) and NG-nitro-L-Arg-methyl ester(L-NAME),the specific NO scavenger and an inhibitor of NO synthase(NOS) respectively,which has no significant effect on stomatal aperture in light.So we suggest that light/darkness-regulated stomatal movement is related to the levels of NO in guard cell.In addition,we also indicate that in nucleus of V.faba guard cells plant possess inducible-nitric oxide synthase(iNOS),and light/darkness-regulated NO levels in guard cells of Vicia faba is likely related to the change of iNOS activeness,and then results in the opening or closing of the stomata.