Regulation of broad bean abaxial and adaxial stomatal movement by light/dark was compared. The results indicate that both abaxial and adaxial stomatal movement regulated by light/dark are related to the changes in H2O2，NO，Ca2+，mitogen-activated protein kinase kinase (MAPKK)，calcium-dependent protein kinase (CDPK) and protein tyrosine-phosphatases (PTP) in guard cells. The abaxial stomata are more sensitive to light/dark condition, and the levels of H2O2，NO，Ca2+， CDPK and PTP in abaxial guard cells are higher than that in adaxial guard cells in darkness. Additionally, the effect of Ca2+ release from intracellular store on dark-induced increase of Ca2+ levels in abaxial guard cells is more significant than in adaxial guard cells.

abaxial and adaxial epidermal; stomatal movement; light/dark; response