The strips were then transferred to

The strips were then transferred to the opening medium containing pharmacological agents (10 mM ABA, 100 mM cPTIO, 100 mM cPTI, 1 mM NOC5, 1 mM arginine, 100 mM H2O2, 25 mM L-NAME and 25 mM D-NAME), and were kept at 23 °C under light(25 mmol m-2 s-1) for 2.5 h.
For stomatal closing, epidermal strips were floated in the opening medium under light for 2 h. The strips were then ransferred to the closing medium(10 mM MES-KOH, pH 6.15, 50 mM KCl, 10 mM ABA,0.1 mM CaCl2) containing harmacological agents, and were then kept at 23 °C under light for 1 h.After treatment,the stomata were photographed using a digital camera(Coolpix 995; Nikon Corp., Tokyo, Japan) under a microscope(Eclipse E600; Nikon Corp.).
Inner widths of stomatal pores were measured using a digital microanalyser(Japan Polaroid Digital Products, Tokyo, Japan).
At least four strips were measured in each treatment with 20 stomata in each strip. Experiments were repeated at least
three times. Student’s t-test was used to determine signifi-cant differences.