Table IV.

Diameters of stomatal pores (including walls of guard cells), measured at their midpoints, in epidermal peels of tobacco leaves untreated (control) or treated with 0.02 mm ABA alone (ABA), 0.02 mm ABA ⁺ 0.01 mm NAE12:0 (ABA ⁺ NAE), or 0.02 mm ABA ⁺ 0.01 mm lauric acid (ABA ⁺ free fatty acid [FFA]) for 20 and 40 min

Treatment	Mean Pore Diameter in Micrometers (se)
	20 min	40 min
Control (0.067% [v/v] DMSO)	9.20 (0.17), n = 97	8.99 (0.17), n = 102
ABA	8.40 (0.18), n = 99	8.07 (0.17), n = 104
ABA + NAE	9.30 (0.17), n = 95	9.10 (0.16), n = 112
ABA + FFA	8.53 (0.20), n = 97	8.18 (0.16), n = 115

Stomates were induced to open by incubation of epidermal peels floated on 5 mM MES NaOH (pH 6.1), 22 mm KCl, and 1 mm CaCl₂ for 2 h under white light (125 μm m⁻² s⁻¹) prior to treatments (see “Materials and Methods”). Measurements were made with between 90 and 115 guard cell pairs for each treatment. At time zero, average diameters of stomatal pores were 8.99 ± 0.17 μm. After incubation for 2 h in the dark, these stomates measured 7.00 ± 0.12 μm. Data represent mean and se from a single representative experiment. Replicate experiments showed identical trends. Comparisons by t test: Control versus ABA, P < 0.001; ABA versus ABA ⁺ NAE, P < 0.001; ABA versus ABA ⁺ FFA, P > 0.4.