Fig. 4.

Inhibition by tungstate (Tug) or NG-nitro-l-arginine methyl ester (L-NAME) of NO production stimulated by 2R,3R-butanediol (2,3-B). Epidermal cells in a leaf peel were incubated with DAF2-DA in MES buffer for 2 h prior to exposure to 100 μM 2R,3R-butanediol (2,3-B) in the absence or presence of L-NAME (200 μM) or tug (100 μM). Fluorescence was measured using a confocal microscope, and data are displayed as mean pixel intensities and associated standard deviations. A total of 50–100 guard cells were observed per treatment of three independent replicates. Different letters indicate significant difference between treatments according to the least significant differences test at P < 0.05.