Figure 2. A. Effect of various physiological treatments on NO distribution in protoplasts isolated from the hypocotyls of 4 d old, light grown seedlings. (A−D) represent control protoplasts, (E−H) are treated with auxin (10 µM IAA). (I−L) are treated with auxin influx inhibitor (10 µM NPA) and (M−P) are treated with NO donor (100 µM SNP). After incubation in each treatment for 30 min, NO was localized using 25 µM MNIP-Cu and visualized at ex. 365 nm (em. 420 nm) (B, F, J and N). Co-incubation with 1 mM PTIO (D, H, L and P) confirmed the fluorescence due to NO. All the observations were taken at 630×. B. Relative fluorescence units data from protoplasts subjected to MNIP-Cu treatment for NO localization. Each datum represents mean value and standard errors from ten protoplasts subjected to a particular treatment.