Fig. 6
Wetting contact angles of deionized water on Prunus leaf surfaces directly after aqueous solutions of SDS, CTAB and Glucopon were sprayed to the leaf surfaces and had dried off (black bars). Wetting contact angles were again measured 24 h after the treatment (light gray bars) and on leaves where surfactant deposits had been washed off after 24 h (dark grey bars). Surfactants were sprayed leading to a coverage of 1 µg cm−2. After washing off the dried surfactants from the leaf surfaces, wetting contact angles fully recovered (grey bars) and were not different from control leaves treated with deionized water instead of surfactants (dotted black line). Differential letters indicate significant differences between the different alcohol ethoxylates and the different treatements at p < 0.05. Bars represent means with standard deviations (n = 15)