Fig. 6.

Surface wettability or hydrophobicity of abaxial and adaxial leaflet sides determined as the contact angle of a water droplet (A) and leaflet gas film thickness upon initial submergence in water (B) of 15 accessions of 28-day-old plants of Melilotus siculus grown in aerated nutrient solution. In (C) is shown the curvilinear relationship between the leaf gas film thickness and the mean contact angle (averaged for both leaflet sides) as described by a fitted quadratic equation. The leaf lamina gas film thickness (i.e. height of the gas layer adjacent to the leaflet surface) was calculated from the total gas film volume for both sides and the two-sided surface area for the three leaflets of the youngest fully expanded leaf of each plant. Values are means ± s.e. of four replicates. In (A), the significance of the effects of the main factors (‘accession’ and ‘leaflet side’) and the interaction of a two-way ANOVA is shown. In (B), different letters above bars indicate differences among accessions based on Tukey test (P < 0.05).