Determination of physical damage thresholds of strawberry leaves (Fragaria x ananassa cv. Honeoye)

Damage thresholds of strawberry plants (Fragaria x ananassa) were investigated by mechanical damage. Mechanical damage was applied by 10%, 20% and 30% of the leaf area of a fully expanded single leaf removal. Strawberry leaves that were mechanically damaged did not recover their photosynthetic capacity at any damage level. Chlorophyll fluorescence (F-v/F-m) values were not affected from the mechanical damage. Increasing damage levels decreased the ability of the strawberry leaf to use light and carbon dioxide in photosynthesis. Difference in stomatal conductance and transpiration rates were insignificant. Internal CO2 (C-i) levels were higher in damaged plants compared to the control plants.