Luminescence characteristics of strawberry leaves at early stages of injury by spider mite.

In this work, we have investigated how the luminescence characteristics and the total content of antioxidants in leaves of strawberry ( Fragaria × ananassa Duch.) change after infestation of plants by spider mites ( Tetranychus atlanticus McGregor). At early stages of plant injury, the chlorophyll concentration remained unchanged. However, the total amount of antioxidants decreased and the intensity of high-temperature thermoluminescence band (60-100°C) increased, indicating degradation of membrane lipids caused by oxidative stress. In infested leaves, the light-induced rise of nonphotochemical quenching of chlorophyll fluorescence was slower, while the relaxation of nonphotochemical quenching in the dark was faster than in control leaf samples. These data may indicate that the thylakoid membranes in infested leaves were more permeable to ions than in control leaves. [ABSTRACT FROM AUTHOR]