[Luminescence characteristics of strawberry leaves in early stages of their injury by arachnoidal mite].

In this work, we have investigated how the luminescence characteristics and a total content of antioxidants in leaves of strawberry (Fragaria x ananassa Duch.) change after infestation of plants by spider mite (Tetranychus atlanticus McGregor). At the earlier stage of plant injury, the chlorophyll concentration remained unchanged. However, the total amount of antioxidants decreased and the intensity of high-temperature band (60 divided by 100 degrees C) of thermoluminescence increased, indicating a degradation of membrane lipids caused by oxidative stress. In infected leaves, the light-induced rise of non-photochemical quenching of chlorophyll fluorescence was slower, while the relaxation of non-photochemical quenching in the dark was faster than in control samples of leaves. These data might indicate that the thylakoid membranes in infested leaves were more permeable for ions than in control leaves.