Assessing the physiological state of woody plants by parameters of chlorophyll fluorescence in the bark of annual shoots

The relative yield of variable chlorophyll fluorescence in the bark of annu al shoots of woody plants was measured with a portable pulse modulated fluo rometer designed for this purpose at the Department of Biophysics (Biologic al Faculty, Moscow State University). Experiments were performed to study t he response of this parameter to external influences (treatment with an her bicide, water loss, etc.). The results demonstrated the possibility of reli ably recording the parameters of fluorescence in the annual shoots of vario us woody plants without damaging these shoots. It is concluded that measure ments of chlorophyll fluorescence in the bark of woody plants can be used f or analyzing changes in the physiological state of tree stands under the ef fects of natural and anthropogenic factors.