Blue-green fluorescence, UV-B and UV-A radiation, barley, plant stress

Blue-green fluorescence (BGF) is emitted by higher plant pigments when excited by UV radiation. The emission spectrum of BGF varies among plant species and depends on the physiological status of the plants (Chapelle 1984). BGF has been attributed particularly to cell-wall-bound ferulic acid, although it has been suggested that flavonoids and other simple phenols can contribute to BGF (Morales 1994). Remote sensing application techniques use ratios of BGF to chlorophyll red and far red fluorescence emission intensities to estimate plant stress (Lichtenthaler 1996). In this work we have focused on characterization of BGF response of barley leaves to different levels of photosynthetically active radiation combined with UV-A and UV-B radiation. The aim of this work is to distinguish individual fluorescent components of BGF emission. Based on different response of these components to UV-radiation we suggest fluorescence ratios appropriate for monitoring of UV plant stress.