[Fluorescence of higher plant leaves at raised temperatures]

Red fluorescence (lambda approximately 630 divided by 760 nm) of naked-spermous (Gimnospermae) plant leaves in the state of winter rest and in the summer period, and also green and etiolated angiospermous (Angiospermae) plant leaves at different developmental stages (from embryonic to mature state) was investigated in the temperature range 20-96 degrees C. At the temperature about 60 degrees C a fluorescence "flash" develops avalanche-lookingly, its intensity being the higher, the younger is the angiospermous plant leaf. In the naked-spermous plant leaves an intensive avalanche-looking process is observed only in the winter-spring period.