The relationship between the lifetime and yield of the 735 nm fluorescence of chloroplasts at low temperatures.

ABSTRACT

The lifetime and relative yield of the 735 nm fluorescence of chloroplasts, over a range of low temperatures (-60 to -196 degrees C) where the yield of fluorescence changes markedly, were found to be directly proportional. It is concluded that the species of chlorophyll responsible for the 735 nm fluorescence, C-705, is present over the entire temperature range but is less fluorescent at the higher temperatures because of greater energy transfer to P-700. It is also concluded from attempts to measure the rise-time of the 735 nm fluorescence at -196 degrees C that the rise-time is less than 50 ps.