RELATIONSHIP BETWEEN THE LIFETIME AND YIELD OF THE 735 NM FLUORESCENCE OF CHLOROPLASTS AT LOW-TEMPERATURES

The lifetime and relative yield of the 735 nm fluorescence of [pea] chloroplasts, over a range of low temperatures (-60 to -196.degree. C) where the yield of fluorescence changes markedly, were directly proportional. Apparently 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. Attempts to measure the rise-time of the 735 nm fluorescence at -196.degree. C indicated that the rise-time is less than 50 ps.