Abstract
Using absorption change at 703 nm induced by an actinic light, non-destructive estimation of P700 content, the amount of photosynthetic unit, was attempted by a flash spectrophotometer designed for the measurements of living leaf segments. The estimated P700 contents by this method agreed well with those determined by the conventional chemical method with remarkable reduction of times required for measurements. The crop leaves with higher chlorophyll a/b ratios were found to show smaller sizes of photosynthetic unit (chlorophyll/P700).
