CHLOROPHYLL-SENSITIZED REDUCTION OF PLASTOQUINONE BY ASCORBIC ACID AND QUENCHING OF CHLOROPHYLL-FLUORESCENCE BY PLASTOQUINONE

1. Photochemical reduction of plastoquinone by ascorbic acid inethanol was sensitized with some derivatives of chlorophyll.The order of effectiveness was as follows: allomerized chlorophylla > chlorophyllin a > chlorophyll a > chlorophyll b> pheophytin a.
2. Quenching of the fluorescence of chlorophylla by plastoquinonewas observed. The quenching constant calculatedwas 71 litreper mole.

¹Contribution No. 159 from the Department of Biology, Facultyof Science, Kyushu University. Supported in part by a grant-in-aidfor Fundamental Scientific Research from the Ministry of Education.²Present address: Biological Laboratory, General Education Department,Kyushu University, Ropponmatsu, Fukuoka.³Present address: Biological Institute, Daiichi College of PharmaceuticalSciences, Tamagawa-machi, Takamiya, Fukuoka.