葉緑素の光褪色に関する研究

Abstract

The photobleaching of chlorophyll which was absorbed on silica gel was examined by the irradiation of visible light (Matsuda tungsten filament lamp)under the various conditions: I. in the air with moisture. II. in N2 gas with moisture. III. in the air in dry state. IV. in N2 gas in dry state. Under the condition I, the photobleaching was observed and I2-starch test paper placed in the apparatus turned into blue, while both the photobleaching and color change of test paper was not observed at II and IV, and a little at III. The mechanism of photobleaching of chlorophyll by the irradiation with visible, light was shown as follows: Chl.+hv………………Chl.* Chl.*+O2………………Chl.+O2* O2*+H2O………………H2O2 H2O2(HO_??_)+Chl.*…oxy-Chl.+H2O *:exited molecule It was concluded that the photobleaching of chlorophyll by the irradiation of visible light was produced by the action of hydrogen-peroxide which was made from H2O and O2 at the presence of photo-exited chlorophyll. To prevent the photobleaching, catalytic decomposition of hydrogen-peroxide by Cu-chlorophyllin was examined. Chlorophyllin was absorbed on the silica gel, and then Cu-chlorphyllin was absorbed on it. Chlorophyll treated with Cu-chlorophyllin was irradiated in the presence of the air with moisture. Cu-chlorophyllin detered considerably the chlorophyll from the photobleaching by the visible light.