THE PRESENCE OF TWO LIGHT-DEPENDENT ENZYMATIC PROCESSES ACCOMPANYING FLUORESCENCE DECAY IN WHEAT LEAVES DURING PHOTOSYNTHESIS.
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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The leaves of wheat sprouts Agricultural University variety 183 were used as the object of experimentation, and the variation of the time curve of chlorophyll fluorescence during the initial period of illumination was determined. Under the influence of various temperatures, fluorescence decay was found to be hastened by increasing temperatures within a definite range in addition, there was the phenomenon of a later fluorescence intensity increase known as the second rise. The occurrence of the second rise has a definite relation to temperature fluorescence decay disappears after a 10-minute treatment at a temperature of 45C after decay, leaves can recover fluorescence intensity in darkness, the degree of restoration being directly proportional to the period of time in darkness. The following results were obtained from the inhibitor experiments sodium azide, potassium cyanide and DNP have little effect on the first rise, but an inhibitory effect on the second rise malonate greatly affects the decrease of the first rise, but altogether lacks inhibitive effect on the second rise succinate and fumarate have a restoring effect on the inhibition by malonate. It is possible that the decrease of the first rise has a definite relation ot the tricarboxylic acid cycle, whereas the second rise may have something to do with the cellular pigmentation system and phosphorylation. Author