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EFFECT OF CONTINUOUS FAR‐RED PREIRRADIATION ON THE LAG PHASE OF CHLOROPHYLL A ACCUMULATION IN PHARBITIS NIL COTYLEDONS
Author(s) -
Yoshida Kazuichi,
Konishi Michio
Publication year - 1983
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1983.tb04437.x
Subject(s) - pharbitis nil , lag , lag time , phase (matter) , irradiation , chlorophyll , phytochrome , chemistry , biophysics , biochemistry , biology , botany , red light , organic chemistry , computer network , physics , computer science , nuclear physics , biological system
In Pharbitis nil cotyledons, the lag phase of chlorophyll a (Chi a) accumulation which continues for about 2 h after the onset of continuous white light is eliminated by preirradiation with far‐red light (FR) for 24 or 48 h. When the period of FR preirradiation is prolonged to 72 h or more, however, the lag phase is observed again (FR‐induced lag phase) and the rate of Chi a accumulation during the rapid accumulation phase is lowered below the dark control level. The application of exogenous 5‐aminolevulinate (J‐ALA) completely eliminates the FR‐induced lag phase, but this treatment eliminates the normal lag phase in dark‐grown cotyledons only partially (i.e. Chi a is accumulated but only slowly during the first few h). Application of a 5‐ALA precursor, such as glycin + succinate. 2‐ketoglutarate or glutamate, eliminates neither the FR‐induced lag phase nor the normal lag phase. A 24‐ or 48‐h FR irradiation seems not only to enable the synthesis of 5‐ALA but also to make the other regulatory factors favourable for Chi accumulation. When the period of FR irradiation is prolonged to 72 h or more, the ability to synthesize 5‐ALA may be lost.