ISSN:
1573-5079
Keywords:
biosynthesis of pheophytin a and chlorophyll a
;
etiolated leaves
;
Photosystem II
;
reaction centres
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Illumination of etiolated maize leaves with low-intensity light produces a chlorophyll/pheophytin-containing complex. The complex contains two native chlorophyll forms Chl 671/668 and Chl 675/668 as well as pheophytin Pheo 679/675 (with chlorophyll/pheophytin ratio of 2/1). The complex is formed in the course of two successive reactions: reaction of protochlorophyllide Pchlde 655/650 photoreduction resulted in chlorophyllide Chlde 684/676 formation, and the subsequent dark reaction of Chlde 684/676 involving Mg substitution by H2 in pigment chromophore and pigment esterification by phytol. Out data show that the reaction leading to chlorophyll/pheophytin-containing complex formation is not destructive. The reaction is in fact biosynthetic, and is competitive with the known reactions of biosynthesis of the bulk of chlorophyll molecules. The relationship between chlorophyll and pheophytin biosynthesis reactions is controlled by temperature, light intensity and exposure duration. The native complex containing pheophytin a and chlorophyll a is supposed to be a direct precursor of the PS II reaction centre in plant leaves.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00019055
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