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The rate of transport through a phosphate translocator affects delayed luminescence induction: an experiment and a theoretical model
Author(s) -
KHUZNETSOVA S,
BOGRACHEVA T,
HEDLEY C,
TULESHOVA A,
KUKUSHKIN A
Publication year - 2001
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.2001.tb00092.x
Subject(s) - biology , mutant , pi , phosphate , starch , cytosol , biochemistry , chloroplast , wild type , photosynthesis , biophysics , gene , microbiology and biotechnology , botany , enzyme
Summary Delayed luminescence (DL) induction curves were studied in leaves from a mutant pea line containing mutations at both the r and rb loci, compared with leaves from wild type plants. Genes at the r and rb loci encode starch branching enzyme and ADP ‐ glucose pyrophosphorylase, respectively. The presence of mutations at both loci, previously known to reduce the starch content in the dry mature seed by 75%, have been shown to lower the starch level in leaves by at least 20%. During induction, the half‐time for the DL intensity decrease from maximum to steady state in the mutant was 1.5 ± 0.2 times longer than for the wild type. It is proposed that the prolongation of the induction period in leaves from the mutant plants is caused by a lack of inorganic phosphate (Pi) restricting the rate of ATP synthesis at the beginning of induction. The reduced Pi would be compensated by triose flow from the chloroplast, via the triose phosphate translocator, being exchanged for Pi from the cytosol. Analysis of our theoretical photosynthesis model confirmed that a decrease in the rate of Pi released from the Calvin cycle could lead to a prolongation of the induction period.