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Fig. 13.9 MV Chlide b biosynthesis via routes 2, 4 and 5 in DDV-LDV-LDDV plant species at
the beginning of illumination of etiolated plant species (Adapted from Fig. 6.3 of Chap. 6 )
Biosynthesis of MV Chl b from MV Chl a via Route 8 in Greening DDV-LDV-LDDV
Plants During the Light Phases of the Photoperiod
Most of the MV Chl b accumulation in DDV-LDV-LDDV plants takes place during
the light phases of the photoperiod. In route 8, MV Chl b is formed from MV Chl
a which is formed in turn from DV Chlide a and MV Chlide a (Fig. 13.11 ). In this
case too, conversion of MV Chl a to MV Chl b is supported by favorable precursor
product relationship between MV Chl a and MV Chl b after 7 and 8 h of illumina-
tion of DDV-LDV-LDDV plant tissues (Rebeiz et al. 1999 ).
Since under continuous illumination, most of the synthesized Chl consists of MV
Chl a , and b located in antenna Chl-protein complexes, (Akoyunoglou 1978 ;
Akoyunoglou et al. 1981 ; Alberte et al. 1972 ), we propose that the MV Chl
b formed via route 8 is destined to LHCII and other outer antenna Chl-protein
complexes.
It is presently acknowledged that under certain conditions, MVChl b is converted
to MV Chl a in green cucumber cotyledons (Ohtsuka et al. 1996 ). These authors
proposed that during the light phase of the photoperiod, the photosynthetic
apparatus is reorganized during acclimation to various light environments. This
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