Abstract
When the heterogeneous protochlorophyll(ide) [Pchl(ide)] pool of etiolated cucumber cotyledons was converted into a chlorophyll(ide) [Chl(ide)] α pool by a very brief illumination, two red shifted Chlides, with an emission maximum at 675 nm in ether at 77K and Soret excitation maxima at about 459 and 449 nm respectively, were formed. Likewise two red shifted Chlorophylls (Chls) with an emission maximum at about 673 nm in ether at 77K, and Soret excitation maxima at about 458 and 448 nm respectively were also formed. It is suggested that Chlide α (E459F675) and Chlide α (E449F675) where E refers to the Soret excitation maximum and F to the red emission maximum in ether at 77K are identifiable with divinyl (DV) and monovinyl (MV) Chlide respectively and probably represent the first detectable photoproducts of Pchlide photoreduction. Likewise it is suggested that Chl
a (E458F673) and Chl
a (E448F673) are identifiable with DV and MV Chl
a respectively and probably represent the first detectable photoproducts of Pchlide ester photoreduction. These Chl(ide)
a intermediates appear to be converted during subsequent reactions into the blue shifted Chl
a chromophoric species that constitute the Chl
a pool of green plants.