Cytochemical localization of photosystem I in relation to differentiation of the thylakoid membranes during greening of barley leaves.
Changes in distribution of photosystem I (PS I) in the developing thylakoid membranes of greening barley (Hordeum vulgare L. cv. Amagi-Nijo) chloroplasts were studied by a cytochemical method using 3,3'-diaminobenzidine (DAB). The activity was detected on the thylakoid of etiochloroplasts after 1 h of greening. Stacks of a few thylakoids (thought to be an initiation of grana) appeared at about 2-3 h of greening. Until 4 h, the DAB reaction was observed uniformly throughout the whole thylakoid system (stroma and grana thylakoids). After 6 h of greening, The DAB reaction was detected heterogeneously in the etiochloroplasts; more intense on the stroma thylakoid and peripheral grana thylakoid. Further illumination led to more distinct heterogeneity of the DAB reaction. Thus, redistribution of PS I proceeded differentially after onset of grana formation in the developing etiochloroplasts. Measurements of chlorophyll content, light saturation of PS I activity and fluorescence emission spectra of greening barley leaves suggest that redistribution of PS I may reflect developmental changes in assembly of the PS I complex with light-harvesting chlorophyll-protein complex.
Toda
Y
Y
Department of Biology, University of Tokyo, Japan.
Murakami
S
S
D002736:Chloroplasts / Q000648:ultrastructure*; D006651:Histocytochemistry; D001467:Hordeum / Q000648:ultrastructure*; D045342:Light-Harvesting Protein Complexes; D008854:Microscopy, Electron; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000648:ultrastructure*; D045331:Photosystem I Protein Complex; D004124:p-Dimethylaminoazobenzene
D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D004124:p-Dimethylaminoazobenzene