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CHLOROPLASTS, CHROMOPLASTS AND CHROMATOPLASM CHAP. 37A 



tain pharmaoeutioal preparations), cannot be recognized in vivo, but the 

 columnar arrangement of the grana in living chloroplasts is clearly visible 

 in side view. Large starch grains sometimes push the grana-carrying 

 layers apart, thus disrupting the columns (fig. 37A.1). 



Fig. 37A.1. Microscopic view of the chlorojjlasts ot Oleconiu hecler- 

 acea from the top (at left) and from the side (at right), showing starch 

 bodies pushing apart layers of grana and thus intei-rupting their colum- 

 nar arrangement (after Strugger 1951). 



Fig. 37A.2. Chloroplast model, showing grana arranged in 

 layers and supported by thin, colorless lamellae. Grana in all 

 layers from vertical columns (after Strugger 1951). 



Strugger made experiments on chloroplast fixation, and confirmed earlier 

 findings (Meyer, Heitz) that 2% Os04 is a satisfactory reagent for the 

 preservation of chloroplast structure (better than picric acid and other 

 commonly used fixatives). Such jellied preparations could not be stained 



