112 Botanical Microtechnique 



Fig. 1 1 .li— C;oinj);ii isoii ol lixalion in alfalfa stems: a, good fixation with C.raf 0.20- 

 1.0-10.0, dioxan process; b, plasmolyzcd cells in cortical region, Craf 0.30-1.0-10.0, 

 acetonc-7!-biitvl alcohol process; c, good fixation, hnt with peeling epidermis. ])rocess 



as in a. 



plasts are appre.ssed aj^aiiist the cell wall, iiulitatin^ ahsciue ol 

 jilasmolysis. The physical ajjpearaiuf ol these cells may be regarded 

 as approximating the stnuiurf ol li\ing ttlls. ()bser\e liiiilur that 

 the epidermis is not |)eeled a\\;i\ liotii the iiiiui tissues. These features 

 ai( iiidicati\e ol siiccesslid processing. 



in comparison -with tlu' ;il)ove case, examine Fig. 11.2/^ also a 

 cross section ol allaUa stem, killed in FAA and carried through an 

 alcohol-xylene series. Ihere is marked plasmolysis; tlu- massed chloro- 

 plasts and cytoplasm absorb the stain and cannot be destained diller- 



