12 THE PLANT CELL WALL 



Table 1. Solubility Characteristics Of Wall Components 



Reagent 



Non- Polyuroni- 



Cellulose 



cellulosic 

 polysac- 

 charides 



de hemi- 



cellulo- 



ses 



Pectic 

 subst. 



Lignin 



Cuticle 

 subst. 



Cold dil. alkali 

 Hot. dil. alkali 

 Hot. cone, alkali 

 Hot. dil. acid 

 Cold 72% H 2 S0 4 

 Hot dil. alcoholic KOH 

 Cold cone, alkali 

 Warm dil. H 2 2 

 Warm dil. ammon. 



oxalate 

 Cuprammonium 



solution 

 Ethanolamine 

 Dioxane, phenols 

 Hot. dil. alcoholic HC1 



± 

 + 



+ 

 ± 



Partial 



A more generally useful scheme begins with the removal of 

 lignin by extraction of whole cell wall with chlorine and hot etha- 

 nolic ethanolamine solution. The residue is then treated with cold 

 4 per cent NaOH to remove the polyuronide hemicellulose, and 

 finally cold 17.5 per cent NaOH is used to separate cellulose 

 (residue) and the non-cellulosic polysaccharides. Unfortunately, 

 some loss of non-cellulosic polysaccharide also occurs in dilute 

 alkali, necessitating an additional independent determination of 

 this fraction. 



Methods such as the foregoing which have developed out of 

 wood technology do not take account of the small quantities of 

 pectic substances present in woody tissues. The pectic substances 

 may be separated independently by removal of interfering poly- 

 uronides with cold 4 per cent NaOH followed by the procedure 

 already described. 



Upon comparison of cell walls from the organs of various 

 plants, one is immediately impressed by the great differences in 



