22 



THE PLANT CELL WALL 



-6 galactose 1—6 galactose 1 



3 3 



1 1 



galactose 6—1 galactose 6—1 galactose 6 



3 3 



I I 



1 1 



galactose 6—1 arabinose 



3 



1 



galactose 6—1 galactose 



This polymer may be accompanied by a branched galactan, 

 molecular weight 100,000 containing (3-1,3 linkages. 



A branched corn cob polymer of molecular weight 13,700 

 contains 10.6 per cent L-arabinose with 89.4 per cent D-xylose 

 and has been formulated as: 



xylose 1—4 xylose — 4 xylose 4 xylose 1- 

 3 3 3 



1 1 



arabinose arabinose 



2 



1 

 arabinose 



2 



1 

 arabinose 



1 

 xylose 



The glucomannans of conifers appear to be [3-1,4-linked linear 

 polymers ranging from 70 to 140 in degree of polymerization. 



Still a different linkage system may be found in the arabans 

 commonly isolated from pectin preparations. Both apple and 

 peanut yield a branched arabinose homopolymer which may be 

 formulated as: 



