SEED POLYSACCHARIDES AND THEIR ROLE IN GERMINATION. A SURVEY OF THE POLYSACCHARIDE COMPONENTS OF MUSTARD SEEDS WITH SPECIAL REFERENCE TO THE EMBRYOS.

1. Methods were developed for the extraction, fractionation and purification of the more soluble polysaccharides of mustard-seed embryos. 2. One of these components was a pure homopolysaccharide, an araban, which was characterized by analysis, optical rotation, chromatography on diethylaminoethylcellulose and electrophoresis; the hydrolysis products of the methylated polysaccharide were isolated and characterized by the formation of crystalline derivatives. From these studies it emerges that mustard-seed araban is very similar to the family of pectic arabans, except that it is more highly branched than usual and contains a proportion of 1-->2-linkages. 3. A survey of the other polysaccharides of mustard seed, both in the embryos and in the seed coats, suggests a predominance of pectic-type polysaccharides.