CARBOHYDRATE POOLS IN NODULES OF NONNODULATING AND SUPERNODULATING SOYBEAN (GLYCINE-MAX L MERR, CV BRAGG) MUTANTS

Nodulation mutants of soybean (G. max L. Merr.) forming less (nod 49, nod 139) or more (nts 382, nts 1116) nodules than the corresponding wildtype (cv. Bragg) were infected with Bradyrhizobium japonicum 61-A-101 and grown in sterilized Leonard jars under optimal phytotron conditions. After 1 month, the nodules were harvested and their carbohydrate pools were analyzed. The pools of pinitol, sucrose and starch were greatly increased in the nodules of the weakly nodulating mutants nod 49 and nod 139 as compared with the wildtype. The amount of the disaccharid trehalose, produced by the microsymbiont, was more than 50% lower in nodules from both weakly nodulating and supernodulating plants in comparison to the wildtype, The activity of trehalase, an enzyme stimulated in nodules, was about 60% lower in nodules of the supernodulating mutant nts 382 than in nodules of the isogenic wildtype.