Effects of exogenous nitrogen-compounds on the concentrations of allantoin and various constituents in several organs of soybean plants

The effects of nitrogen compounds supplied to culture solutionson the concentrations of allantoin and various constituentsin several organs of soybean plants A62-1 (nodulating variety)were studied to elucidate the symbiotic relation. A62-1 plantsbearing well developed nodules accumulated a large quantityof allantoin in the upper stems, roots, developing leaves, podsand maturing seeds in the reproductive stage. However, the additionof N lowered the allantoin accumulation without changing thesoluble Kjeldahl-N concentration in any organs of the host plants.Also addition of N increased the amino-N concentration in upperstems and roots in contrast with the lack of change in developingleaves, pods and maturing seeds. The decrease of allantoin accumulationwas parallel with the weakened formation of nodules. The additionof N also scarcely affected the concentrations of reducing sugarand sugar in the upper stems. There were few differences inthe concentrations of allantoin, amino-N and soluble Kjeldahl-Namong nodules attached to the A62-1 plants grown in variousamounts of nitrate. Statistical calculations showed that the allantoin concentrationin A62-1 plants was correlated negatively with N applicationand positively with nodule weights. Significant levels of bothcorrelation coefficients were attained in the reproductive stage.Thevariation in allantoin concentration in A62-1 plants was notcorrelated with that in the sugar/soluble Kjeldahl-N ratio andthe reducing sugar/soluble Kjeldahl-N ratio. A large quantity of nitrate added to the nutrient solutionsof the A62-2 (non-nodulating variety) plants elicited only asmall amount of allantoin accumulation in the upper stems, witha consequent increase in the concentrations of amino-N and solubleKjeldahl-N and a decrease in the concentrations of sugar andreducing sugar. (Received August 25, 1976; )