Translocation of Photosynthetic Products to Soybean Nodules and Their Role in Nitrogen Fixation.

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Abstract
The root and nodule tissues of soybean plants, whose tops had been exposed to Cl4O2 were examined for the distribution of C14 among their various organic acids, amino acids and carbohydrates, and for the changes occurring in this distribution when the plants were allowed to metabolize the radioactive material during a dark period following the initial light period. During this day, the organic acids of the roots had a higher percentage of the total Cl4 than did the amino acids; the reverse was true in the nodules. At night, the percentage of total Cl4 in the organic acids of the roots decreased while it increased markedly in the nodules. Several unidentified acids and sugars were found. The addition of sugars to sliced, excised soybean nodules increased their fixation of Ni. The optimal concentrations of sugar were in the range 0.005 to O.O2 [image], and glucose, fructose and sucrose had essentially the same enhancing action. The increase did not arise from a prolongation of the period of N2 fixation but rather from a continuous enhancement of fixation throughout the exposure to N5.