Kohl D H, Bryan B A, Shearer G
Biology Department, Washington University, St. Louis, Missouri 63130.
Plant Physiol. 1983 Oct;73(2):514-6. doi: 10.1104/pp.73.2.514.
Non-nodular tissue of soybean (Glycine max L. Merrill) plants grown hydroponically in the absence of added N have a (15)N abundance close to that of atmospheric N(2). In contrast, nodules are usually enriched in (15)N. In this paper, we report measurements of the (15)N abundance of foliar tissue and nodules of soybeans inoculated with 11 variably efficient strains of Rhizobum japonicum and grown hydroponically with no added N. The efficiency of the 11 symbioses varied over a wide range as judged by a 16-fold difference in N content. The degree of (15)N enrichment of nodules was closely correlated with N(2)-fixing efficiency (milligrams N fixed per milligram N in the nodules).These results confirm prior preliminary data based on six variably efficient R. japonicum strains. The strong correlation between (N)N enrichment of soybean nodules and N(2)-fixing efficiency is consistent with the hypothesis that new nodule tissue is synthesized from a pool of recently fixed N within the same nodule.
在不添加氮的情况下水培生长的大豆（Glycine max L. Merrill）植株的非根瘤组织，其（15）N丰度接近大气N₂的（15）N丰度。相比之下，根瘤通常富含（15）N。在本文中，我们报告了对接种11种固氮效率各异的日本根瘤菌菌株且在不添加氮的情况下水培生长的大豆叶片组织和根瘤的（15）N丰度的测量结果。根据氮含量16倍的差异判断，这11种共生关系的效率在很宽的范围内变化。根瘤的（15）N富集程度与固氮效率（每毫克根瘤中固定的氮毫克数）密切相关。这些结果证实了基于六种固氮效率各异的日本根瘤菌菌株的先前初步数据。大豆根瘤的（15）N富集与固氮效率之间的强相关性与新根瘤组织由同一根瘤内最近固定的氮库合成的假设一致。
