Quantitative analysis of transport of fixed nitrogen from soybean nodule using N as a tracer

Hung, N. V. P.; Watanabe, Shiori*; Ishikawa, Shinji*; Otake, Norikuni*; Sueyoshi, Kuni*; Ishii, Satomi; Fujimaki, Shu; Oyama, Takuji*; Yashima, Hiroyuki*

Biological Nitrogen Fixation (BNF) plays an important role in the plant life especial in legume species. Through symbiotic fixation process, legume plants can use atmospheric nitrogen as nutritional source for their growth and development. Soybean plants have an ability to fix dinitrogen (N) in the atmosphere in root nodules and absorb nitrogen either from fertilizer or soil N. Soybean needs a large amount of N to synthesize seed storage protein especial in stage of pod filling. Many studies have been carried out in the fields of BNF, but up to now the accurate measurement of transport rate of fixed N has not determined yet. Until now, there are many methods to investigate nitrogen fixation and transportation in leguminous plants. This study used N isotope as a tracer to quantify nitrogen fixation and the transport rate of fixed N to various parts of shoots and roots in nodulated soybean plants during relatively short time from 1 h to 8h.