Excretion of Nitrogen Compounds by some Legumes Grown in Sand Culture 1

ONSIDERABLE work was done on excretien of nitrogen comC pounds from legume roots prior to the extensive studies of Virtanen ( s ) ~ and associates of the Biochemical Institute, Helsinki, Finland. Excretion of these nitrogen compounds occurs erratically and some of the early work probably was not published because replications did not agree within the limits thought necessary for scientific standards of reproducibility. Principal credit for establishing proof and bringing about general acceptance of the excretion of nitrogen compounds from legume roots, however, goes to the Finnish workers. The Helsinki findings have not been widely confirmed, but this is understandable because the factors governing the process are complex, not fully known, and may vary a t different geographic locations and under different environmental conditions. Comprehensive reviews by Wilson (7) and by Burk and Burris (2) and the discussion by Wyss and Wilson (9) make further reference t o the literature unnecessary. The object of the work reported in this paper was to demonstrate nitrogen excretion and endeavor to learn more with regard to the conditions controlling the phenomenon. Such knowledge is fundamental to adequate study of the excreted nitrogen compounds and of the mechanism of the process. The biochemical study of fixed excretion intermediates already has contributed materially to our knowledge of symbiotic nitrogen fixation (6).