Simultaneous Measurement of Nitrogen Fixation Estimated by Acetylene-Ethylene Assay and Nitrate Absorption by Soybeans 1

摘要

An apparatus was designed for simultaneous measurement of rates of N2 fixation estimated by C2H2-C2H4 assay (N2[C2H2] fixation) and NO3− absorption by roots of intact, nodulated soybeans (Glycine max [L.] Merr.). The principal design features include: (a) a gas-tight mist chamber in which nodulated roots can be exposed simultaneously to C2H2 in the gas phase and to a liquid phase containing NO3− sprayed in a fine mist; and (b) provision for sampling the gas phase for C2H4 determination, and the liquid phase for NO3− determination.