[Determination of the nitrogen-fixing activity of Rhizobium japonicum under sterile microvegetative conditions].

The nitrogen fixing activity of Rhizobium japonicum in symbiosis with soya grown in the sterile microvegetative conditions at an air humidity of 70%, at a temperature of 20 degrees C and a length of light day of 16 hours was assayed using the acetylene technique. The plants were cultivated in phytotron in glass tubes (245 cm3) illuminated with xenon lamps. This technique can be used, apparently, to determine the nitrogen fixing activity of other legumes and cereals.