Nitrogen-fixing capacity
The nitrogen-fixing capacity of nodules was determined in vivo by
measuring the reduction of acetylene to ethylene, as previously
described as acetylene-reducing activity (Hardy et al. , 1968).
Nodulated roots were harvested and incubated at 30 °C for 1 h in
rubber-capped tubes containing a 10% acetylene atmosphere. Two
biological replicates have been performed with five technical
replicates. Ethylene concentrations were determined by gas
chromatography (Agilent GC 6890N, Agilent Technologies, Santa Clara, CA,
USA) equipped with a GS-Alumina (30 m × 0.534 mm) separating capillary
column.