Studies with detached lupin root nodules in culture: I. Maintenance and induction of acetylene reduction activity

A method has been developed for culturing detached nitrogen-fixing root nodules of lupin (Lupinus angustifolius L.) on a simple nutrient medium. Under the best conditions devised, the acetylene reduction activity of mature detached nodules was maintained at 10 to 25 nmoles of ethylene hr⁻¹ mg⁻¹ fresh weight for 3 days. Under the same culture conditions, immature nodules increased their acetylene reduction activity from 0.01 nmole or less to about 1 nmole hr⁻¹ mg⁻¹ fresh weight.