Growth and nitrogenase activity in Azolla species

Growth and nitrogenase activity were determined in thirteen collections of Azolla; eleven from A. pinnata and one each from A. mexicana and A. filiculoides. under identical condition in mineral medium. Many isolates of A. pinnata, and A. filiculoides grew better than A. mexicana and among different collections of A. pinnata, isolates of Thailand, Bangladesh and Vietnam produced more fresh and dry matter while the minimum growth was recorded in Nepal (I) isolate. Though A. mexicana showed poor growth, however, nitrogenase activity was maximum in this isolate whereas A. filiculoides showed a low level of nitrogenase activity. Among A. pinnata isolates, Bangladesh (Tangai) isolate exhibited highest nitrogenase activity and the lowest was recorded in Indonesia (Bogor) isolate.