XVI International Botanical Congess

Alnus nepalensis is a multipurpose large deciduous tree found in subtropical to cool temperate climate throughout the Himalayas from Kashmir to Burma at 600-3000 m (Lamechhaney,1984). In Nepal it is widely spread between 1000 to 3000 m in middle mountains preferring stream beds, wet ravines and recently eroded sites. It is best known nodulated non legume and nodules are to fix 814 mg N/g nodule dry wt./yr. as against 539 mg N/g nodule dry wt./ yr. fixed by peas (Ambasht & Sharma,1981).The nitrogen fixing efficiency and nodulation parameters studied, sample collected from various ecological zones of Nepal. The nodule number ,size of nodules and their dry weight are not the same, there is significant variation. The nitrogenase activity was measured using Gas Chromatograph and we observed variation in the samples collected from various experimental sites. The data collected on the basis of morphological characters e.g. DBH, number of seeds per flower, size of seed and mitotic index.