A study on microbial population on the phyllosphere of forest plant was carried out. Both fungi and bacteria were isolated from the leaf surface of sal (Shorea robusta), teak (Tectona grandis), sissoo (Dalbergia sissoo), kosi(Bridelia Sp.), arjun (Terminalia arjuna) and sandal wood( Santalam album ) plant. Leaf washing method was adopted for isolation of the organisms although leaf impression techniques was used to assess the approximate density of microbial population. Mature leaves contain innumerable propagules in comparison to young leaves. Chromogenic bacterial colonies were abundant on both the surfaces of almost all the forest plant leaves. Total bacterial flora was quite high on the phyllosphere of plant like Teak, Sissoo and Arjun. Total bacterial count always outnumbered the fungal propagules. With regards to the density of nitrogen fixers as compared to the total bacterial population, it was revealed that Sal and Kosi leaf surfaces contained very poor number of nitrogen fixing organism among the forest plant. In Sal, out of total 280 bacterial populations, only 03 were the nitrogen fixer whereas in Teak, Arjun, sissoo and sandalwood, their numbers were high. Among the fungal population, maximum number was recorded only on teak leaves. Negligible number of fungus was recorded on the leaf surfaces of other plants. Population ratio of total bacteria/fungi was rather high on Sissoo leaf compaired to those of other leaves. Based on colony characteristics and individual cell morphology 6 strains of nitrogen fixers differentiated. All the isolates were grown at 30°C for 72 hours to see their growth performance and at the same time nitrogen fixing capacity was also observed through Acetylene Reduction Assay as well as Microkjeldahl method. In order to nitrogen fixation capability these strains can be arranged in the following order TK3>AN2>KS3>SL3>SIS1>CN2.
