Effect of arbuscular mycorrhizal (AM) fungus and plant growth promoting rhizomicroorganisms (PGPR’s) on medicinal plant Solanum viarum seedlings.

A green house nursery study was conducted to assess the interaction between arbuscular mycorrhizal (AM) fungus, Glomus aggregatum and some plant growth promoting rhizomicrooganisms (PGPR’s), Bacillus coagulans and Trichoderma harzianum, in soil and their consequent effect on growth, nutrition and content of secondary metabolities of Solanum viarum seedlings. Triple inoculation of G. aggregatum+B. coagulans+T. harzainum with Solanum viarum in a green house nursery study resulted in maximum plant biomass (plant height 105 cm and plant dry weight 12.17 g), P, Fe, Zn, Cu and Mn and secondary metabolities [total phenols (129.6 μg g-1 f.wt.), orthodihydroxy phenols (90.6 μg g-1 f.wt.), flavonoids (3.94 μg g-1 f.wt.), alkaloids (5.05 μg g-1 f.wt.), saponins (5.05 μg g-1 f.wt.) and tannins (0.324 μg g-1 f.wt.)] of S. viarum seedlings. The mycorrhizal root colonization and spore numbers in the root zone soil of the inoculated plants increased. The enzyme activity namely acid phosphatase (53.44 μg PNP g-1 soil), alkaline phosphatase (40.95 μg PNP g-1 soil) and dehydrogenase (475.5 μg PNP g-1 soil) and total population of B. coagulans (12.5×104 g-1) and T. harzianum (12.4×104 g-1), in the root zone soil was found high in the triple inoculation with G. aggregatum+B. coagulans+T. harzianum that proved to be the best microbial consortium.

Studies of VA-Mycorrhizal fungi associated with some weed plants in sugar mill effluent soils.

This study is to isolate the effluent strain of VAM fungi from polluted soils of sugar mill effluents. Analysis showed that pH and EC was more but the organic matter is less when compared to non-polluted soils. Even though there was low P content that enhances the mycorrhizal infection, the percent of root colonization was less than 75% in polluted study site. The number of VAM propagules and its distribution were also greatly affected due to various factors. Nine different VAM species were isolated and identified from the polluted study site. Using Allium cepa L. as the host plant the efficiency of the native effluent tolerant strains of VAM fungi isolated from the polluted study site was determined. Highest growth rate, high dry weight of gram per plant and increased growth was observed in the order of Glomus intraradices followed by Gigaspora margarita and Glomus fasciculatum. Consequence of the study clearly showed that Glomus intraradices was the efficient strain in sugar mill effluent polluted areas.