Influence of different AM-fungi on the growth, nutrition and forskolin content of Coleus forskohlii

A glasshouse investigation was conducted to study the effectiveness of 11 arbuscular mycorrhizal (AM) fungi on the medicinal plant Coleus forskohlii. Coleus plants raised in presence of most of the AM fungi in polythene bags showed an increase in plant growth (height, number of branches and biomass), P, and forskolin contents over those grown in the absence of soil inoculation with AM fungi. The extent of growth, P, and forskolin status varied with the AM fungi used. Based on the plant biomass, P uptake and forskolin content per plant, Glomus bagyarajii was found to be the best AM symbiont for inoculating C. forskohlii, the next being Scutellospora calospora.