Positive growth responses of the medicinal plants Spilanthes calva and Withania somnifera to inoculation by Piriformospora indica in a field trial.

The medicinal plants Spilanthes calva and Withania somnifera were inoculated with Piriformospora indica, a plant growth-promoting root endophyte, in nurseries and subsequently transferred to the field. A significant increase in growth and yield of both plant species was recorded relative to uninoculated controls. Shoot and root length, biomass, basal stem, leaf area, overall size, number of inflorescences and flowers and seed production were all enhanced in the presence of the fungus. Net primary productivity was also higher than in control plants. The results clearly indicate the commercial potential of P. indica for large-scale cultivation of S. calva and W. somnifera.