The effect of inoculation with mycorrhiza: Am on growth, phenolics, tannins, phenolic composition and antioxidant activity in valeriana jatamansi jones

Abstract

The mycorrhizal inoculation often reported to increase plant growth and secondary metabolites production, however, little is known on the effect of arbuscular mycorrhizal fungi (AMF) on different growth parameters in Valeriana jatamansi, an important Himalayan medicinal herb. To evaluate mycorrhizal effect, V. jatamansi collected from natural population were planted and growth parameters, phytochemicals, antioxidant and phenylalanine ammonia lyase (PAL) activities were determined. Significantly (p<0.05) higher above ground fresh weight (AGFW), above ground dry weight (AGDW), below ground fresh weight (BGFW), below ground dry weight (BGDW) were recorded in plants after the 2nd year. The total phenolics were maximum in aerial [18.03±0.05 (1st year) and 10.88±0.52mg GAE/g (2nd year)] and root portions [(14.30±0.04 (1st year) 7.92±0.27 (2nd year)] of the treated plants as compared to corresponding portions of control plants in both the years. Similarly, the tannin content was higher in treated plants as compared to untreated controls. Variation in different phenolic compounds was also recorded and significantly higher contents of gallic acid, chlorogenic acid, Catechin, and Hydroxy benzoic acid during 1st year was observed. Antioxidant activity of aerial and root pprtion measured by three in vitro assays, showed significant variation (p<0.05) among plants of both the years. Significantly (p<0.05) higher PAL activity was recorded in treated over control plants in 2nd year. The results demonstrated that inoculation with AMF enhances both phenolics and tannins as well as stimulates antioxidant activity suggesting a positive influence of AMF inoculation on yield and for the production of nutraceuticals.