Impact of the arbuscular mycorrhizal fungal inoculation on growth and biochemical parameters in Rosmarinus officinalis and Lavandula angustifolia

Beneficial microorganisms, such as mycorrhizal fungi, rhizobia, endophytes, and plant growth-promoting bacteria, can positively affect plant fitness. Particularly, mycorrhizal fungi improve plant health acquiring more nutrients and enhancing the tolerance to abiotic and biotic stresses, in return for carbon compounds. In addition, inoculation with arbuscular mycorrhizal fungi (AMF) can lead to a variation in the production of plant specialized metabolites such as polyphenols. The aim of this work was to study if the inoculations with diverse commercial AM fungal inocula can affect morphometric parameters as well as the production of polyphenols and biochemical compounds, focusing on rosemary and lavender. Although responses were variable among the treatments, it is worth noting an increase in the root dry weight of rosemary and in the height of lavender after inoculation, with differences among the two inocula. Polyphenols and the examined biochemical markers changed in relation to the used inocula. Overall, results suggested that AMF may potentially act as priming agents by inducing biochemical defence markers.