Bioprospecting of lemon balm (<i>Melissa officinalis</i> L.) inoculated with mycorrhiza under different rates of phosphorus for sustainable essential oil production

Abstract

<abstract> <p>This study aimed to evaluate the yield and chemical composition of essential oil (EO) and the growth parameters of <italic>Melissa officinalis</italic> L. (lemon balm) inoculated with arbuscular mycorrhizal fungi (AMF) under different rates of phosphorus (P). Treatments comprised a high and low P rate combined or not with inoculation of <italic>Rhizophagus clarus</italic> (C. Walker &amp; A. Schüßler) or <italic>Claroideoglomus etunicatum</italic> (C. Walker &amp; A. Schüßler), arranged according to a 2 × 3 factorial design with 8 replications. At 4 months after transplanting, shoot fresh and dry weights increased in both AMF-inoculated treatments under a low P rate. There was an increase in shoot P content with <italic>C. etunicatum</italic> inoculation under a high P rate. EO yields ranged from 0.04% to 0.12% and increased with <italic>R. clarus</italic> inoculation. Eighteen compounds were identified in EOs. The major components were geranial (43.96%–54.93%), neral (29.95%–34.66%), geraniol (3.11%–12.85%), and (<italic>E</italic>)-caryophyllene (2.62%–6.66%). It was concluded that AMF inoculation increased plant growth, improved EO yield, and modified EO composition. It is recommended to inoculate lemon balm with <italic>R</italic>. <italic>clarus</italic> under low P rates.</p> </abstract>