Arbuscular mycorrhizal fungi and phosphorus in spilanthol and phenolic compound yield in jambu plants

Fungos micorrízicos arbusculares e fósforo na produção de espilanthol e composto fenólico em plantas de jambu

ABSTRACT

Jambu has spilanthol and phenolic compounds that are responsible for several medicinal properties. Besides improving nutrient absorption, arbuscular mycorrhizal fungi (AMF) can change secondary metabolites’ yield. Thus, the aim of the current study was to evaluate AMF inoculation and P influence on shoot dry biomass yield, macronutrient content (N, P, K, Ca and Mg), total phenol contents and spilanthol percentage in jambu plants. The experiment followed a randomized block design at 3x4 factorial arrangement, with two AMF (Rhizophagus clarus and Claroideoglomus etunicatum) and without AMF, at four P doses (0, 30, 60 and 90 mg/kg of soil), with four replicates. Plants inoculated with R. clarus and C. etunicatum, grown without phosphate fertilization, presented increase by 23 and 12 times, respectively, in comparison to plants without AMF. The relative spilanthol area in plants inoculated with R. clarus, without phosphate fertilization, reached 2.4%. Shoot dry biomass yield of jambu plants and the P, K, Ca and Mg contents were higher when plants were inoculated with R. clarus at the lowest P doses. The AMF also increased the contents of total phenols in plants fertilized with 60 mg kg^-1. This P dose increased spilanthol concentration in jambu plants inoculated with C. etunicatum.

Keywords:
Acmella oleacea; Rhizophagus clarus; Claroideoglomus etunicatum; mycorrhizae; secondary metabolism; nutrients