Effect of phosphorus uptake on growth and secondary metabolites of garden sage (Salvia officinalis L.)

BACKGROUND: Garden sage (Salvia officinalis L., Lamiaceae) has gained importance during the last decade as a natural antioxidant, mainly owing to the antioxidant secondary plant metabolites rosmarinic acid (RA) and diterpenes such as carnosic acid. The aim of this work was to study the biomass production, the concentrations of total phenolics and RA and the essential oil of garden sage in response to phosphorus (P) supply. The treatments included P fertilisation and inoculation with arbuscular mycorrhizal fungi (AMF), since AMF are the most efficient biotic factor promoting the P uptake of plants. RESULTS: The P concentration in the plant was highest in P-fertilised plants, intermediate in AMF-inoculated plants and lowest in non-inoculated/non-P-supplied plants. The leaf biomass increased only in P-fertilised plants. AMF-inoculated plants, in contrast, did not show an increased leaf biomass, but their root biomass was enhanced. The total phenolic and RA concentrations were affected differently in leaves and roots, with the highest concentration and yield being found in leaves of P-fertilised plants. In none of the treatments were the essential oil concentration and composition affected. CONCLUSION: Optimal P fertilisation improves the antioxidant potential of garden sage and increases its biomass yield, thus optimising agronomic production of this plant for antioxidant use. (C) 2009 Society of Chemical Industry