Growth promotion and elicitor activity of salicylic acid in Achillea millefolium L.
Salicylic acid (SA) is a phenolic compound present in plants and has multiple functions, including hormonal effect on stimulus of plant growth and development and induction of plant defense responses under conditions of biotic and abiotic stresses. Studies related to SA’s elicitor action on the synthesis of secondary metabolite in medicinal plants have been conducted in order to increase the economic value of these species. The objective of this study was to determine the effect of SA foliar application on biomass production and the synthesis of secondary compounds in yarrow (Achillea millefolium L. - Asteraceae). The experiment was conducted in potted plants under greenhouse conditions. The SA application was done at concentrations of 0, 0.25, 0.50 and 1.00 mM 20 days after transplanting the seedlings to pots. The effect of SA on the metabolism of yarrow plants was evaluated through biometric parameters of growth and biochemical parameters. The SA at 0.50 mM resulted in linear increases in biomass accumulation of roots, total dry mass, ratio root/shoot and chlorophyll a and chlorophyll a+b content in yarrow plants.The application of SA at 0.50 and 1.00 mM was most effective in eliciting the production of essential oils and total phenols, with a consequent improvement of the antioxidant activity of the plant extract. It can be concluded that SA application constitutes an advantageous management practice for commercial production of Achillea millefolium, increasing the nutraceutical and medicinal values of this species.
Key words: Photosynthetic pigments, essential oil, phenolic compounds, antioxidant activity.