STUDY OF THE EFFECT OF ABIOTIC AND BIOTIC STRESS ON THE GROWTH DEVELOPMENT AND SECONDARY METABOLISM OF MEDICINAL PLANT SPECIES

Achillea collina Becker ex Rchb., a medicinal plant rich in volatile compounds, was used to study the effects of biotic and abiotic stresses over plant growth and secondary metabolism. Biotic stress was induced by Myzus persiceae Sulzer and Macrosiphoniella millefolii (De Geer ), a generalist and specialist aphid species respectively. Abiotic stress was caused by mechanical damages provoked by a pin and a specially built equipment which apply a controlled and extended pressure to the plants. Plant growth and volatile compounds emissions were evaluated in the different experimental conditions analyzed. The effect of jasmonic acid on the plant volatile fingerprint was also evaluated. The volatile emission patterns obtained in the different conditions were compared in order to have suggestions regarding the metabolic pathways activated in each situation. Furthermore pea (Pisum sativum L.) and peach (Prunus persica L. Batsch) volatile fingerprints due to M. persicae infestation were analyzed and compared to those obtained from A. collina. The comparison of the results lead to the identification of volatile compounds induced only by the aphids in all the plant species studied, suggesting the activation of a common metabolic pathway due to infestation. Preliminary molecular approach seems to confirm pytochemical data.