Effects on growth, essential oil content and composition of the volatile fraction of Achillea millefolium L. cultivated in hydroponic systems deficient in macro- and microelements

Abstract

The aim of the study was to determine which elements effect the growth, essential oil content and composition of the volatile fraction of Achillea millefolium L. Acclimated scions were transferred into pots containing either complete nutrient solution or a solution of equivalent compositionbut lacking one of the elements N, P, K, Ca, Mg, S, Fe, B, Zn, B, Mo or Cu. The experiment was of completely randomized design, and each of the thirteen treatments was replicated four times with each replicate comprising two plants. Plants were cultured in the greenhouse under natural light for 55 days, under hydroponic conditions. Visual symptoms of element deficiency were assessed daily. Plants were harvested at the end of the culture period and growth parameters (number of leaves; stem diameter; root size; shoot, root and total dry matter), (levels of chlorophylls a; b; total chlorophyll and carotenoids), content of essential oil, and compositions of leaf headspace volatile fractions were evaluated. The results showed that the composition of the nutrient solution exerted a significant effect on all of the growth parameters, although visual symptoms of nutrient deficiency were more marked following omission of macroelements compared with microelements. With regard to total dry matter, the order of limiting nutrients was Ca = K = N > P > S > Mg for macroelements and Zn > Fe > B > Cu > Mn > Mo for microelements. Omission of P, S, B or Mn induced increases in essential oil content. The major components of the volatile fractions were identified as sabinene, 1,8-cineol, borneol, β-caryophyllene and β-cubebene, and the proportions of these compounds were affected substantially by the omission of macro-or microelements.