Effects of foliar zinc applications on some yield parameters and essential oil constituents of the mastic tree (Pistacia lentiscus var. chia Duham.)

Abstract

Mastic tree (Pistacia lentiscus var. chia Duham.) is an important medicinal aromatic plant which is being cultivated without any regular fertilization generally. Foliar Zn applications have great importance for many commercial plant species because of their important role in metabolic activities. In this study, the effects of foliar ZnSO4 sprayings (0, 0.2, 0.4, 0.8%) applied at 50% and 100% leafing stages, on some yield parameters and essential oil composition of mastic tree were assessed. A field experiment was carried out for two consecutive years at Ege University, Turkey. Mastic resin yield was more than doubled with 0.8% Zn particularly in the second year. The highest leaf Zn content was measured as 187.8 mg l−1 with 0.8% zinc spraying while it was 35.4 mg l−1 in unsprayed trees at 100% leafing in the first year. Leaf essential oil and α-tocopherol contents were not significantly influenced by different Zn levels and leafing stages in both years. As for the major essential oil constituents, β-myrcene (62.4%), germacrene-D (14.3%), α-terpinenyl acetate (5.52%), t-caryophyllene (2.1%) and α-pinene (1.4%) were determined. Zinc sprayings increased the β-myrcene, germacrene-D and α-pinene contents particularly at 100% leafing in the first year. In mastic tree two consecutive applications of Zn seems to be necessary for reaching to desirable leaf Zn contents. Application of 0.8% Zn or more would be proper to increase the contents of most parameters assessed.