Effects of Zn concentration on Zn accumulation and essential oil components in fennel (Foeniculum vulgare Mill.) plant

By solution culture method, effects of Zn concentrations (0.5 mg/L, 10 mg/L, 20 mg/L, 30 mg/L, 40 mg/L and 50 mg/L) on fennel plant (Foeniculum vulgare L.) growth, secondary metabolites essential oil components, and absorption and accumulation characteristics of fennel plant to Zn were studied. The results showed that, height and fresh weight (FW) aboveground of fennel plant increased significantly by 5 mg/L Zn, while plant height, FW underground and dry weight(DW) aboveground and underground decreased in groups treated with high concentrations of Zn. Furthermore, Zn was mainly accumulated in the roots of plants. With the increase of Zn concentration, the content of Zn aboveground and total Zn in fennel plant first increased and then decreased, and reached the maximum values at the concentration of 30 mg/L, and the content of Zn underground first increased sharply and then showed a slow increasing trend, and transfer coefficient (TF) decreased accordingly. In addition, 24 kinds of components in essential oil of fennel plant were identified, and its main content was (E)-Anethole which reached the highest in the treatment with 10 mg/L Zn, and it showed no significance between the other Zn treatments and the control. Therefore, fennel plant can be used for phytoremediation of Zn contaminated soil. When Zn reaches a certain concentration, Zn content in fennel plant begins to decline. However, the quality of essential oil is not affected significantly.