Changes in the Essential Oil Composition during Fennel Growth and Development

摘要

Using stage sampling methods, the growth and development of Inner Mongolia fennel (Foeniculum vulgare) was investigated, including its essential oil composition. The plant height, dry weight (DW), and C/N ratio displayed increasing S-shaped curves during fennel growth from seedling to fruit ripening. The essential oil content displayed a nearly linear increase, while the soluble sugar content initially declined, then stabilized and finally increased. The total carbon content was relatively constant, with a slight uptrend. The total and protein nitrogen contents decreasing sharply, then maintained a relatively low level. The essential oil content, plant height, plant DW, total carbon content, and C/N ratio were positively correlated with each other in the different developmental stages. The total nitrogen also showed a significant positive correlation. In contrast, the essential oil content, plant height, DW, total carbon content, and C/N ratio were negatively correlated with the total nitrogen contents. Twenty-five fennel essential oil components were identified, and the predominant varieties did not significantly differ among the developmental stages. Finally, the relative content of (E)-anethole declined initially and increased thereafter, while the relative content of limonene displayed inverse changes.