EFFECTS OF CO2 CONCENTRATION ON PLANT GROWTH, CONTENTS AND COMPONENTS OF ESSENTIAL OIL IN FENNEL (FOENICULUM VULGARE)
REN An-Xiang, HE Jin-Ming, XIAO Yan-Hui, WANG Yu-Mei
Chin J Plan Ecolo. 2008, 32 (3):
Related Articles |
Aims The primary metabolism and secondary metabolism of plants are influenced by elevated CO2 concentration. There are many
studies on primary metabolism, but few on secondary metabolism; therefore, we studied the effect of CO2 concentration on
plant growth (primary metabolism), contents and components of essential oil (secondary metabolism) in fennel (Foeniculum
Methods After adding CO2 at three concentration levels (287.11, 532.88 and 780.46μmol·mol-1) to a sealed phytotron for 70
days, we investigated plant growth, contents and components of essential oil in fennel.
Important findings Plant height, inflorescence number, fresh and dry weight of inflorescence, whole plant dry weight and
dry mass ratio increased, while node number and whole plant fresh weight did not change significantly. Soluble sugar and
total carbon increased continuously, while total nitrogen and protein nitrogen exhibited the opposite trend. Pigment content
in leaves decreased, but chlorophyll a/b ratio was not significantly different among plants. Contents of essential oil and
yields of essential oil per plant were improved under elevated CO2 concentrations. We identified 22 kinds of components in
essential oil, but there w ere no differences in components of essential oil among different CO2 concentration treatments.
However, α-pinene, β-pinene, myrcene, p-cymene, tran-fenchylacetate and (Z)-anethole were significantly different in
relative contents of components (p<0.01), and sabinene, phellandrene, ocimene,Υ-terpinene, 2,4,6-octatriene, 3,4-dimethyl,
estragole, fenchyl acetate, copaene, fanesene and germacrene were significantly different (p<0.05).Contents of (E)-anethole
in essential oil increased under elevated CO2 concentrations, while contents of limonene de creased, but differences between
contents of (E)-anethole and those of limonene were not significant.