Abstract
Plants commonly respond to environmental stress with a production and /or release of specific flavor components. Some of the secondary induced chemicals are known to work as allelochemics. On the other hand, recent reports say atmospheric concentration of carbon dioxide (CO2) tends to increase on a global basis. This study aims to investigate the potential effect of CO2 level on the metabolite and release of flavor components of plants. Flavor components from/in the leaves of five kinds of herbs were determined by Head Space and MTBE extraction methods coupled with Gas Chromatography/Mass Spectrometer under both ambient CO2 concentration and elevated level (ca. 700ppm, double the present atmosphere) in a growth chamber. Significant differences were found for herbaceous plants such as Ocimum basilicum, Origanum vulgare and Mellissa officinalis, in emissions, extracted amounts and chemical compositions of terpenoids and phenypropanoids, when exposed to the elevated CO2 concentration. Meanwhile, no apparent changes were found for woody plants such as Salvia elegans and Eucalyptus citriodor. This means a change in CO2 concentration is a possible environmental stress at least on the herbaceous plants, whose photosynthetic rates are commonly greater than those of woody plants.
