@article {1981,
	title = {Essential oils enhanced by ultra-high carbon dioxide levels from Lamiaceae species grown in vitro and in vivo},
	journal = {Plant Cell Reports},
	volume = {20},
	year = {2001},
	month = {2001///},
	pages = {361 - 368},
	address = {Affiliation: U.S. Department of Agriculture, Agricultural Research Service, Natl. Ctr. Agric. Utiliz. Res., 1815 N. University St., Peoria, IL 61604, United States},
	abstract = {The growth (fresh weight), morphogenesis (leaves, roots and shoots) and essential oil composition of mint (Mentha sp. L.) and thyme (Thymus vulgaris L.) plants were determined after 8 weeks under 350, 1,500, 3,000, 10,000 and 30,000 μmol mol-1 CO2. Plants were grown in vitro on basal medium (BM) consisting of Murashige and Skoog salts and 0.8\% agar that contained either 0 or 3\% sucrose under a 16-h (day)/8-h (night) photoperiod at a light intensity of 180 μmol s-1 m-2 or in soil in a greenhouse under conditions of natural sunlight. Ultra-high CO2 levels (i.e. >=3,000 μmol mol-1 CO2) substantially increased fresh weights, leaves, shoots and roots for all plants compared to plants grown under ambient air (350 μmol mol-1 CO2) both in vivo and in vitro. For both species, 10,000 μmol mol-1 CO2 was the optimum concentration to obtain the largest growth and morphogenesis responses under in vitro conditions, while the 3,000- to 10,000-μmol mol-1 CO2 range provided the largest yields for soil-grown plants. Essential oil composition (i.e. monoterpenes, piperitonone oxide and limonene from mint and aromatic phenol and thymol from thyme) from the shoot portion of plants grown at all CO2 levels was analyzed in CH2Cl2 extracts via gas chromatography. Higher levels of secondary compounds occurred in vitro when cultures were grown under ultra-high CO2 levels than in ambient air. The concentration of thymol, a major secondary compound in thyme plants grown on BM containing sucrose, was 317-fold higher at 10,000 μmol mol-1 CO2 than in plants grown under ambient air conditions with the same BM. The levels of secondary compound in in-vitro-grown plantlets exposed to ultra-high CO2 concentrations exceeded those occurring in plants grown in the greenhouse under the same CO2 levels. Substantially higher levels of secondary compound occurred in plants under ultra-high CO2 levels on BM containing sucrose than on BM lacking sucrose or in soil. Thymol levels in thyme plants grown on BM containing sucrose were 3.9-fold higher at 10,000 μmol mol-1 CO2 than in shoots grown on BM without sucrose under the same CO2 levels. High positive correlations occurred between thymol concentrations and CO2 levels, fresh weights, shoots, roots and leaves when thyme shoots were grown on BM with sucrose. High positive correlations for thyme shoots grown on BM without sucrose only occurred between thymol concentrations and CO2 levels, fresh weights, shoots and leaves. No positive correlations between thymol concentrations and CO2 levels or any growth or morphogenesis responses occurred for thyme shoots when grown in soil.},
	keywords = {CO2 enrichment, limonene, Piperitenone oxide, Rooting, Shooting},
	url = {http://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-0034931446\&partnerID=40\&rel=R6.5.0},
	author = {Tisserat, B and Vaughn, S F}
}
@article {1982,
	title = {Influence of modified oxygen and carbon dioxide atmospheres on mint and thyme plant growth, morphogenesis and secondary metabolism in vitro},
	journal = {Plant Cell Reports},
	volume = {20},
	year = {2002},
	note = {From Duplicate 1 (                           Influence of modified oxygen and carbon dioxide atmospheres on mint and thyme plant growth, morphogenesis and secondary metabolism in vitro                         - Tisserat, B; Vaughn, S F; Silman, R )                
},
	month = {2002/03//},
	pages = {912 - 916},
	address = {Affiliation: U.S. Department of Agriculture, National Center for Agricultural Utilization Research, Fermentation Biotechnology Research Unit, 1815 N University St., Peoria, IL 61604, United States; Affiliation: U.S. Department of Agriculture, National Cen},
	abstract = {Growth (fresh weight) and morphogenesis (production of leaves, roots and shoots) of mint (Mentha sp. L.) and thyme (Thymus vulgaris L.) shoots were determined under atmospheres of 5\%, 10\%, 21\%, 32\%, or 43\% O2 with either 350 or 10,000 μmol mol-1 CO2. Plants were grown in vitro on Murashige and Skoog salts, 3\% sucrose and 0.8\% agar under a 16/8-h (day/night) photoperiod with a light intensity of 180 μmol s-1 m-2. Growth and morphogenesis responses varied considerably for the two plant species tested depending on the level of O2 administered. Growth was considerably enhanced for both species under all O2 levels tested when 10,000 μmol mol-1 CO2 was added as compared to growth responses obtained at the same O2 levels tested with 350 μmol mol-1 CO2. Mint shoots exhibited high growth and morphogenesis responses for all O2 levels tested with 10,000 μmol mol-1 CO2. In contrast, thyme shoots exhibited enhanced growth and morphogenesis when cultured in >=21\% O2 with 10,000 μmol mol-1 CO2 included compared to shoots cultured under lower O2 levels. Essential oil compositions (i.e. monoterpene, piperitenone oxide from mint and aromatic phenol, thymol from thyme) were analyzed from CH2Cl2 extracts via gas chromatography from the shoot portion of plants grown at all O2 levels. The highest levels of thymol were produced from thyme shoots cultured under 10\% and 21\% O2 with 10,000 μmol mol-1 CO2 and levels were considerably lower in shoots grown under either lower or higher O2 levels. Higher levels of piperitenone oxide were obtained from mint cultures grown under >=21\% O2 with 10,000 μmol mol-1 CO2 compared to that obtained with lower O2 levels.},
	keywords = {CO2 enrichment, Lamiaceae, Mentha sp., Thymol, Thymus sativa},
	url = {http://www.scopus.com/scopus/inward/record.url?eid=2-s2.0-0036218904\&partnerID=40\&rel=R6.5.0},
	author = {Tisserat, B and Vaughn, S F and Silman, R}
}
