Submitted to: Journal of Herbs, Spices and Medicinal Plants
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/14/2001
Publication Date: 1/14/2001
Citation: TISSERAT, B. INFLUENCE OF ULTRA-HIGH CARBON DIOXIDE LEVELS ON GROWTH AND MORPHOGENESIS OF LAMIACEAE SPECIES IN SOIL. JOURNAL OF HERBS SPICES AND MEDICINAL PLANTS. 2002. V. 9. P. 81-89. Interpretive Summary: A major bi-product in alcohol fermentation is carbon dioxide (CO2); much of this is vented into the atmosphere as waste. This work was conducted in an effort to determine if this excess CO2 can be developed into a high-value-added product. The influence of various concentrations of CO2 including ultra-high CO2 levels (> 3,000 uL CO2 liter**-1) to obtain optimum growth of Labitae plants was studied in order to find the best situation for the employment of CO2. For example, growth rates can be accelerated 2.6x and more by growing thyme plants under 3,000 uL CO2 liter**-1 compared to plants grown under 350 uL CO2 liter**-1 (ambient air CO2 level). This information will benefit the commercial tissue culture/nursery industry in accelerating the growth of plants and finding a byproduct use for the excess CO2 generated during the fermentation process.
Technical Abstract: The growth (fresh weight) and morphogenesis (leaves, roots, and shoots) of spearmint (Mentha spicata L.), thyme (Thymus vulgaris L.), and watermint (Metha aquatica L.) plants were determined after 4 weeks under 350, 1,500, 3,000, 10,000, and 30,000 uL CO2 liter**-1. Plants were grown in a vermiculite-peat moss mixture within a greenhouse employing natural sunlight. For all three species tested, ultra-high CO2 levels (i.e., >3,000 uL CO2 liter**-1) substantially increased fresh weight, leaf, root, and shoot numbers with all plants compared to plants grown on the same soil conditions under ambient air (350 uL CO2 liter**-1) and high CO2 levels (1,500 uL CO2 liter**-1). Invariably, the 3,000 and 10,000 uL CO2 liter**-1 levels provided for the largest growth and morphogenesis yields for all CO2 levels tested. For example, fresh weight of spearmint and watermint increased 2.5 and 3.2 x-fold, respectively, when grown under 10,000 uL CO2 liter**-1 compared to growth obtained under 350 uL CO2 liter**-1. Thyme fresh weight increased 2.6 x-fold under 3,000 uL CO2 liter**-1 compared to growth obtained under ambient air. Pretreatment of tissue culture shoots with an elevated CO2 level (10,000 uL CO2 liter**-1) was compared with pretreatment of shoots with ambient air (350 uL CO2 liter**-1) for 8 weeks prior to transferring to soil conditions in order to determine if any improvement in their subsequent growth and morphogenesis could be obtained. Shoots given a prior elevated CO2 pretreatment invariably exhibited higher growth and morphogenesis rates when transferred to soil conditions compared to shoots pretreated with ambient air regardless of whether shoots were subsequently grown on ambient air (350 uL CO2 liter**-1) or elevated CO2 levels (10,000 uL CO2 liter**-1).