Submitted to: American Society for Horticultural Science
Publication Type: Abstract Only
Publication Acceptance Date: April 29, 1999
Publication Date: N/A
Technical Abstract: The influence of a wide range of CO2 levels on the growth, morphogenesis, and secondary metabolite production in vitro was evaluated. Shoots of thyme (Thymus vulgaris L.) and a spearmint-peppermint cross (Mentha spicata x Mentha piperita) were grown on MS medium with and without 3% sucrose under 350, 1,500, 3,000, 10,000, and 30,000 uL CO2 liter**-1 for eight weeks. Dichloromethane extracts from leafs were analyzed using GC-MS techniques. Prominent peaks were identified by comparison with known standards. Highest growth (i.e., fresh weight) and morphogenesis responses (i.e., leafs, shoots, and roots) were obtained when shoots were grown under 10,000 uL CO2 liter**-1 regardless of whether or not sucrose was included in the medium. Ultra-high CO2 concentrations (>3,000 uL CO2 liter**-1) stimulated secondary metabolite production regardless of whether or not the medium contained sucrose. However, the combination of certain ultra-high CO2 levels (e.g., 3,000 to 10,000 uL CO2 liter**-1) and the presence of sucrose in the medium resulted in shoots producing the highest levels of secondary metabolites. These results suggest that in vitro photosynthesis, which is stimulated by ultra-high carbon dioxide levels, may enhance secondary metabolite production.