Submitted to: Phytochemical Society of North America Meeting and Newsletter
Publication Type: Abstract Only
Publication Acceptance Date: 8/8/2003
Publication Date: 8/13/2003
Citation: Tisserat, B., Berhow, M.A. 2003. Carbon levels influence rosmarinic acid levels in tissue cultures of Mentha spicata l [abstract]. Phytochemical Society of North America. p. 39.
Technical Abstract: Rosmarinic acid is constitutively expressed in spearmint (Mentha spicata L.) grown in vitro. However, high positive correlations occur between carbon levels and spearmint plantlet growth (fresh weight), morphogenesis (leaves, roots, and shoots), and rosmarinic acid concentrations (mg rosmarinic acid/g dry weight). Spearmint shoots were grown under 350, 1,500, 3,000, 10,000 or 30,000 umol mol**-1 CO2 for 8 wks on a Murashige and Skoog medium containing 3% sucrose under a 16-h (day)/8-h (light) photoperiod at a light intensity of 180 umol s**-1 m**-2. Increased levels of CO2 produced increased growth, morphogenesis, and rosmarinic acid concentrations. For example, plantlets grown in 350 umol mol**-1 CO2 produced 5.2 ± 1.19 mg rosmarinic acid/g dry weight while plantlets grown under 30,000 umol mol**-1 CO2 produced 25.7 ± 2.03 mg rosmarinic acid/g dry weight. In other experiments, the influence of media carbon on spearmint shoots growth, morphogenesis, and secondary metabolism was tested. Spearmint shoots were grown under 0.0, 0.3, 1.0, 3.0, and 5.0% sucrose, glucose, or fructose under ambient CO2. Regardless of the carbohydrate type, increasing the carbohydrate levels resulted in a corresponding increase in rosmarinic acid concentrations. However, growth and morphogenesis increased proportionally with the carbohydrate levels to reach a maximum at 3%, and these responses declined thereafter. These results suggest that high plant growth and morphogenesis and secondary metabolism can all occur simultaneously in vitro. Carbon levels supplied by either the nutrient medium or by the atmosphere significantly influenced rosmarinic acid concentrations.