Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2003
Publication Date: 12/1/2003
Citation: Tisserat, B., Vaughn, S.F. 2004. Techniques to improve growth, morphogenesis, and secondary metabolism responses from lamiaceae species in vitro. Acta Horticulturae. 629:333-339. Interpretive Summary: In recent years, we have found that an ultra-high level of carbon dioxide (CO2) greatly improves overall growth and development of various plant species. We studied a broad range of CO2 atmospheric environments administered to tissue cultures of several mint family members. Growth, morphogenesis, and secondary metabolism were studied in order to develop propagation techniques useful to the commercial nursery industry. Catnip, oregano, spearmint, and sweet basil were the mint family employed in this study. These plants are important crops to over a dozen Midwest and Pacific Northwest States. A great commercial demand exists for large numbers of desirable disease-free clones for field transplants. Our results indicate that these species grew well in a broad range of CO2 atmospheres (up to 3%) with 1% usually being optimum. In addition, secondary metabolite (carvone) levels increased in spearmint as the CO2 levels increased and is closely associated with improved growth responses. We also employed an automated plant tissue culture system to enhance mint culture growth and shoot development. We developed CO2 treatment cultural techniques that enhance mint propagation by improving growth and secondary metabolism that can be employed by the commercial plant tissue culture industry.
Technical Abstract: Cultural procedures to improve growth (fresh weight) and morphogenesis (leaves, shoots, and roots) responses from mint family (Lamiaceae) species (e.g., basil, catnip, oregano, and spearmint) in vitro are presented. Novel plant tissue culture systems were employed to increase biomass and shooting. A survey study with several species is presented testing a wide range of CO2 levels. Employment of ultra-high levels of CO2 (i.e., >3,000 uL CO2 L**-1) promoted greater growth and morphogenesis in most mint species compared to that obtained employing ambient air (350 uL CO2 L**-1). Employment of a sterile hydroponics system, i.e., an automated plant culture system (APCS), greatly enhanced spearmint biomass and shooting over that obtained employing an agar medium. Analysis of essential oil composition in spearmint cultures grown in various culture systems reveals that high secondary metabolite production is often associated with high growth and morphogenesis responses.