‘Scotch’ spearmint ( Mentha × gracilis Sole. = M. cardiaca L.) and ‘Native’ spearmint ( Mentha spicata L.) are well-known and widely grown essential oil crops in many countries, including the United States ( Bienvenu et al., 1999 ; Lawrence
Valtcho D. Zheljazkov, Charles L. Cantrell, Tess Astatkie and Ekaterina Jeliazkova
Brent Tisseret* and Steven Vaughn
The influence of altering the physical environment on the growth (fresh weight), morphogenesis (leaf, root, and shoot numbers) and secondary metabolism (i.e., volatile monoterpene, and carvone) of Mentha spicata L. (spearmint) shoots cultured on MS medium was studied. The type of physical support (e.g., agar, liquid, platforms, or glass supports) using Magenta vessels altered growth and morphogenesis. Mint shoots grown on liquid produced 4-x fold more fresh weight than on agar. Carvone levels were unaffected physical supports. Increasing the frequency of media replacement significantly increased growth without altering carvone. Vessel size influence was tested by culturing shoots on culture tubes, Magenta vessels and ½-gal. jars. Positive correlations occurred between vessel capacity and culture growth, morphogenesis and carvone levels. A comparative study testing several spearmint cultivars on either culture tubes or an automated plant culture system (APCS, a sterile hydroponics system) was conducted. The APCS produced more biomass (e.g., ≈15-x fold increase in fresh weight), morphogenesis and carvone than employing culture tubes. Carvone was only produced from shoots and was absent in either roots or callus. Carvone levels decreased proportionally in shoots as the distance from the shoot terminus increased. Altering the number of media culture immersions (4, 8, 12, or 16 immersions/day) with the APCS was tested. Twelve immersions of media/day was optimum. Higher culture growth rates resulted in lower carvone levels/culture; however, overall carvone levels/vessel increased due to greater biomass production.
Valtcho D. Zheljazkov, Tess Astatkie, Thomas Horgan and S. Marie Rogers
turkey meat to inhibit lipid oxidation and the development of rancid off-flavors ( Mielnik et al., 2008 ). We hypothesized that residual distillation water could have an effect on peppermint ( Mentha × piperita L.) and spearmint ( Mentha spicata L
Valtcho D. Zheljazkov, Tess Astatkie and Ekaterina Jeliazkova
‘Native’ spearmint, Mentha spicata L., is one of the two widely grown spearmints in the United States and throughout the world ( Bienvenu et al., 1999 ; Lawrence, 2006 ; Topalov, 1989 ). The other spearmint is ‘Scotch’ spearmint, which actually
Steven F. Vaughn, Mark A. Berhow and Brent Tisserat
( Tagetes patula L.), and spearmint ( Mentha spicata L.) seeds were obtained from the U.S. Department of Agriculture, ARS, National Germplasm Repository, Corvallis, OR, and were planted in Cone-tainers (Hummert International, Earth City, MO; 25-mm diameter
Valtcho D. Zheljazkov, Tess Astatkie and Ekaterina Jeliazkova
The United States is a major producer of EO from peppermint ( Mentha × piperita L.) and spearmints such as ‘Native’ spearmint ( Mentha spicata L.) and ‘Scotch’ spearmint ( Mentha × gracilis Sole.; syn. M. cardiaca L.) [ Lawrence, 2006 ; Mint
Brent Tisserat and Amy Stuff
of a greenhouse. Materials and Methods Plant materials. Carrot seeds ( Daucus carota L. ‘Chantenay’), Dwarf Corn ( Zea mays L. cv. Gaspé Flint) seeds, and spearmint ( Mentha spicata L. PI # ‘294099’) plantlets as sterile shoot cuttings were used
J.M. Van Eck and S.L. Kitto
Plant regeneration from callus cultures of mint depended on expiant source, genotype, and culture medium components. Mature embryos, seedling and flower parts, as well as chilled or desiccated immature embryos of peppermint (Mentha piperita L.) and spearmint (Mentha spicata L.) were cultured on a Murashige-Skoog medium containing various combinations of growth factors. Shoots regenerated from callus that developed either on mature peppermint embryos cultured on medium that contained BA at 0.5 mg·liter-1 and NAA at 0.5 mg·liter-1 or on immature peppermint embryos (chilled at SC for 0.6 day or nonchilled) cultured on basal medium containing BA at 1 mg·liter-1 and TIBA at 1 mg·liter-1 Shoots were proliferated, rooted, and acclimated. with 100% survival under greenhouse conditions. Chemical names used: N-(phenylmethyl) -1H-purin-6-amine (BA); 1-naphthaleneacetic acid (NAA); 2,3,5-triiodobenzoic acid (TIBA).
A.L. Fenwick and S.M. Ward
Seventeen mint accessions representing the three species grown for commercial oil production in the United States were characterized using randomly amplified polymorphic DNA (RAPD) analysis. The RAPD profiles readily identified the different Mentha species; calculation of genetic distance, based on the number of shared bands, indicated that M. spicata L. is more closely related to M. × gracilis than to M. × piperita. The RAPD profiles also distinguished among eight peppermint accessions of different geographical origin. However, only limited polymorphism was observed among the most widely grown peppermint and Scotch spearmint cultivars. These results indicate a potential lack of genetic diversity in mint cultivars grown for oil in the United States.
Brent Tisserat and Steven Vaughn
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 × Mentha piperita) were grown on MS medium with and without 3% sucrose under 350, 1500, 3000, 10,000, and 30,000 μL CO2/L for 8 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 μL CO2/L regardless of whether or not sucrose was included in the medium. Ultra-high CO2 concentrations (3000 μL CO2/L) stimulated secondary metabolite production regardless of whether or not the medium contained sucrose. However, the combination of certain ultra-high CO2 levels (e.g., 3000 to 10,000 μL CO2/L) 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 ultrahigh CO2 levels, may enhance secondary metabolite production.