‘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 is a different species (Mentha ×gracilis Sole.; syn. M. cardiaca L.). ‘Native’ spearmint is a major essential oil crop grown in the Midwest and in the northwestern United States (National Agricultural Statistic Service, 2009). However, ‘Native’ spearmint has a wide environmental adaptation, and recent studies demonstrated feasibility of growing it under the humid conditions of Mississippi (Zheljazkov et al., 2010a, 2010b, 2012a). Indeed, the natural distribution of Mentha spicata L. spans from Alaska and British Columbia to Texas and Florida in North America [U.S. Department of Agriculture (USDA), 2012].
Recent studies in Wyoming indicated that ‘Native’ spearmint can withstand the first fall frost and apparently could be developed as a crop for northern Wyoming at 1170 m a.s.l. elevation (Zheljazkov et al., 2012a). Developing means for increased biomass and oil yields and increased concentrations of carvone, the main essential oil constituent of ‘Native’ spearmint, would be beneficial for the existing and future spearmint essential oil industry. There have been various studies aiming to improve essential oil yield and composition of spearmints. For example, previous studies demonstrated that some plant hormones such as MJ may increase carvone concentration of ‘Scotch’ spearmint (Zheljazkov and Astatkie, 2011a). In another study, the application of MJ had no significant effect on essential oil content of ‘Native’ spearmint (Zheljazkov et al., 2010b). In the same study, the application of distillation water from wild bergamot (bee balm) (Monarda fistulosa L.) increased the essential oil content, whereas the distillation water of absinthe wormwood (Artemisia absinthium L.), lavender (Lavandula vera DC), and wild bergamot increased oil yields of ‘Native’ spearmint (Zheljazkov et al., 2010b). In other studies, it was shown that plant hormones or plant extracts may have a significant effect on spearmint and peppermint essential oil yields and composition (Zheljazkov and Astatkie, 2011b, 2012). These reports suggest that MJ and some plant extracts may have potential for improving spearmint oil content and composition.
Rocky mountain juniper (Juniperus scopulorum Sarg.) and big sagebrush (Artemisia tridentata Nutt.) are two of the most widely spread native plants in the semiarid regions of western United States, Mexico, and Canada (USDA, 2011). These species provide cover for a number of wildlife species and food for many birds, whitetail deer, elk, bighorn sheep, pronghorn antelope, but also for cattle and sheep (Scher, 2002). Both species contain a significant amount of plant secondary metabolites. Rocky Mountain juniper contains podophyllotoxin and essential oil (Cantrell et al., 2013; Zheljazkov et al., 2013). Big sagebrush contains essential oil, MJ (Jassbi et al., 2010), and other plant chemicals. Junipers and sagebrush have been shown to exert allelopathic effects on surrounding species (Jassbi et al., 2010; Preston et al., 2002; Yager and Smeins, 1999). On the other hand, Tween20 has also been investigated as a means for improving essential oil content of some aromatic plants (Dobreva et al., 2011).
There are no studies in the literature whether foliar application of Rocky Mountain juniper or sagebrush extracts could modify essential oil content and composition of spearmints. The hypothesis of this study was that Rocky Mountain juniper and sagebrush essential oil and plant extracts may have significant effect on essential oil yields, content, and composition of ‘Native’ spearmint grown under Wyoming conditions.
Bienvenu, F., Peterson, L. & Edwards, J. 1999 Native and Scotch spearmint oil production in Tasmania and Victoria. A report for Rural Industries Research and Development Corporation. Publ. #99/147, Project #DAV-101A, p32. 7 Feb. 2013. <https://rirdc.infoservices.com.au/downloads/99-147>
Cantrell, C.L., Zheljazkov, V.D., Osbrink, W.A., Castro, A., Maddox, V., Craker, L.E. & Astatkie, T. 2013 Podophyllotoxin and essential oil profile of Juniperus and related species Ind. Crops Prod. 43 668 676
Chowdhury, J.U., Nandi, N.C., Uddin, M. & Rahman, M. 2007 Chemical constituents of essential oils from two types of spearmint (Mentha spicata L. and M. cardiaca L.) introduced in Bangladesh Bangl. J. Sci. Indus. Res. 42 79 82
Dobreva, A., Kovatcheva, N., Astatkie, T. & Zheljazkov, V.D. 2011 Improvement of essential oil yield of oil-bearing rose (Rosa damascena Mill.) due to surfactant and maceration Ind. Crops Prod. 34 1649 1651
Gawde, A.J., Cantrell, C.L. & Zheljazkov, V.D. 2009 Dual extraction of essential oil and podophyllotoxin from Juniperus virginiana Ind. Crops Prod. 30 276 280
Jassbi, A.R., Zamanizadehnajari, S. & Baldwin, I.T. 2010 Phytotoxic volatiles in the roots and shoots of Artemisia tridentata as detected by headspace solid-phase microextraction and gas chromatographic–mass spectrometry analysis J. Chem. Ecol. 36 1398 1407
Kizil, S. & Toncer, O. 2006 Influence of different harvesting times on the yield and oil composition of spearmint (Mentha spicata L. var. spicata) J. Food Agr. Environ. 4 135 137
Lawrence, B.M. 2006 Mint: The genus Mentha. CRC Press, Boca Raton, FL
Montgomery, D.C. 2013 Design and analysis of experiments. 8th Ed. Wiley, New York, NY
Murray, M.J., Faas, W. & Marble, P. 1972 Effects of plant maturity on oil composition of several spearmint species grown in Indiana and Michigan Crop Sci. 12 723 728
National Agricultural Statistic Service 2009 Dec. 2012. <http://www.nass.usda.gov/Statistics_by_State/Oregon/Publications/Field_Crop_Report/crop%20reports/01_13an.pdf>
Preston, C.A., Betts, H. & Baldwin, I.T. 2002 Methyl jasmonate as an allelopathic agent: Sagebrush inhibits germination of a neighboring tobacco, Nicotiana attenuata J. Chem. Ecol. 28 2343 2369
SAS Institute Inc 2010 SAS/STAT® 9.3 user’s guide. SAS Institute Inc., Cary, NC
Scher, J.S. 2002 Juniperus scopulorum. In: Fire Effects Information System [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (producer). Mar. 2013. <http://www.fs.fed.us/database/feis/plants/tree/junsco/all.html>
Sokovic, M.D., Vukojevic, J., Marin, P.D., Brkic, D.D., Vajs, V. & van Griensven, L.J.L.D. 2009 Chemical composition of essential oils of Thymus and Mentha species and their antifungal activities Molecules 14 238 249
Topalov, V.D. 1989 Mentha, p. 372-381. In: Topalov, V.D., I.I. Dechev, and M.S. Pehlivanov (eds.). Plant production. Zemizdat Press, Sofia, Bulgaria
U.S. Department of Agriculture Natural Resources Conservation Service, Plants profile: Juniperus scopulorum Sarg., Rocky Mountain juniper. 2011. Mar. 2013. <http://plants.usda.gov/java/profile?symbol=JUSC2>
U.S. Department of Agriculture Natural Resources Conservation Service. 2012. Plants database. Mentha spicata L., spearmint. Dec. 2012. <http://plants.usda.gov/java/profile?symbol=Mesp3>
Yager, L.Y. & Smeins, F.E. 1999 Ashe juniper (Juniperus ashei: Cupressaceae) canopy and litter effects on understory vegetation in a juniper–oak savanna Southwest. Nat. 44 6 16
Zheljazkov, V.D. & Astatkie, T. 2011a Effect of residual distillation water of 15 plants and three plant hormones on Scotch spearmint (Mentha × gracilis Sole) Ind. Crops Prod. 33 704 709
Zheljazkov, V.D. & Astatkie, T. 2011b Effect of distillation waste water and plant hormones on spearmint growth and composition J. Sci. Food Agr. 91 1135 1141
Zheljazkov, V.D., Cantrell, C.L., Astatkie, T. & Ebelhar, M.W. 2010a Productivity, oil content and composition of two spearmint species in Mississippi Agron. J. 102 129 133
Zheljazkov, V.D., Astatkie, T., Horgan, T. & Rogers, S.M. 2010b Effect of plant hormones and distillation water on mints HortScience 45 1338 1340
Zheljazkov, V.D., Cantrell, C.L., Astatkie, T. & Jeliazkova, E. 2012a Fall frosts effects on the essential oil of “Native” spearmint in Wyoming HortScience 47 1603 1606
Zheljazkov, V.D., Astatkie, T., Jeliazkova, E.A. & Schlegel, V. 2012b Distillation time alters essential oil yield, composition, and antioxidant activity of male Juniperus scopulorum trees J. Oleo Sci. 61 537 546
Zheljazkov, V.D. & Astatkie, T. 2012 Distillation waste water can modify peppermint (Mentha ×piperita L.) oil composition Ind. Crops Prod. 36 420 426
Zheljazkov, V.D., Cantrell, C.L., Donega, M.A. & Astatkie, T. 2013 Bioprospecting for podophyllotoxin in the Big Horn Mountains, Wyoming Ind. Crops Prod. 43 787 790