Variation in light quality is known to modify plant morphology, growth, and chemical constituency in plants. In the present study, the effect of light quality on growth and essential oil composition in rosemary (Rosmarinus officinalis L.) was investigated by comparing plants receiving supplemental red (660 nm) and far-red (730 nm) with each other and with control plants not receiving supplemental light. Except for the supplemental light treatments, all plants were grown under natural light conditions in a greenhouse and received full daylight, averaging 9.23 h/day during the study. The red and far-red light treatments, given as day extensions, started daily 15 min before sunset and continued for 4 h each evening for 4 weeks. No significant differences were observed in biomass yield from the different light treatments, but far-red light caused elongation of internodes and a reduction in the number of leaves in comparison with control and red-light treated plants. Essential oil production was highest in plants grown under far-red light treatments.
Giuliana Mulas and Lyle E. Craker
Valtcho D. Zheljazkov, Tess Astatkie, Barry O'Brocki, and Ekaterina Jeliazkova
Anise (Pimpinella anisum L.) is a spice, an essential oil crop, and a medicinal plant with a long history of use. Anise seed oil is extracted from anise seed through steam distillation. There is no experimentally established optimal time for distillation of anise seed. We hypothesized that the distillation time (DT) can be customized for optimum yield and composition of anise essential oil. In this study, we determined the effect of nine steam DTs (5, 15, 30, 60, 120, 180, 240, 360, and 480 minutes) on essential oil yield and essential oil composition of anise seed. We developed regression models to predict essential oil yield, the concentration of individual constituents, and the yield of these constituents as a function of DT. Highest essential oil yield (2.0 g/100 g seed, 2%) was obtained at 360-minute DT. The concentration of transanethole, the major anise oil constituent, varied from 93.5% to 96.2% (as a percent of the total oil) and generally was high at 15- to 60-minute DT and low at 240- to 480-minute DT. However, the yield of transanethole (calculated from the essential oil yield and the concentration of transanethole in the oil) increased with increasing DT to reach maximum at 360-minute DT. The concentration of the other oil constituents varied significantly depending on the DT, and some of them were higher at the shorter DT than at the longer DT. However, the yields of these constituents were highest at longer DT (either 360 or 480 minutes). DT can be used to obtain anise essential oil with different composition that would benefit the essential oil industry. This study demonstrated the need for providing DT in reports where anise seed essential oil yield and composition are discussed. This article can also be used as a reference point for comparing studies in which different DTs were used to extract essential oil from anise seed.
Shahrokh Khanizadeh and Andre Belanger
Considerable variability in susceptibility to two-spotted spider mite (TSSM) were observed for the strawberry cultivars used as parents and some of our promising selections. Large variation was observed for 9-octadecenal oil composition followed by linalool, C9H1002, decanal, β-cyclocitral, α-terpineol and (Z)-3-hexenol. The purpose of this research was to identify the relative susceptibility of selected strawberry lines to TSSM in relation to leaf essential oil composition. One objective of our breeding program is the early identification of susceptible lines and/or seedlings so that they can be eliminated prior to field trials.
Valtcho D. Zheljazkov, Charles L. Cantrell, William B. Evans, M. Wayne Ebelhar, and Christine Coker
literature ( Bowes and Zheljazkov, 2004 ; Marotti et al., 1996 ; Topalov, 1962 ; Zheljazkov, 1998 ). Essential oil composition. Overall, the oil composition was representative for sweet and holy basil ( Table 3 ; Fig. 2 ) ( Bowes and Zheljazkov
Valtcho D. Zheljazkov, Tess Astatkie, and Vicki Schlegel
, composition, and bioactivity. We hypothesized that DT may affect essential oil composition, antioxidant activity, and, hence, may be used as a tool for obtaining pine oil with desirable characteristics to meet specific market requirements. The objective of
Natasha Kovatcheva, Valtcho D. Zheljazkov, and Tess Astatkie
essential oil composition must meet the Bulgarian State Standard that was recently recognized as the international one (ISO 9842). We found differences in the number of the major essential oil constituents of the tested species and cultivars ( Table 3
Andrea L. Medina-Holguín, Sandra Micheletto, F. Omar Holguín, Jaime Rodriguez, Mary A. O'Connell, and Charles Martin
phenylpropanoids, methyeugenol, and elemicin ( Fig. 1 ). The objective of this study was to observe the effect of environmental conditions and management conditions on essential oil composition in different populations of A. californica . Fig. 1. Chemical
Bahlebi K. Eiasu, Ntombekhaya Matafeni, Viwe Dyafta, and Kenias Chigwaya
(using 10-L reacting flask mounted on heating mantle, and Inland Revenue condenser and Clevenger separator). Distillation duration (starting from the boiling of the water) was 90 min. Essential oil composition was analyzed at the SABS (South African
Valtcho D. Zheljazkov and Tess Astatkie
Japanese cornmint (Mentha canadensis L.) is a major essential oil crop grown in Asia, South America, and to a limited extent in eastern Europe. Japanese cornmint oil is the only commercially viable source for crystalline menthol. We hypothesized that the length of the distillation time (DT) will have an effect on Japanese cornmint essential oil content and composition. Therefore, the objective was to evaluate the effect of eight DTs (1.25, 2.5, 5, 10, 20, 40, 80, and 160 min) on essential oil content and composition. The essential oil content (0.43% to 1.06% range) reached maximum at 10 min DT; further increase in DT did not significantly increase essential oil content. The concentrations of alpha-pinene (0.14% to 0.76% range), beta-pinene (0.23–0.81), 3-octanal (0.19–0.34), limonene (0.69% to 1.53%), eucalyptol (0.06% to 0.12%), isopulegone (0.42% to 0.56%), and isomenthone (4.4% to 5.7%) were highest at 1.25 to 5 min DT and generally decreased to their respective minimums at 160 min DT. The concentration of menthone (4.3% to 6.3%) was highest at 1.25 min DT, decreased at 2.5 min, and was lowest at 10 to 160 min DT. The concentration of piperitone (0.98% to 1.27%) was lowest at 1.25 min DT and higher at 5 to 40 min DT compared with other DTs. The concentration of menthol (74% to 79%) was low at 1.25 min, then increased at 10 to 80 min DT, and reached a maximum at 160 min DT. Generally, the yield of most individual essential oil constituents was lower at 1.25 min DT relative to the other DT and reached maximum at 10 to 20 min DT. The yield of menthol was low at 1.25 to 2.5 min DT and rose at 5 min to 160 min DT. The results suggest that different DTs can be used to maximize recovery of certain constituents. Also, the results demonstrated that there are no oil yield gains after 20 min DT, which is much lower than the usual distillation time of 60 min or more. This study can be used as a reference when comparing reports in which different DTs were used.
Valtcho D. Zheljazkov, Tess Astatkie, and Ekaterina Jeliazkova
( Adams, 1979 ), and duration of distillation time ( Zheljazkov et al., 2012a , 2012b ) can affect Rocky Mountain juniper essential oil composition. However, there are no reports on variations of Rocky Mountain juniper essential oil year-round, from