( Boira and Blanquer, 1998 ). In fennel, there were cultivar-specific responses to planting dates and, as expected, cultivar-specific chemical profiles in the essential oils ( Bowes and Zheljazkov, 2005 ). Anemopsis californica is collected throughout
Andrea L. Medina-Holguín, Sandra Micheletto, F. Omar Holguín, Jaime Rodriguez, Mary A. O'Connell, and Charles Martin
Orapin Kerdchoechuen, Natta Laohakunjit, Sasathorn Singkornard, and Frank B. Matta
and may be contaminated with undesirable pesticides ( Sighamony et al., 1990 ). There is a need for use of botanical pesticides such as plant essential oils, which are environmental friendly ( Asawalam et al., 2008a ). Essential oils are naturally
D.M. Obenland, D.A. Margosan, L.G. Houck, and L.H. Aung
Release, localization, and concentration of essential oils in chilling-injured and noninjured lemon [Citrus limon (L.) Burm.] fruit were investigated to enhance understanding of how chilling injury (CI) occurs in lemon. CI in the form of moderate to severe pitting of the flavedo was initially apparent after 3 weeks at 1 °C, followed by a gradual increase in severity until termination of the experiment after 7 weeks at 1 °C. Curing the fruit at 15 °C for 1 week before cold treatment greatly reduced the severity of CI. Release from the fruit of d-limonene, a major component of essential oil in lemon, increased with increasing amounts of CI. The enhancement of d-limonene release, however, lagged behind the development of CI. Studies of the internal anatomy of the flavedo using confocal microscopy indicated that essential oils were abundantly present inside the oil gland and in oil bodies outside the gland. Chilling-injured flavedo exhibited no obvious disruption of either the oil glands or the oil bodies. Extraction and quantification of d-limonene from chilling-injured and noninjured flavedo indicated that similar amounts of oil were present in the tissue, regardless of injury. Damage to the flavedo after 3 weeks at 1 °C was noted in the form of flattened or collapsed cells between the top of the gland and the epidermis, whereas collapse of the oil gland only was observed in later stages of injury development.
Jason McAfee and Curt Rom
Pesticides and alternative fruit thinners are needed for certified organic fruit growers. Transient reductions in photosynthesis (Pn) have proven an effective technique for fruit thinning. Pesticides can be detrimental to plant growth by Pn reduction. This study was developed to measure plant response to foliar applications of essential oils at 2% concentrations. Treatments were applied to vegetative apple trees grown under controlled environment conditions to study photosynthetic effects. There was no significant effect on Pn for treatments; however, clove oil was very phytotoxic and defoliated all trees in this study. Cinnamon oil and cedarwood oil significantly decreased evapotranspiration and stomotal conductance 1 day after treatment. Differences in plant growth were not significantly different for all treatments excluding clove oil. Studies on concentration effects may determine horticultural usefulness of these compounds.
Berry fruits such as blackberries (Rubus sp.) and blueberries (Vaccinium corymbosum L.) are highly perishable after harvest. In addition to rapid deterioration in quality, they are also very susceptible to microbial invasion. The shelf life of these berries is usually terminated by decay. Several natural antimicrobial compounds derived from essential oils of plants were studied for their efficacies in inhibiting decay and extending shelf life of berry fruits. The severity of decay in blackberries and blueberries stored at 10 °C was significantly reduced by treatment with thymol. Treatments with menthol or eugenol also suppressed the fungal growth, but to a lesser extent. All of these three natural antimicrobial compounds extended shelf life of blackberries and blueberries as compared to the control. Berries treated with thymol, menthol, or eugenol also maintained better fruit quality with higher levels of sugars, organic acids, and oxygen radical absorbance capacity than the untreated fruits. The effects of these natural antimicrobial agents on the quality and shelf life of other fruits will be investigated.
Hanah T. Rheay, Kevin Lombard, Catherine Brewer, and F. Omar Holguin
their hybrids include Amalia, Latir, Medusa (or Multihead), Neo-1, Sabro, and Zappa ( CLS Farms, n.d. ; Jones, 2018 ; Santa Fe Brewing Co., n.d. ). Phytochemicals of interest include bittering acids and essential oils for their brewing properties as
J.A. Plummer, J. Wann, J.A. Considine, and Z. Spadek
Boronia megastigma is cultivated or picked from natural stands in Western Australia for the production of essential oil. Boronia absolute is extracted from the highly perfumed flowers. It is currently valued at between US$4000 and US$7000 per kilogram, and world consumption for perfumery is about 1 tonne. The variation in essential oil composition within and between populations has indicated considerable variation in oil components. Some individuals have high β-ionone and low levels of pinenes. Principle components analysis indicated that the content of β-ionone and dodecyl acetate were tightly linked, as were the monoterpenes, α-pinene, β-pinene, and, to a lesser extent, limonene. Separate linkages between the desirable oil components (β-ionone and dodecyl acetate) and the undesirable components (α-pinene, β-pinene, and limonene) will facilitate selection of plants to be used in oil production.
Renee G. Murray and James E. Simon
Essential oil content of Ocimum basilicum, cv. sweet basil, increases with plant maturity. The increase in essential oil content may correspond to the formation of glandular trichomes during leaf expansion. Greenhouse grown plants were harvested every 2 weeks. Leaves were grouped according to size, examined with a stereo microscope, and trichome densities compared. Results indicate that trichome formation continues throughout leaf expansion. In young basil plants, leaves ranged in size from 2-30cm2 Highest density (416 trichomes/cm2) occurred in leaves 2–6c m2. Prior to open bloom, leaves ranged in size from 2-49cm2. Highest density occurred in leaves 18-24c m2. In flowering plants leaves ranged in size from 2-34cm2, yet there was NSD in trichome density in leaves of different sizes. Analysis of the entire leaf surface of plants at each harvest showed the greatest density of trichomes in plants at full bloom (280 trichomes/c m2). All leaves have visible glandular trichomes. These glandular trichomes are most likely formed both prior to and during leaf expansion.
Denys J. Charles and James E. Simon
The curry plant [Helichrysum italicum (Roth) G. Don in Loudon ssp. italicum or H. angustifolium (Lam.) DC (Asteraceae)], a popular ornamental herb with a curry-like aroma, was chemically evaluated to identify the essential oil constituents responsible for its aroma. Leaves and flowers from greenhouse-grown plants were harvested at full bloom. Essential oils were extracted from the dried leaves via hydrodistillation and the chemical constituents analyzed by gas chromatography (GC) and GC/mass spectrometry. The essential oil content was 0.67% (v/w). Sixteen compounds were identified in the oil and included: neryl acetate (51.4%), pinene (17.2%), eudesmol (6.9%), geranyl propionate (3.8%),β-eudesmol (1.8%), limonene (1.7%), and camphene (1.6%). While the aroma of the curry plant is similar to that of a mild curry powder, the volatile chemical profile of the curry plant does not resemble that reported for commercial curry mixtures.
Mostafa Farajpour, Mohsen Ebrahimi, Amin Baghizadeh, and Mostafa Aalifar
accessions of Iranian A. millefolium are known to produce a wide variety of chemical compounds in the essential oils, with the most abundant components identified as chamazulene, germacrene D, sabinene, β-caryophyllene, p-cymene, bornyl acetate, camphene, β