A 500 liter (130 gallon) stainless steel steam distillation unit has been built to extract volatile essential oils from aromatic plants. A 1.5 m × 0.75 m dia. steam vessel (hydrostatically tested @ 125 psi) serves as the distillation tank. Low pressure or high pressure steam is supplied by a diesel fuel fired boiler of 10 horsepower. The steam vessel can hold peppermint from plots of 25 m2 and extract approximately 100 ml of essential oil per distillation. The size of the tub was designed to provide oil in sufficient quantity for industrial evacuation or for pesticide residue analysis. Following the distillation, the vessel can be disconnected from the cold-water condenser and rotated on swivels to a horizontal position, permitting easy removal and re-filling of plant material. The entire extraction unit (vessel, condenser, boiler and oil collector) is suitable for mounting upon a trader, making it transportable to commercial farms or research stations. The extraction of peppermint and spearmint oils using this new system will be presented.
Four cultivars of pecan [Carya illinoinensis (Wangenh.) K. Koch] were selected for the study (`Cheyenne', `Mohawk', `Pawnee', and `Osage'). The influence of total climatic heat units, during nut filling, on nut quality was compared from 14 geographic locations over a 3-year study. Nut quality parameters included nut size by weight, kernel percentage by weight, kernel color by Hunter Color Difference Meter, fatty acid profile by GC, and total oil by NMR. Nuts were harvested at shuck split, dried to 3% moisture, and stored at –20C prior to analysis. Monounsaturated fatty acids (MUFA) and total oil increased, and polyunsaturated fatty acids (PUFA) decreased in `Mohawk' 2 out of 3 years with increased heat units. Fatty acids in `Pawnee' responded the same as in `Mohawk' in 1992, but were variable in 1991. In 1993, `Pawnee' kernel whiteness and total oil decreased with increased heat units. Higher heat units caused the testas of `Cheyenne' to be darker in all 3 years. MUFA of `Cheyenne' increased with increased heat units 1 out of 3 years. The PUFA content of `Cheyenne' decreased with increased heat units in 1993. `Osage' showed a reversal of MUFA and PUFA with increased heat units. High negative correlation between oleic and linoleic acid were obtained for all cultivars.
To determine the mode of inheritance of citral, linalool, methylchavicol, and methylcinnamate in basil, controlled crosses were made between chemotypes rich in each of these constituents. Four stable Ocimum basilicum populations selected for high methylcinnamate (79%), methylchavicol (95%), linalool (82%), and citral (65%) respectively, served as parents. Crosses were made using chemotypes rich in terpenes (linalool × citral), in phenylpropanoids (methylchavicol × methylcinnamate), and a third that combines chemotypes from both biosynthetic pathways (linalool × methylchavicol). True hybrids were selfed in isolation and one hundred F2 plants were analyzed for their oil composition. The parents, the F1 hybrids and the F2 generation of all plants were evaluated in a field trial under identical environmental conditions. Plants were harvested at full flowering, and dried at 380 °C. Identification of essential oil constituents were confirmed by GC/MS. The F2 segregation data for each major oil constituent trait will be examined by c2 analysis tests. Preliminary results indicate that methylcinnamate segregates in a 3:1 ratio, and is a dominant major gene. In the two crosses using methylcinnamate chemotype as a female parent, the F2 population segregates in 80:22 and 65:28 methylcinnamate:non-methylcinnamate plant types, with P = 0.42 and 0.25 and c2=0.64 and 1.29, respectively. Analysis of the other crosses are being processed, evaluating qualitative and quantitatively the presence or absence of each constituent in their F2 population.
Preclimacteric `Bartlett' pears (Pyrus communis L.) were dipped for 3 min in either corn (Zea mays L.) or soybean [(Glycine max (L.) Merrill] oil emulsion immediately after harvest and stored at 0 °C. Untreated control fruit developed higher percentages of senescent scald, core breakdown, and decay after 15 weeks storage. Both treatments inhibited senescent scald, core breakdown, and decay in a similar and concentration dependent manner. Complete control of senescent scald and core breakdown was achieved by emulsions at 5% and 10%, and of decay by emulsion at 10%. Compared with controls, emulsion treatments delayed and reduced internal ethylene accumulation and volatile production in early storage and increased them in late storage. Compared with controls, fruit treated with oil contained similar levels of internal O2 and CO2 in early storage and higher CO2 and lower O2 in late storage. While control fruit lost commercial value after 15 weeks at 0 °C plus 5 days at 20 °C, oil-treated fruit exhibited normal color change, and had higher soluble solids, titratable acidity, and volatile production. Microscopic examination revealed that emulsion-treated fruit had a continuous surface film conforming to the contour of the fruit.
Dormant `Georgia Belle' peach [Prunus persica (L.) Batsch.] trees were sprayed in early February 1992 with single applications of 0%, 2.5%, 5.0%, 10.0%, or 20.0% (v/v) crude soybean oil. `Redhaven' trees were sprayed in February 1993 with single applications of 0%, 2.5%, 5.0%, 10.0%, or15% degummed soybean oil. Additional treatments of two applications of 2.5% or 5.0% oil were included each year. Both crude and degummed soybean oil treatments interfered with escape of respiratory CO2 from shoots and increased internal CO2 concentrations in shoots for up to 8 days compared to untreated trees. Respiration rates, relative to controls, were decreased for 8 days following treatment, indicating a feedback inhibition of respiration by the elevated CO2. Thus, an internal controlled atmosphere condition was created. Ethylene evolution was elevated for 28 days after treatment. Flower bud development was delayed by treating trees with 5% crude or degummed soybean oil. Trees treated with 10% crude or degummed soybean oil bloomed 6 days later than untreated trees. Repeated sprays of one half concentration delayed bloom an additional four days in 1992, but < 1 day in 1993 compared to a single spray of the same total concentration. Application of soybean oil caused bud damage and reduced flower bud density (number of flower buds/cm branch length) at anthesis. In a trial comparing petroleum oil and degummed soybean oil, yields of trees treated with 6% or 9% soybean oil were 17% greater than the untreated trees and 29%more than petroleum treated trees. These results suggest that applying soybean oil delays date of peach bloom and may be used as a bloom thinner.
have significantly greater essential oil and 2-methyl-5-propan-2-ylphenol (carvacrol) yields than the currently offered commercial alternatives. These two new cultivars were developed to provide good field performance, upright growth habit, to
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.
Fruit set is a key component of essential oil yield from fennel (Foeniculum vulgare Mill.) under Tasmanian conditions. Fruit set in commercial crops is often low, possibly due to incomplete pollination. Fennel flowers are strongly protandrous and a series of flowers must be produced to ensure pollination. The hypothesis tested was that decreasing stand density increases the number of lateral branches, thereby increasing the number of higher order umbels and thus increasing the overlap between the periods of pollen production and stigma receptivity. A field trial was used to examine the number of umbels of each order produced under stand densities of 4, 12, 25, 50 and 100 plants/m2. Stand density influenced the ratio of pollen producing to pollen receptive umbels and stand densities of 50 and 100 plants/m2 showed a distinct imbalance between pollen production and stigma receptivity. The data collected supported the hypothesis and it is probable that, in commercial crops, fruit set is being reduced by a lack of synchrony between pollen production and stigma receptivity. The highest stand density tested reduced total oil production. We therefore recommend the inclusion of low stand-density strips within standard-density commercial crops.
Plants of rosemary [Rosmarinus officinalis L. (Lamiaceae)] were grown in pots containing a soilless (1 sphagnum peat:1 perlite) or soil-based (1 sphagnum peat: 1 perlite:1 field soil) growing medium and fertilized with either 12N-5.2P-12.5K controlled-release fertilizer (CRF) at 9.0 g/pot; constant liquid fertilization (LF) with 20N4.3P-16.7K at 150 mg N/liter; constant LF at 150 mg N/liter, plus CRF at 4.5 g/pot; weekly LF at 150 mg N/liter; or weekly LF at 150 mg N/liter, plus CRF at 4.5 g/pot. Constant LF plus CRF generally reduced plant height and depressed shoot fresh weight relative to other fertilizer regimes. Essential oil content was highest in plants receiving weekly LF. Plants grown in the soil-based mix were shorter, shoot fresh and dry weight tended to be lower, and essential oil yield was higher when compared to plants grown in the soilless mix. Satisfactory growth was obtained in both media when rosemary plants were fertilized with 12N-5.2P-12.5K CRF at 9.0 g/pot or weekly LF with 20N<.3P-16.7K at 150 mg N/liter.
The growth rate of vetiver grass [Vetiveria zizanioides (L.) Nash (Graminales: Poaceae)], roots, and oil distribution were evaluated in an 8-month field study. The amount of vetiver oil present in the root system increased with each sampling date. In December, the final sampling period, mean root weight increased 520% from the previous sampling period (October). At the end of the study, root growth measured over 2 m long and 25 cm wide and weighed 0.48 kg (dry weight). In addition, a laboratory study was conducted to determine if the roots of vetiver grass when used as mulch, are effective against Formosan subterranean termites, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). In past studies, chemical components in the roots of this grass were shown to be effective repellents and toxicants to Formosan subterranean termites. In the present study, the 25% vetiver root mulch treatment proved to decrease tunneling activity and wood consumption and increase termite mortality. These results provide preliminary evidence that vetiver roots may have use as an additive to garden mulches against termites.