et al., 2004a , 2004b ; Yassen et al., 2003 ) on sweet basil productivity and oil composition. Sulfur is another macronutrient with important functions in plants. It is a part of plant proteins as a component of the amino acids cysteine and
Valtcho D. Zheljazkov, Charles L. Cantrell, M. Wayne Ebelhar, Dennis E. Rowe, and Christine Coker
J. Touss, J. Lloveras, and A. Romero
Ethephon was applied at 0, 625, 1250, 1875, and 2500 m·gliter-1 in 2 consecutive years to `Arbequina' olive trees to determine its effect on fruit removal with mechanical harvesting and on fruit oil composition. Ethephon increased the mechanical harvesting efficiency by 20%. Ethephon at 1250 and 1875 mg·liter-1 were the optimum treatments, resulting in 63% and 66% of the olives being mechanically harvested, respectively, with a preharvest olive drop of 10% and 11%. Leaf drop (4.6 and 4.8 kg/tree fresh weight, respectively) at these concentrations did not reduce flowering the following year. Oil acidity, peroxide value, and fatty acid composition were affected little by ethephon and the values observed were within the range of normal annual variation. These results suggest that ethephon did not modify oil quality and that its use on traditionally pruned `Arbequina' trees is not economically justifiable. Chemical name used: (2-chloroethyl)phosphonic acid (ethephon).
Giuliana Mulas and Lyle E. Craker
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.
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.
Thomas Gradziel, Noreen Mahoney, and Ashraf Abdallah
Genetic differences were observed in levels of aflatoxin production following controlled inoculations of California almonds [Prunus dulcis (Mill.) D.A. Webb, syn. P. amygdalus, Batsch.; P. communis (L.) Arcangeli, non Huds.]. Genetic variation was also observed in kernel oil composition, and in susceptibility to Aspergillus flavus Speare as indicated by rate of mold expansion on the surface of cut kernels. Several almond lines resulting from the introgression of peach [P. persica (L.) Batsch] germplasm had very low aflatoxin levels relative to commercial cultivars tested. Peach-derived almond breeding lines and cultivars also produced some of the highest oil quality as determined by the proportion of oleic acid, and by the oleic to linoleic acid balance. The proportion of linoleic acid to total oil ranged from 16% to almost 30%. No correlations were detected between aflatoxin production in inoculated almond kernels and either kernel oil composition or mold growth rate on injured kernel tissue.
Valtcho D. Zheljazkov, Vasile Cerven, Charles L. Cantrell, Wayne M. Ebelhar, and Thomas Horgan
; Zheljazkov and Margina, 1996 ; Zheljazkov and Nielsen, 1996 ). Nitrogen is one of the most important modifiers of peppermint productivity and oil composition ( Clark and Menary, 1980c ; Jeliazkova et al., 1999 ; Kothari and Singh, 1995 ; Mitchell and
Valtcho D. Zheljazkov, Tess Astatkie, Thomas Horgan, and S. Marie Rogers
oil from the spearmint and peppermint from each pot was extracted with steam distillation as described previously ( Zheljazkov et al., 2010a , 2010b ), and the essential oil was collected and measured. The essential oil composition of each sample was
Laurence Sistrunk, Dan Chapman, and J. Benton Storey
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.
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