Treatments of 0, 10, 20, 30, or 40% (v/v) refined (salad) or crude soybean oil or 0, 5, 10, 15, or 20% petroleum (dormant) oil at 0, 5, 10, 15, or 20% were sprayed until drip on `Smoothee' apple trees on 27 February 1991. The internal carbon dioxide concentration was elevated and the oxygen content reduced within one day in buds-twigs treated with oil and remained influenced for up to 12 days. All oil treatments delayed fruit bud development. The lowest tested concentration of soybean oil (either crude or refined) resulted in the greatest delay in bud development and the greatest delay in bloom (approximately 4 days). Crude soybean oil treatment resulted in less damage to flower buds than petroleum oil.
effect of temperature on apple pollen germination and pollen tube growth in styles; and 2) evaluate effects of liquid lime sulfur (LLS) + fish oil (FO) at different times after pollination on apple pollen germination, pollen tube growth, and fruit set in
Spurs of `Starkspur Delicious' trees were dipped in 0, 3, 6, 9 or 12% petroleum oil (dormant oil) or soybean oil emulsions on 26 January 1993. The spurs were cooled at 3C/hr until -9C or kept at 21C. After treatment, the flower buds on spurs were forced at 20C for 11 days and then dissected. The cambium and xylem of the spurs and the interior of the flower buds were rated for damage as indicated by browning. The experiment was repeated at the silver tip stage of buds (early March) except that treated spurs were exposed to 20C, -6C, or -9C. Neither the oil treatments nor low temperature exposure caused visual damage to flower buds or cambium in January. However, the oil treatments damaged flower buds at the silver tip stage (March). Neither petroleum or soybean oil caused visible damage to the xylem or cambium of the spurs.
A 3-year field study was undertaken to determine variations within ‘Moneymaker’ pecans [Carya illinoensis (Wang.) K. Koch] as to oil quantity and fatty acid content of the kernel. Individual pecan trees bore irregularly over the 3-year period. Yields were inversely correlated with nut wt and total oil content and directly with refractive index and potassium concentration of the mature kernel. Six fatty acids were found in kernel oil but only palmitic, oleic, and linoleic were correlated to yield.
Nuclear magnetic resonance (NMR) spectroscopy and magnetic resonance imaging (MRI) were used to detect petroleum-derived spray oils (PDSOs) in citrus seedlings and trees. The NMR spectrum of the phantom containing 10% (v/v) of a nC24 agricultural mineral oil (AMO) showed the resonance of the water protons at δ ≈ 5 ppm, while the resonance of the oil protons at δ = 1.3 to 1.7 ppm. The peak resolution and the chemical shift difference of more than 3.3 ppm between water and oil protons effectively differentiated water and the oil. Chemical shift selective imaging (CSSI) was performed to localize the AMO within the stems of Citrus trifoliata L. seedlings after the application of a 4% (v/v) spray. The chemical shift selective images of the oil were acquired by excitation at δ = 1.5 ppm by averaging over 400 transients in each phase-encoding step. Oil was mainly detected in the outer cortex of stems within 10 d of spray application; some oil was also observed in the inner vascular bundle and pith of the stems at this point. CSSI was also applied to investigate the persistence of oil deposits in sprayed mature Washington navel orange (Citrus ×aurantium L.) trees in an orchard. The trees were treated with either fourteen 0.25%, fourteen 0.5%, four 1.75%, or single 7% sprays of a nC23 horticultural mineral oil (HMO) 12 to 16 months before examination of plant tissues by CSSI, and were still showing symptoms of chronic phytotoxicity largely manifested as reduced yield. The oil deposits were detected in stems of sprayed flushes and unsprayed flushes produced 4 to 5 months after the last spray was applied, suggesting a potential movement of the oil via phloem and a correlation of the persistence of oil deposit in plants and the phytotoxicity. The results demonstrate that MRI is an effective method to probe the uptake and localization of PDSOs and other xenobiotics in vivo in plants noninvasively and nondestructively.
cut freesia by pulsing treatment J. Korean Soc. Hort. Sci. 41 135 138 Lambert, R.J.W. Skandamis, P.N. Coote, P.J. Nychas, G.J.E. 2001 A study of the minimum inhibitory concentration and mode of action of oregano essential oil, thymol and carvacrol Appl
Fennel (Foeniculum vulgare Mill.) is grown commercially in Tasmania for the production of a steam-distilled essential oil, which is high in trans-anethole. Often, only the generative canopy is harvested since this contains the bulk of the oil and further this oil is higher in anethole than oil from other parts of the plant. Regardless of whether the whole crop is forage harvested or the generative canopy alone is removed using a combine-harvester, the most efficient oil production occurs when the greatest proportion of the canopy is generative, giving maximum oil yield from a minimum of fresh weight to be processed. A trial was conducted to examine the relationship between stand density and the various yield components of fennel in order to predict the likely effect on yield of increasing stem density as the short term perennial crop matures. As for most crops, planting density and biomass yield are closely related and the optimum planting density was predicted using a mathematical model. The results suggest that an initial stand density of 10 to 12 plants/m2, in a square layout, would produce the greatest yield of essential oil per unit area by maximising the production of the generative canopy. This density also maximises the yield of oil relative to the weight of material to be distilled.
Biodegradable mulches made from kraft paper coated with polymerized (cured) vegetable oils were compared to black polyethylene mulches for promoting the growth of watermelon in northern Florida. Data from three spring growing seasons have been collected. Yields of watermelon planted on paper-soy oil and paper-linseed oil mulches were similar to those obtained for the control polyethylene mulches. This was the case where the paper-oil was cured before field application as well as when the paper-oil was applied to the field wet and curing took place in situ. Paper-oil mulches containing carbon black effectively blocked nutsedge growth, while nutsedge pierced and grew through the black polyethylene mulch. Degradation of the buried tucks were more rapid initially for paper-soy oil than paper-linseed oil mulch, but both lasted long enough to hold the mulch in place until spring harvests (≈2.5 months). In conclusion, paper coated with polymerized vegetable oil appears to be an effective substitute for polyethylene mulch for growing watermelon in Florida, although drawbacks include messiness in handling oily paper, slower application speeds, higher initial costs than polyethylene, and variability in rates of curing and degradation depending on soil and weather conditions.
Olive oil application during an approximate 10-day period following the time at which all drupelets within ‘Mission’ fig fruits had turned red was effective in stimulating fruit growth and maturity. Olive oil was found to yield ethylene, particularly when exposed to solar irradiation, and it is this degradation product that undoubtedly is the stimulative agent.
Essential oils were extracted from leaves, flowers, and stems of Ocimum basilicurn, O. kilimandscharicum, and O. micranthum by solvent extraction, hydrodistillation, and steam distillation for essential oil content and the oil analyzed by GC and GC/MS for composition. While the yield of essential oil was consistently higher from steam distillation than hydrodistillation, a similar number of compounds was recovered from both hydrodistillation and steam distillation. Though the relative concentration of the major constituents was similar by both methods, the absolute amounts were higher with steam distillation. Essential oil content and composition varied by plant species and plant part. Essential oil content was highest in flowers for O. basilicum and in leaves for O. micranthum. No significant differences were observed in essential oil yield and relative concentration of major constituents using fresh or dry samples and using samples from 75 g to 10 g of dry plant tissue. While minor differences between hydrodistillation and steam distillation were observed, both methods resulted in high yields and good recovery of essential oil constituents. Hydrodistillation is a more-rapid and simpler technique than steam and permits the extraction of essential oil where steam is not accessible.