Search Results

You are looking at 11 - 20 of 20 items for

  • Author or Editor: Tess Astatkie x
Clear All Modify Search
Free access

Valtcho D. Zheljazkov, Tess Astatkie, Thomas Horgan and S. Marie Rogers

Steam distillation of essential oil crops produces residual distillation wastewater that is released into the environment. This study evaluated the effects of three plant hormones [methyl jasmonate (MJ); gibberellic acid (GA3); and salicylic acid (SA)] at three concentrations and the residual distillation water from 15 plant species applied as foliar spray on biomass yields, essential oil content, and essential oil yield of Mentha ×piperita ‘Black Mitcham’ and Mentha spicata ‘Native’. Overall, the application of SA at 1000 mg·L−1 increased biomass yields of both species. More treatments influenced essential oil content in ‘Black Mitcham’ peppermint than in ‘Native’ spearmint. Application of MJ at 100 and 1000 mg·L−1, GA3 at 10 mg·L−1, SA at 10 or 100 mg·L−1, and distillation water of Achillea millefolium, Ammi majus, Artemisia absinthium, Cymbopogon flexuosus, Cymbopogon martinii, Chrysanthemum balsamita, and Hypericum perforatum increased the essential oil content of peppermint, whereas the oil content of spearmint was increased only by application of Monarda fistulosa distillation water. Application of MJ at 100 mg·L−1, SA at 100 mg·L−1, and A. absinthium, C. flexuosus, and C. balsamita distillation waters increased essential oil yields of peppermint, whereas the application of SA at 1000 mg·L−1 and distillation water of A. absinthium, Lavandula vera, and M. fistulosa increased oil yields of spearmint. This study demonstrated that the residual distillation water of some aromatic plant species may be used as a tool for increasing essential oil content or essential oil yields of peppermint and spearmint crops.

Free access

F. Christine Pettipas, Rajasekaran R. Lada, Robert Gordon and Tess Astatkie

Increasing temperature as a result of global climate change is expected to exert a great influence on agricultural crops, possibly through effects on photosynthesis. Response to temperature of leaf gas exchange parameters of carrot (Daucus carota L. var. sativus) cultivars Cascade, Carson, Oranza, and Red Core Chantenay (RCC) were examined in a controlled growth room experiment. Leaf net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were measured at temperatures ranging from 15 to 35 °C at 370 μmol·mol-1 (CO2) and 450±20 μmol·m-2·s-1 PAR. The cultivars responded similarly to increasing temperature and did not differ in most photosynthetic parameters except gs. The PN increased between 20 and 30 °C, thereafter increasing only slightly to 35 °C. On average, increasing temperature from 20 to 30 °C increased PN by 69%. Carboxylation efficiencies (Ca/Ci ratio) ranged from 1.12–2.33 mmol·mol-1 while maximum PN were 3.25, 3.90, 5.49, 4.19 μmol·m-2·s-1 for Carson, RCC, Cascade, and Oranza, respectively. The E did not reach maximum at 35 °C while gs peaked at 30 °C and then decreased by 93% at 35 °C. The water use efficiency (WUE) decreased with an increase in temperature due to increases in both PN and E. The results indicate that increasing temperatures above the seasonal average (<20 °C) increases both PN and E up to 30–35 °C. An increase in photosynthesis due to an increase in temperature is expected to hasten growth. Carrots may be able to withstand a moderate increase in temperature.

Restricted access

Rizwan Maqbool, David Percival, Qamar Zaman, Tess Astatkie, Sina Adl and Deborah Buszard

The study examined the main and interactive effects of soil-applied fertilizers [nitrogen (N), phosphorus (P), and potassium (K)] from a 12-year (six production cycles) field experiment conducted at Kemptown, Nova Scotia (Canada). It also recommends the optimum rate for improved growth and harvestable yield of wild blueberry (Vaccinium angustifolium Ait.). The fertilizers were applied in a single application at the onset of shoot emergence in early spring of each sprout year at rates of 0, 12, 30, 48, and 60 kg·ha−1 N using urea (2000 only) or ammonium sulfate, 0, 18, 45, 78, and 90 kg·ha−1 P using triple super phosphate, 0, 12, 30, 48, and 60 kg·ha−1 K using potassium chloride. Response surface analysis of the data indicated that 35 kg·ha−1 N, 40 kg·ha−1 P, and 30 kg·ha−1 K were optimum for fruit production and maintaining stem lengths <20 cm, and resulted in an average of 54% more floral buds, 25% more berries per stem, and 13% greater yield than previous recommend rates of 20 kg·ha−1 N, 10 kg·ha−1 P, and 15 kg·ha−1 K. The higher fertilizers rates cost an extra $80/ha but increased net profits by $490/ha. Findings of this study could contribute toward better farm profitability in areas with similar growing conditions. They also suggest that modifications to existing fertilizer rates be made for Central Nova Scotia wild blueberry.

Free access

Rajasekaran R. Lada, F. Christine Pettipas, Steve Kyei-Boahen, Robert Gordon and Tess Astatkie

Genotypes and environmental parameters interactively act on plants and modify their yield responses through modifying photosynthetic processes. In order to optimize yield, it is critical to understand the photosynthetic behavior of the crop as altered by genotypes and environment. Leaf gas exchange parameters of carrot (Daucus carota L.) cultivars Cascade, Carson, Oranza, and Red Core Chantenay (RCC) were examined in response to various irradiances, fertility levels, moisture regimes, and to elevated CO2 concentrations. Leaf net photosynthetic rate (PN), stomatal conductance (gs), and transpiration rate (E) were measured. Cultivars responded similarly to increasing PAR and CO2 concentrations and did not differ in photosynthetic parameters. Increasing PAR from 100 to 1000 μmol·m-2·s-1 increased PN, which did not reach saturation. The gs and E increased to a peak between 600 and 800 &#956;mol·m-2·s-1, then rapidly declined, resulting in a sharp increase in water use efficiency (WUE). Increasing CO2 concentrations from 50 to 1050 μmol·mol-1 increased PN until saturation at 650 μmol·mol-1. The gs and E increased to a peak at 350 μmol·mol-1 and then declined. WUE increased linearly with increasing CO2. Carrots exposed to drought over a period of 5 days decreased PN and E. The PN decrease was cultivar specific. Nutrient concentrations of 0 to 400 ppm gave a similar pattern of decrease for PN, E, and gs. Treatment of 50 ppm had the highest PN, E, and gs. The WUE generally increased with increasing nutrient concentration.

Free access

Valtcho D. Zheljazkov, Tess Astatkie, Thomas Horgan, Vicki Schlegel and Xavier Simonnet

Sweet sagewort, also known as sweet wormwood (Artemisia annua L.), contains essential oil and other natural products. The objective of this study was to evaluate the effect of eight different distillation times (DTs; 1.25 minutes, 2.5 minutes, 5 minutes, 10 minutes, 20 minutes, 40 minutes, 80 minutes, and 160 minutes) on A. annua essential oil and its antioxidant capacity. Highest essential oil yield was achieved at 160-minute DT. The concentration of camphor (8.7% to 50% in the oil) was highest at the shorter DT and reached a minimum at 160-minute DT. The concentration of borneol showed a similar trend as the concentration of camphor. The concentrations of some constituents in the oil were highest at 2.5-minute DT (alpha-pinene and camphene), at 10 minutes (paracymene), at 20 minutes (beta-chamigrene and gamma-himachalene), at 80 minutes [transmuurola-4(15),5-diene and spathulenol], at 80- to 160-minute DT (caryophylene oxide and cis-cadin-4-en-ol), or at 160-minute DT (beta-caryophyllene, transbeta-farnesene, and germacrene-D). The yield of individual constituents reached maximum at 20- to 160-minute DT (camphor) at 80- to 160-minute DT [paracymene, borneol, transmuurola-4(15),5-diene, and spathulenol], or at 160-minute DT (for the rest of the oil constituents). DT can be used to attain A. annua essential oil with differential and possibly targeted specific chemical profile. The highest antioxidant capacity of the oil was obtained at 20-minute DT and the lowest from the oil in the 5-minute DT. This study suggests that literature reports on essential oil content and composition of A. annua could be compared only if the essential oil was extracted at similar DTs. Therefore, DT must be reported when reporting data on essential oil content and composition of A. annua.

Free access

Valtcho D. Zheljazkov, Charles L. Cantrell, Mateus Augusto Donega, Tess Astatkie and Bonnie Heidel

Podophyllotoxin is used for the production of the anticancer drugs etoposide, etopophos, and teniposide. Currently, podophyllotoxin is extracted from the Himalayan mayapple (Podophyllum hexandrum Royle). Some junipers and other species also contain the same natural product and have been explored as a domestic source for this compound. The objective of this study was to screen junipers in the Big Horn Mountains in Wyoming for podophyllotoxin. Twenty junipers (18 accessions of Juniperus horizontalis Moench. and two accessions of J. scopulorum Sarg.) were sampled in Mar. 2012 and analyzed for podophyllotoxin. Podophyllotoxin concentration in the samples varied from 0.058% to 0.673% with five accessions having podophylloxin concentration above 0.5%. This study demonstrated wide variation of podophyllotoxin in J. horizontalis and J. scopulorum in the Big Horn Mountains. Some of the accessions had greater than 0.5% podophyllotoxin making them a feasible source for podophyllotoxin extraction.

Free access

Valtcho D. Zheljazkov, Thomas E. Horgan, Tess Astatkie, Dolores Fratesi and Charles C. Mischke

The aquaculture industry generates significant nutrient-rich wastewater that is released into streams and rivers causing environmental concern. The objective of this controlled environment study was to evaluate the effect of waste shrimp water (SW), vermicompost (VC), at rates of 10%, 20%, 40%, and 80% by volume alone or in combination with SW, controlled-release fertilizer (CRF), and water-soluble fertilizer (WSF) on bell peppers (Capsicum annuum L.) cv. X3R Red Knight. Application of VC at 80% or SW alone increased yields relative to unfertilized control. Combined applications of VC and SW increased yields compared with VC alone. Overall, total yields were greatest in the chemical fertilizer treatments (CRF and WSF) and least in the unfertilized control. SW and VC increased growth medium pH relative to the unfertilized control or to the chemical fertilizer treatments. In pepper fruits, the greatest nitrogen (N) content was found in the CRF treatment, although it was not different from VC at high rates or WSF treatments. Phosphorus concentration in peppers was greatest in the CRF treatment, less in all VC or SW treatments, but not different from unfertilized control or WSF treatment. Iron, magnesium (Mg), and zinc concentrations in peppers were greatest in CRF treatment but not different from control or WSF treatments. Overall, N accumulation in peppers was negatively correlated to growth medium pH and calcium (Ca); phosphorus (P) in peppers was negatively correlated to growth medium pH, Ca, and sodium (Na), whereas potassium (K) in peppers was negatively correlated to growth medium P, Mg, and Na. Results indicated: 1) SW may not be a viable pepper nutrient source; (2) SW can provide a similar nutrient supply as VC; and (3) chemical fertilizers can provide higher pepper yields compared with SW or VC alone or in combination.

Free access

Valtcho D. Zheljazkov, Tess Astatkie, Santosh Shiwakoti, Shital Poudyal, Thomas Horgan, Natasha Kovatcheva and Anna Dobreva

Garden sage (Salvia officinalis L.) is a medicinal, culinary, ornamental, and essential oil plant with a wide range of ecological adaptation. Garden sage essential oil traditionally is extracted by steam distillation from the above-ground biomass and has widespread applications as an aromatic agent in the food and pharmaceutical industries as well as in perfumery and cosmetics. The hypothesis of this study was that the steam distillation time (DT) may significantly affect essential oil yield and composition of garden sage and, therefore, DT could be used as a tool to obtain oil with different composition. Therefore, the objective was to evaluate the effect of various steam DTs (1.25, 2.5, 5, 10, 20, 40, 80, and 160 minutes) on garden sage oil yield and composition. Most of the oil in the garden sage dry herbage was extracted in 10-minute DT; extending DT up to 160 minutes did not significantly increase oil yields. Overall, 39 oil constituents were identified in the garden sage essential oil. Fourteen oil constituents with the highest concentration in the oil were selected for statistical analyses. Monoterpenes represented the major percentage (58.2% to 84.1%) of oil composition followed by sesquiterpenes (4.0% to 16.1%) and diterpenes (0.3% to 7.6%). Overall, the monoterpene hydrocarbons (α-pinene, camphene, β-pinene, myrcene, and limonene) were eluted early in the steam distillation process, which resulted in their high concentration in the oil at 5- to 10-minute DT and relatively low concentrations in the oil obtained at 160-minute DT. In general, the concentration of sesquiterpenes (β-caryophyllene, α-humulene, and verdifloral) increased with increasing duration of the DT and reached their respective maximum concentrations in the oil at 160-minute DT. The relative concentrations of major constituents, camphor and cis-thujone, in the oil obtained at 2.5-minute DT were higher than in the oils obtained at longer DT. Therefore, if oil with high concentrations of camphor and cis-thujone is desirable, garden sage dried biomass ought to be steam distilled for 2.5 to 5 minutes and the oil collected. If oil with a high concentration of monoterpene hydrocarbons and a high concentration of oxygenated monoterpenes is desirable, then garden sage should be distilled for 20 minutes. If oil with a high concentration of the diterpene manool is desirable, then garden sage should be steam-distilled for 80 minutes. If oil with a high concentration of sesquiterpenes is desirable, then garden sage should be steam-distilled for 160 minutes. The duration of steam distillation can be used as an economical method to obtain garden sage oil with a different chemical composition. The regression models developed in this study can be used to predict garden sage oil yield and composition distilled for various amounts of time and to compare literature reports in which different durations of DT were used.

Free access

Valtcho D. Zheljazkov, Santosh Shiwakoti, Tess Astatkie, Ivan Salamon, Daniela Grul'ová, Silvia Mudrencekova and Vicki Schlegel

Cumin (Cuminum cyminum L.) is an important essential oil (EO), medicinal, and spice plant from family Apiaceae. Cumin seed EO has wide applications in the food, liquor, pharmaceutical, and aromatherapy industries, and is extracted via steam or hydrodistillation of either whole or ground seed. The hypothesis of this study was that by capturing oil eluted at different timeframes during the hydrodistillation process (HDP), we could obtain oils of differential composition and bioactivity. The objective was to evaluate the EO fractions captured at different timeframes of the HDP. In this study, we collected nine different EO fractions following nine hydrodistillation time (HDT) frames: 0–2, 2–7, 7–15, 15–30, 30–45, 45–75, 75–105, 105–135, and 135–165 minutes. In addition, continuous HDT of 165 minutes was conducted as a control and the complete cumin seed oil was collected at the end of this time. HDT significantly affected the concentrations of the following constituents in the oil (as percentage of total oil): α-pinene (0.2% to 2.1%), β-pinene (5% to 35.8%), mycrene (0.3% to 1.7%), para-cymene (12.0% to 26.4%), γ-terpinene (4.8% to 25.9%), cumin aldehyde (3.8% to 51.1%), α-terpinen-7-al (0.2% to 11.2%), and γ-terpinen-7-al (1.3% to 13.1%). Some of the constituents were eluted early in the HDP and were highest in the oil fraction collected at the beginning of the HDP, others were highest in the fractions collected midway in the HDP, and another group of constituents were eluted later and were the highest in the oil fractions collected during the last HDT (135–165 minutes). Due to their altered chemical composition, the oil fractions expressed different antioxidant capacities; the one eluted at 105–135 minutes HDT had the greatest oxygen radical absorbance capacity (ORAC) values. The ORAC values were positively correlated to the concentration of cumin aldehyde (0.962), α-terpinene (0.889) and γ-terpinene (0.717), which suggest that these compounds in cumin oil may be responsible for the measured antioxidant capacity. This study demonstrated that cumin oil with dissimilar chemical profile and antioxidant activity could be obtained from the same batch of seed by capturing oils at different timeframes during the same HDP. The resulting products (EO fractions) could have diverse industrial, medical, and environmental applications. The method for cumin seed grinding and EO extraction described in this study could be used by industry to reduce energy inputs and oil losses, and for fast oil extraction.

Free access

Santosh Shiwakoti, Henry Y. Sintim, Shital Poudyal, Jennifer Bufalo, Charles L. Cantrell, Tess Astatkie, Ekaterina Jeliazkova, Lyn Ciampa and Valtcho D. Zheljazkov

Japanese cornmint, also known as menthol mint (Mentha canadensis L. syn M. arvensis L.), is an essential oil crop cultivated in several countries in Asia and South America. The plant is currently the only commercially viable source for natural menthol as a result of the high concentration of menthol in the oil compared with other crops. The hypothesis of this study was that harvesting at regular intervals within a 24-hour period would have an effect on essential oil concentration and composition of Japanese cornmint grown at high altitude in northern Wyoming. Flowering plants were harvested every 2 hours on 7 to 8 Aug. and on 14 to 15 Aug. and the essential oil was extracted by steam distillation and analyzed by gas chromatography–mass spectroscopy (GC-MS). The effects of harvest date (Harvest 1 and Harvest 2) and harvest time (12 times within a 24-hour period) were significant on oil concentration and yield of menthol, but only harvest date was significant on the concentration of menthol in the oil. The interaction effect of harvest date and harvest time was significant on water content and on the concentrations of menthol and menthofuran in the oil and on the yield of limonene, menthol, and menthofuran. Overall, the oil concentration in grams per 100 g dried material for the two harvests (1.26 and 1.45, respectively), the concentration of menthol in the oil (67.2% and 72.9%, respectively), and menthol yield (1066 to 849 mg/100 g dried biomass) were higher in plants at Harvest 2 as compared with plants at Harvest 1. The oil concentration was higher in plants harvested at 1100 hr or at 1300 hr and lowest in the plants harvested at 1500 hr. Menthol yield was the highest in plants harvested at 1300 hr and lowest in the plants harvested at 0700 hr, 1900 hr, or at 0300 hr. This study demonstrated that harvesting time within a 24-hour period and harvest date (maturity of the crop) may affect essential oil concentration and composition of Japanese cornmint grown at high altitude in northern Wyoming.