Reduction In Oil Yield Research Articles

Melatonin Enhanced Drought Stress Tolerance and Productivity of Pelargonium graveolens L. (Herit) by Regulating Physiological and Biochemical Responses

As a type of abiotic stress, drought limits plant growth and productivity. The increased demand for the valuable essential oil extracted from geranium (Pelargonium graveolens L.) is mainly regulated by plant growth, which is adversely affected by drought. Melatonin (MT) has been used to enhance plant growth under various abiotic stresses, although its impact on overcoming drought stress in aromatic plants, including geranium, has not yet been investigated. In the current investigation, MT at 100 µM was applied at 100% (well-watered) or 50% (drought stress) field capacity to verify the role of MT in geranium under drought stress. Drought stress markedly reduced growth parameters, herb yield, and total chlorophyll content; however, MT alleviated these effects. The herb yield of the stressed plants was reduced by 59.91% compared to the unstressed plants, while this reduction was only 14.38% when MT was applied. In contrast, drought enhanced the essential oil percentage in geranium leaves. Despite the reduction in oil yield caused by drought, MT application mitigated this reduction and improved both oil yield and oil components. Moreover, the MT treatment enhanced the accumulation of total phenols, glutathione, and proline and improved the activity of ascorbate peroxidase, catalase, and glutathione reductase, resulting in the alleviation of drought-induced oxidative damage. Consequently, MT reduced both hydrogen peroxide and malondialdehyde accumulation by 71.11 and 48.30%, respectively, under drought, thereby maintaining the cellular structures’ integrity. Overall, this is the first report that reveals the ability of MT application to improve geranium oil yield and resistance to drought by enhancing the antioxidant defense system. The results enrich awareness regarding the potential benefits of the external application of MT and its roles that can help researchers to improve aromatic plants’ performance and productivity under drought stress.

Influence of the Absolute Pressure of the Extraction System on the Yield and Composition of Corymbia citriodora (Hook.) K.D.Hill and L.A.S.Johnson Leaf Essential Oil Extracted by Steam Distillation

This study aimed to evaluate the extraction of Corymbia citriodora (Hook.) K.D.Hill and L.A.S.Johnson essential oil by steam distillation under reduced pressure. Yield and composition of the essential oils obtained at different system pressures were analyzed. System pressure had a significant influence on essential oil yield, resulting in a reduction of 78.6% when the pressure was reduced from 690 Torr to 240 Torr. There were also changes in essential oil composition, with an increase in citronellol content (oxygenated monoterpene). However, the major compound (citronellal) remained at a high content in all tests. Regarding the extracted mass of the major compounds (citronellal, citronellol), there was a significant reduction for all when the system pressure was reduced. Although the reduction in the pressure of the system caused a reduction in oil yield, it was possible to carry out the steps of extraction and purification of the major compound simultaneously. Reduced pressure extraction may decrease process time, increasing its efficiency and reducing costs in the extraction of essential oils.

Effect of pedoclimatic variables on analytical and organoleptic characteristics in olive fruit and virgin olive oil

Due to the expansion of olive oil cultivation around the world and the increasing effects of climate change, Olea europaea (L:) cultivation must deal with ever higher temperatures and drought conditions, with productivity and virgin olive oil (VOO) quality issues. At the same time the demand for premium quality products with high nutraceutical value, chemical and organoleptic characteristics related to specific areas of cultivation is steadily rising. Within this framework a deep knowledge of the olive variety with regards to environment interaction is necessary to achieve VOO production and qualitative standards required by the market. Rainfed adult olives (cv Bosana) cultivated in five typical areas of north and central Sardinia (Italy) were the subject of a three-year study, with the aim to investigate the influence of pedoclimatic variability on olive and olive oil characteristics. Physical and chemical attributes of fruits (morphometric features, firmness, pH, titratable acidity, sugar content, moisture, and oil yield) and VOO (fatty acid and sensory profile) were analysed at harvest and related to monthly weather data (precipitation, maximum, average, and minimum temperatures) of the whole fruit development period and soil composition. Monthly maximum temperatures were the most relevant variables. However, the role of each meteorologic variable was specific per olive and olive oil parameters and their relevance varied according to the period of the season. An emblematic example is that the maximum temperatures during summer months reduced oil yield and improved oleic acid concentration, but during the following months, the same variable exerted an opposite effect. This suggests the presence of a maximum temperature threshold in the olive fruits, for lipogenesis processes. Meteoclimatic conditions during maturation were the principal element responsible for VOO sensory profile: high precipitation and low thermal amplitude promoted an attribute’s intensities.

Solar pyrolysis of biomass - part I: Volatile evolution mechanism

To study the volatile evolution mechanism during solar pyrolysis of biomass, willow pellets with thicknesses of 3 mm, 1 mm and 0.5 mm were used to investigate the dynamic pyrolysis characteristics at heat flux densities of 0.5 and 1.1 MW/m2. The results showed that the larger thickness significantly reduced oil yield (by 23%–35%) and increases gas yield (by 19%–20%), while increasing heat flux density showed a similar trend. These changes in solar pyrolysis behavior and product composition were governed by intra-particle secondary reactions due to the heat and mass transfer conditions. The evolution of heavy compounds (molecular weight ≥ 200 Da) was integrated into the volatile evolution mechanism of solar pyrolysis. Results showed the secondary reactions promoted the cracking, deoxygenation and condensation of sugars and phenolic species, and also led to the growth of condensed aromatic hydrocarbons. A novel dimensionless number (Bi∙Prmass) was proposed in this study to estimate the solar pyrolysis behavior of wood pellets. A smaller Bi∙Prmass indicates that the conversion process is dominated by primary pyrolysis, while a higher value indicates that it is dominated by intra-particle secondary reactions. Depending on the degree of condensation, a critical value of Bi∙Prmass around 0.1 was adopted in this study. This work can provide guidance about operating conditions optimization for solar gasification of biomass.

Exogenously Supplemented Proline and Phenylalanine Improve Growth, Productivity, and Oil Composition of Salted Moringa by Up-Regulating Osmoprotectants and Stimulating Antioxidant Machinery.

Salinity is linked to poor plant growth and a reduction in global food output. Therefore, there is an essential need for plant adaptation and mitigation of salinity stress conditions. Plants combat salinity stress influences by promoting a set of physiological, biochemical, and molecular actions. Tremendous mechanisms are being applied to induce plant stress tolerance, involving amino acid application. For evaluating the growth and productivity of Moringa oleifera trees grown under salt stress conditions, moringa has been cultivated under different levels of salinity and subjected to a foliar spray of proline (Pro) and phenylalanine (Phe) amino acids. Moringa plants positively responded to the lowest level of salinity as the leaves, inflorescences, seeds, and oil yields have been increased, but the growth and productivity slightly declined with increasing salinity levels after that. However, Pro and Phe applications significantly ameliorate these effects, particularly, Pro-treatments which decelerated chlorophyll and protein degradation and enhanced vitamin C, polyphenols, and antioxidant activity. A slight reduction in mineral content was observed under the high levels of salinity. Higher osmoprotectants (proline, protein, and total soluble sugars) content was given following Pro treatment in salted and unsalted plants. A significant reduction in oil yield was obtained as affected by salinity stress. Additionally, salinity exhibited a reduction in oleic acid (C18:1), linoleic (C18:2), and linolenic (C18:3) acids, and an increase in stearic (C18:0), palmitic (C16:0), eicosenoic (C20:2), and behenic (C22:0) acids. Generally, Pro and Phe treatments overcome the harmful effects of salinity in moringa trees by stimulating the osmoprotectants, polyphenols, and antioxidant activity, causing higher dry matter accumulation and better defense against salinity stress.

Canola Quality and Fatty Acids Composition as Influenced by Delayed Cropping and Late Season Drought Stress

To investigate the effects of drought stress and delayed planting on oil quality and fatty ‎acids composition of canola cultivars, a factorial split-plot test was conducted in a ‎randomized complete blocks design with three replications at Seed and Plant Improvement ‎Institute, Karaj, Iran for two years (‎2015-2017) ‎.Planting date at two levels of timely ‎planting (Oct. 27) and late planting (Nov. 27) and irrigation at two levels of normal ‎irrigation (control) and restricted irrigation from pod formation stage onwards were ‎considered the main factors. Canola cultivars including Kodiak, Traviata, Compass, ‎Diffusion, Mehr2, Elvise and Tassilo were the variables. The simple effects of planting date, ‎irrigation, and cultivar on all research parameters were significant. The interaction effect of ‎planting date × irrigation was significant on oil yield and oil content at the level of 5% and ‎in terms of linoleic and palmitic acids, and stomatal resistance, it was significant at the level ‎of 1%. The interaction effect of irrigation × cultivar was significant on palmitic acid, ‎glucosinolate and stomatal resistance at the level of 1%. Late season drought stress and late ‎planting dramatically reduced oil yield (58%), oil content (8%) and qualitative ‎characteristics of canola cultivars. Among the studied cultivars, Tassilo cultivar was ‎recommended for all conditions of this research with the seed yield (4407 kg ha-1), oil yield ‎‎(2007 kg ha-1), chlorophyll content (1.43 mg g-1fw), high oleic and linoleic fatty acids, as ‎well as low and standard erucic acid (0.41%) and glucosinolate (22.8 μmol g-1).‎

The Response of Growth and Yield of Canola Genotypes to Humic Acid Application in Different Plant Densities

To determine the effect of plant density and humic acid on canola yield, a 2-year field experiment was conducted as a factorial split-plot during the 2014–2016 cropping years. The factors included two humic acid levels (humic acid solution at 3/1000 [v/v] concentration and distilled water) and three plant densities (40, 60, and 80 plants per m2) in the main plots and six canola genotypes (Ahmadi, Okapi, Opera, Nafis, Karaj1, and SW102) in the subplot. The results showed a significant decrease in the grain and oil yield when plant density increased from 40 to 80 plants per m2, by 57 and 59%, respectively. The oil quality was also effected by the plant density, so the erusic acid and glucosinolate contents increased twofold at 80 plants m2. The grain and oil yield were significantly higher in plants treated with humic acid compared to controls, by 5.4 and 5.8%, respectively. Moreover, the foliar application of humic acid enhanced the oil quality of canola genotypes through a significant decrease in erusic acid and glucosinolate contents. However, there was no significant decreasing effect of humic acid on the density-induced yield loss and the oil yield reduction. Therefore, the increase in canola yield might be achieved by selecting the optimum density and improving the nutritional condition of the soil.

Drought stress in sunflower causes inhibition of seed filling due to reduced cell‐extension growth

AbstractCultivation of sunflower (Helianthus annuus L.) as one of the most important oil crops is of great importance, especially with focus on drought tolerance under the current climate change. Less precipitation and increasing temperatures lead to more regions with drought problems. In a container experiment, with two different sunflower cultivars, drought stress of 40% water‐holding capacity was applied at the seed‐filling phase and compared to a control group with regular irrigation to 70% water‐holding capacity. Four intermediate harvests during the seed‐filling phase and a final harvest at maturity were conducted. During the seed‐filling phase, sugar and α‐amino‐acid concentrations of seeds were not reduced by drought stress. Thus, assimilate availability was sufficient, pointing to no source limitation of seed development. The DNA content of the seeds was also not affected and pointed to no limitation of cell division. However, 40 days after flowering a reduction of cell extension was found. Consequently, a sink limitation occurred under drought stress. At final harvest, seed yield was significantly reduced under drought stress due to a lower single seed weight, whereas seed number per plant was unaffected. Oil concentration was not reduced by drought stress. Thus, oil synthesis did not limit oil yield. Consequently, a reduced oil yield under drought stress during the seed‐filling phase was caused by a lower seed weight, which resulted from a decreased cell extension.

Investigating of zeolite role in modifying the effect of drought stress in hemp: Antioxidant enzymes and oil content

Hemp is one of the industrial plants so that its oil is extracted from its grains and its quality and quantity are affected by abiotic stresses, especially water deficit. In order to study the physiological and biochemical responses of hemp to drought stress and zeolite application, a two-year experiment was performed in the experimental field of Shahrekord University (Shahrekord, Iran). Four levels of irrigation including severe stress, moderate stress, mild stress and well-watered (40 %, 60 %, 80 % and 100 % of crop water requirement, respectively) and 3 rates of zeolite clinoptilolite application including 0, 5 and 10 t ha−1 during growth season in 2014 and 2015 were studied as split plot.Water deficit reduced the morphological characteristics, chlorophyll content, dry matter and oil yield, and increased carotenoids content, antioxidant enzymes and oil content. The percentage of dry matter and oil yield reduction was improved with zeolite application, and the lowest percentage of dry matter and oil yield reduction compared to control was obtained from 10 t ha−1 zeolite under mild stress. Zeolite also greatly kept the process of antioxidant enzymes close to suitable conditions and reduced their activity, especially under mild stress. Thus, zeolite application reduced the negative impact of water deficit on these traits in hemp. It seems that 10 t ha−1 zeolite under mild stress conditions increases the threshold of hemp perception of water deficit and the activity of its defense systems has been reduced dramatically.

Spring safflower water use patterns in response to preseason and in-season irrigation applications

The deep root system of safflower (Carthamus tinctorius L.) is an important adaptive trait under rainfed conditions in semi-arid agriculture. Lower water requirements and ability to tolerate abiotic stresses make safflower a potential alternative crop for the Southern High Plains (SHP). However, information on water extraction patterns of safflower and its role in oil yield formation under center pivot irrigation system that keeps only the surface soil profile wet with frequent irrigations is limited. Therefore, a field experiment was conducted in a split-plot design at Clovis, New Mexico during 2012 and 2013 growing seasons to assess the soil water use patterns, evapotranspiration, and oil yield of two spring safflower cultivars under different preseason and in-season irrigation levels. Half of the experimental units received 164 and 153 mm of preseason irrigation in 2012 and 2013, respectively, while the other half remained unirrigated. Five in-season irrigation levels (I1–I5) ranging from 88 to 392 mm in 2012 and from 83 to 373 mm in 2013 were applied to preseason and no-preseason irrigation blocks. On average, safflower extracted 70 and 28 mm of stored soil moisture in the preseason and no-preseason irrigation treatments, which significantly increased evapotranspiration (ET), water use efficiency (WUE), and oil yield in preseason compared to no-preseason irrigation treatment. Average water extraction decreased with increasing level of in-season irrigation and a decline of 32, 27, and 25% in soil moisture at the end of the season compared to initial soil moisture were observed in I1, I3, and I5, respectively. Since, WUE was not much affected by in-season irrigation treatment in both years, limiting the in-season irrigation level to I4 can save 17% of irrigation with a corresponding 9% reduction in oil yield. The relatively smaller differences were observed for water extraction and WUE among the cultivars. Overall, safflower was able to use preseason irrigation water more efficiently in semi-arid SHP. Growers can pre-irrigate safflower and reduce its in-season irrigation to allocate more water to high water requirement traditional-crops such as corn.

Ripening Indices, Olive Yield and Oil Quality in Response to Irrigation With Saline Reclaimed Water and Deficit Strategies.

The 70% worldwide surface of olive orchards is irrigated. The evaluation of non-conventional water resources and water-saving techniques has gained importance during the last decades in arid and semiarid environments. This study evaluated the effects of irrigation with two water sources: low-cost water DEsalination and SEnsoR Technology (DESERT) desalinated water (DW) ECw ∼1 dS m−1) and reclaimed water (RW) (ECw ∼ 3 dS m−1) combined with two irrigation strategies: full irrigation (FI) (100% of ETc) and regulated deficit irrigation (RDI, 50% of ETc) on fruit yield, ripening indices, and oil yield and quality of olive trees cv Arbosana planted in Mediterranean conditions. Our results showed that RW without water restrictions increased the fruit yield by 35% due to a slight increase in the fruit weight and, mainly, to a greater fruit set than the control trees; although this did not result in a higher oil yield (g tree−1) since the oil content per fruit dry weight was reduced. The RDI strategy did not decrease the fruit yield despite the fact that olive weight tended to decrease, and it increased the oil yield by ∼14.5%. The combination of both stresses (RW and RDI) neither decreased the fruit yield; however, it significantly reduced oil yield (25% less in 2018) since oil content per fruit dry weight was strongly reduced (40%) compared to control trees. Both RDI treatments, regardless water source, determined acidity levels in olive paste lower than in FI treatments; however, it reduced oil extractability and fatty yield. The finding about oil quality indicated that olive exposure to RW, regardless of the water amount, decreased oil quality mainly due to the reduction of oleic acid and the increase of C18:2/C18:3 ratio and peroxides; on the contrary, both RW and RDI improved the total polyphenols. In all cases, the parameters met the legislation. In short, with appropriate management, RW and RDI have great potential to manage oil olive production; nevertheless, studies subjected to long-term use of these techniques should be experienced to ensure the sustainability of oil yields and quality.

Seed yield and oil quality of sunflower, safflower, and sesame under different levels of irrigation water availability

Water deficit stress is a common environmental factor affecting growth and yield of crops, but comparative studies on quantitative and qualitative characteristics among oilseed crops do not exist in the literature. A three-year field experiment was conducted in a calcareous soil of East Azerbaijan, Iran to determine the impact of water deficit stress on a number of quantitative and qualitative characteristics of sunflower (Helianthus annuus L.), safflower (Carthamus tinctorius L.), and sesame (Sesamum indicum L.). Four levels of irrigation, i.e., 40, 60, 80, and 100% of potential evapotranspiration (PET) were applied during the growing season. Low water availability significantly decreased seed yield in all oilseed crops, followed by a significant increase in malondialdehyde (MDA) and proline (Pro) content. Averaged over irrigation water availability levels, sunflower showed the greatest reduction in seed yield by 16.3%, followed by sesame (12.8%) and safflower (9.4%). The seed yield reduction in all crops was mainly due to a reduction in seed weight and a reduction in seed number in capitula or capsules. Averaged over irrigation water availability levels, sunflower showed the greatest reduction in oil yield by 22.5%, followed by sesame (13.3%) and safflower (10.2%). Mild lack of irrigation water availability (80% of PET) neither affected negatively nor improved oil percentage, particularly in safflower and sesame. Severe lack of irrigation water availability (40% of PET) significantly reduced oil percentage, particularly in sunflower. A significant reduction in oleic acid (OA), linoleic acid (LA), linolenic acid (LNA), and palmitic acid (PA) content due to low availability of irrigation water was observed in all crops. Apart from breeding efforts for improving crop resistance to drought, management practices should be considered to reduce drought-related issues in major oilseed crops.

Comparative analysis of seed yield and biochemical attributes in different sunflower genotypes under different levels of irrigation and salinity

SUNFLOWER (Helianthus annus L.) is an important oilseed crop in so many countries which suffer from seed and oil yield reduction by limited water or soil salinity. Since some responses to water and salt stress are common, other responses may vary according to the genotype and/or stress level. The role of the genetic diversity on the responses of sunflower yield, oil quality and the fatty acid composition to the different levels of irrigation and soil salinity in two field experiments were investigated. Three registered parental lines; HA 429, HA 430 and HA 20 and two hybrids; H (A9xRF6) and H (A9xRF8), in addition to one cultivar; Sakha 53 were used in this study. The results showed significant effects of genotype, level of stress and their interactions on most of the examined characteristics. Water stress caused a major reduction of protein content and oil yield than salinity stress. Different genotypes with similar oil contents had different oil yields under stress treatments. The hybrids H (A9xRF6) and H (A9xRF8) showed less reduction in oil content by both irrigation and salinity treatments, compared to the other genotypes and this candidate them for cultivation in stressed regions. The results also showed that some fatty acids, particularly stearic acid and oleic acid, were dependent on the genotype and the stress level in both experiments.

Effect of selenium foliar application on oil yield, fatty acid composition and glucosinolate content of rapeseed cultivars under late-season thermal stress

To determine the possible protective and enhancer role of selenium foliar application on oil yield, fatty acid composition and glucosinolate content of rapeseed cultivars under late-season thermal stress, a factorial split-plot experiment based on randomized complete block design with three replications was carried out in Karaj, Iran during the two growing seasons 2014–2015 and 2015–2016. Three sowing dates (Oct. 7 as normal planting date), (Oct. 17 as semi-late planting date), (Oct. 27 as late planting date) and two selenium foliar application (non-application as control and sodium selenate as foliar application) were factorially randomized to main plots, and rapeseed cultivars were allocated to sub-plots. Plant materials were six cultivars including three hybrids and three Iranian open pollinated varieties. Late-season thermal stress caused by late planting date reduced oil yield, oil content, oleic acid, linoleic acid, palmitic acid and increased linolenic acid, erucic acid and glucosinolate content of investigated cultivars. The results of this study demonstrated that the highest amount of oil yield, oil content, oleic acid, linoleic acid, palmitic acid and the lowest amount of erucic acid and glucosinolate content were observed in L72 cultivar in both control and selenium application treatments. This study provided new important findings about the supportive and enhancer role of selenium in the form of sodium selenate on quantity and quality of oil in rapeseed plant.

Evolution of gas and shale oil during oil shale kerogen pyrolysis based on structural characteristics

Kerogen thermal chemical conversion has a significant role on oil shale utilization and is affected by its chemical structural characteristics. In this work, three oil shale kerogen from Huadian Dachengzi (DCZ), Gonglangtou (GLT) and Gonghe (GH) are studied by TG-FTIR-MS and fixed bed pyrolysis system to analyze evolution characteristics of gas and shale oil. Typical gaseous products, CH4, H2, CO2 and CO, were analyzed by deconvolving their evolution curves. GCMS was employed to analyze the distribution of components in shale oils. Results show that studied four gases are related to several precursor structures and shale oil is mainly obtained from cracking of aliphatic structure in kerogen. Structural characteristics of kerogen affects its product distribution, resulting in higher yields of oil and hydrocarbon gases from kerogen DCZ and GH, while higher yields of char, aromatics and oxygen-containing products from kerogen GLT. Evolution behaviors of oil and gas products at different temperatures are related to cleavage of chemical bonds in kerogen. Labile CalO bonds crack below 350 ℃ causing removal of oxygen-containing functional groups and formation of CO2 and CO. Cleavage of CalCal/H bonds at 400–500 ℃ causes acute decomposition of kerogen and formation of abundant products. Incomplete decomposition of kerogen at low temperature results in low yields of oil and gas. At high temperature above 500 ℃, cleavage of CarCal/O/H bonds occurs and secondary reactions of oil products are intensified, causing reduction of oil yield and increases of gas yield.

Conventional and microwave-assisted pyrolysis of gumwood: A comparison study using thermodynamic evaluation and hydrogen production

The application of microwave energy in biomass pyrolysis has gained increasing interest due to its fast, volumetric, selective and efficient heating. However, the dominance may be levelled off if the energy and exergy efficiencies of overall system are taken into consideration. Hence, based on the lab-scale experimental data (at 600, 700 and 800 °C), energy and exergetic assessment of pyrolysis-derived gas, char and oil from gumwood under conventional and microwave heating were investigated in this work. The results showed that at each temperature, the corresponding energy and exergy rates of gas under microwave heating were found to be 23% and 26%, respectively, higher than those of conventional one. Meanwhile, the values for char were around 46%. This was mostly because microwave-derived pyrolysis product contained more gaseous and char products compared to the conventional process. In contrast, opposite trend was noticed for bio-oil due to the reduction of oil yield in pyrolysis product. It was demonstrated that the total energy and exergy value of individual pyrolysis products were significantly influenced by the energy and exergy content of individual component. For example, the increment rate of energy and exergy values of H2 and CH4 were sufficiently higher than the decrement rate of energy and exergy values of CO and CO2 with the increase of temperature; the total values were consequently increased at the elevated temperature. For the case of char and oil, the energy and exergy rate were decreased with temperature due to the reduction of individual product yield. Pyrolysis system efficiency (PSE), the overall performance indicator used in this study, of the microwave-assisted process was 13.5% higher than that of the conventional process. Moreover, the experimental results were further analysed with the conduct of a hydrogen plant simulation using Aspen Plus™ whose results confirmed that an improved performance of microwave heated system was achieved by producing 120 gH2/kg gumwood, 15% higher compared to that of conventional system.

Effect of simultaneous ultrasound/pulsed electric field pretreatments on the oil extraction from sunflower seeds

ABSTRACTIn this study, the individual and synergistic effects of ultrasound (US) and pulsed electric field (PEF) on the oil yield and content of functional food ingredients of sunflower oil were evaluated. The application of a PEF treatment (1.1 kV/cm) to the sunflower suspension significantly increased the extraction yield by 12.7%, with respect to hexane extraction. However, US/PEF treatment led to a reduction in oil yield as compared with US- and PEF-treated samples. Furthermore, the content of α-tocopherol was slightly higher for the oil after applying PEF-assisted extraction and a slight decrease in this content was observed for US- and US/PEF-assisted extraction.

Alleviation of water stress effects and improved oil yield in sunflower by application of soil and foliar amendments

We used small field plot experiments to evaluate alleviation of water stress damage with four soil or plant amendments. The experiment was conducted in two places during the 2012 growing season with sunflower (Helianthus annuus L.) as the crop. The water stress treatments were no stress (S0), moderate stress (S1) and severe stress (S2) as main factors. Two soil amendments were control (none), zeolite (4.5th−1) and a super absorbent hydrogel (100kgh−1). Two plant amendments were applied as foliar sprays, with three levels: control (none), calcium silicate (4mmoll−1), and the triazol hexaconazole (12mgl−1). The results showed the experimental treatments had significant effect on Biological yield, seed yield, oil percent, oil yield, 1000 seed weight, seed per plant, irrigation water productivity, economic water productivity rate in base of seed oil and economic water productivity rate in base of seed oil. 58% oil yield reduction was caused by water deficit stress in severe stress without amendments. The hydrogel and calcium silicate reduced this damage to 19%. Zeolite in all conditions increased the percent yield of oil. The application of both zeolite and hexaconazole resulted in the greatest improvement in irrigation water productivity. Severe water deficit stress reduced irrigation water productivity, economic water productivity rate, and economic water productivity rate in yield of seed oil by 31%, 32% and 24% in comparison with control respectively. Measured indicators showed yield and water use efficiency improvements when use in combination.

Interactive effects of drought stress and chitosan application on physiological characteristics and essential oil yield of Thymus daenensis Celak

Thymus daenensis, a perennial herb, is often grown in areas that experience drought conditions during its growing period. Application of chitosan may compensate for the negative impact of drought stress on the yield of oil and secondary metabolites in Thymus. The interactive effects of foliar application of chitosan and drought stress on dry matter, essential oil yield, and selected physiological characteristics including photosynthetic pigments, osmotic adjustment, and lipid peroxidation of Thymus were investigated in a two-year study from 2014 to 2015. Treatments consisted of 0, 200, and 400μLL−1 chitosan applied to plants grown under field capacity, mild drought stress (50% field capacity), and severe drought stress (25% field capacity). Dry matter yield decreased substantially as drought stress intensified. However, essential oil content increased under stress conditions, with the highest essential oil yield obtained from plants under mild drought stress. Foliar application of chitosan compensated to some extent for dry matter and oil yield reduction of plants grown under drought stress. The highest essential oil yield (1.52g plant−1) was obtained by application of 400μLL−1chitosan under the mild stress condition in 2015 when plants were mature. The compensatory effect of chitosan in reducing the negative impact of stress conditions on dry matter and oil yield was due mainly to stimulation of osmotic adjustment through proline accumulation and reduction of lipid peroxidase level, which increased the integrity of cell membranes of thyme leaves.

Characterization of oil shale pyrolysis by solid heat carrier in moving bed with internals

Oil shale pyrolysis by solid heat carrier in moving bed with internals (MBI) was investigated with the aim to identify the effect of oil shale properties (moisture content and particle size) and heat carrier types on the physicochemical properties and distributions of pyrolysis products. Pyrolysis of oil shale with high moisture content of 10wt% caused obvious increase in shale oil yield due to the protective effect of steam atmosphere by its reducing secondary reactions and also catalysis action of shale ash. The obtained highest shale oil yield was close to the yield of Fischer Assay. Pyrolyzing dried oil shale produced shale oil containing more light oils (gasoline and diesel) and allowed higher gas yield. Pyrolysis of large size (i.e. >10mm) oil shale reduced oil yield but increased light oil content due to the required long time for heat transfer and intra-particle volatile diffusion. Comparing with ceramic balls, shale ash as the heat carrier presented a favorably catalytic effect on cracking and upgrading of shale oil. With increasing pyrolysis temperature from 465 to 525°C, using shale ash greatly raised light oil content by 10.24% (relatively), considerably reduced the content of heteroatomic compounds, and promoted the conversion of aliphatics to aromatics. Shale ash carrier particles enabled better dust removal than ceramic balls did to attain oil product with a dust content below 0.2wt%. Generally, oil shale pyrolysis using shale ash heat carrier in MBI process has obvious effects of in-situ shale oil upgrading and in-bed dust removal to allow good pyrolysis performance.