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1.
The essential oil of Rosa damascena Mill. is one of the most valuable and important base material in the flavor and fragrance industry. The aim of this study was to determine the effects of harvest date, fermentation duration and Tween 20 treatment on the essential oil content and composition of the rose petals. The essential oil content and composition were significantly different in the petals harvested at various dates (May 24, June 1, 8, and 15, 2002). The highest oil content was found on May 24 harvest (0.040%), and then a gradual decrease was observed up to last harvest date (0.032%). The highest percentages of geraniol, nerol, and phenylethyl alcohol were obtained from the petals harvested on May 24. However, the highest percentages of citronellol and linalool were found from the petals harvested on June 8. The petals collected freshly were fermented for various duration (0, 12, 24, and 36 h) at 25 °C in sacks. The highest essential oil content was found in the non-fermented petals. As fermentation duration increased, essential oil content gradually decreased. The most significant changes during the fermentation were observed in citronellol and geraniol contents. Citronellol/geraniol (C/G) ratio increased from 0.57 to 10.31 throughout the fermentation. In the other experiment, Tween 20 was added into the distillation water at various concentrations (0, 1000, 2500, and 5000 ppm). Although Tween 20 generally raised the contents of essential oil, it did not significantly influence the oil composition. The highest oil content (0.045%) was obtained from the distillation treated with 2500 ppm of Tween 20. Oil content had high positive correlations with geraniol and linalool contents (r=0.55 and 0.53, respectively), but high negative correlation with citronellol content (r=−0.48).  相似文献   

2.
Oil analysis in seeds of Salicornia brachiata was carried out in the current study. Hexane extraction yielded maximum oil content from seeds (22.4%). High ester (538.32 mg/g) and saponification (547.52 mg/g) suggest a potential for industrial use of the oil.  相似文献   

3.
《Field Crops Research》2006,95(2-3):250-255
The East African highland banana (Musa spp. AAA) is an economically important food crop. The crop is affected by a number of diseases and pests. Genetic improvement of the crop is hindered by very low seed set and poor seed germination. The objective of this study was to compare seed set, seed quality and embryo rescue rates of hybrid seeds obtained from 20 East African highland banana cultivars crossed with a fertile diploid species, Musa acuminata spp. burmannicoides ‘Calcutta 4’, as a male parent. There was great variation in seed set, seed quality and in vitro embryo germination rates among the cultivars. Although 72% (range = 47–88%) of the seeds appeared normal externally characterized by black hard integuments, only 59% (range = 35–81%) contained embryos, of which 9% (range = 0–22%) germinated. This study demonstrated that hard-seededness alone does not signify the presence of an embryo and should not be regarded as a measure of seed fertility in East African highland bananas. Cultivars ‘Entukura’, ‘Enzirabahima’ and ‘Kabucuragye’ of the ‘Nfuuka’ clone set were superior in terms of seed set, presence of seeds with embryos and culturability of embryos. These cultivars are recommended as female parents for a crossing program in the improvement of East African highland bananas. The low embryo rescue rates suggest that hybrid seeds derived from East African highland banana possess factors that cause high embryo abortion. This may be ascribed to endosperm breakdown, which can release toxins.  相似文献   

4.
The compositions of essential oils of 19 accessions belonging to six different Achillea species, transferred from the natural habitats in 10 provinces of Iran to the field conditions, were assessed. The relationship between the leaf areas of selected accessions with their essential oil content was also investigated. Essential oil yield of dried plants obtained by hydro-distillation ranged from 0.1 to 2.7% in leaves. Results indicated a significant variation in oil composition among and within species. Total of 94 compounds were identified in 19 accessions belonging to the six species of A. millefolium, A. filipendulina, A. tenuifolia, A. santolina, A. biebersteinii and A. eriophora. The major constituents of the leaves in the tested genotypes were determined as germacrene-D, bicyclogermacrene, camphor, borneol, 1,8-cineole, spathulenol and bornyl acetate. According to the major compounds, four chemotypes were defined as: (I) spathulenol (1.64–34.31%) + camphor (0.2–15.61%) (7 accessions); (II1) germacrene-D (18.78–23.93%) + borneol (7.93–8.26%) + bornyl acetate (11.56–14.66%) (5 accessions); (II2) germacrene-D (13.28–36.28%) + bicyclogermacrene (5.93–8.4%) + 1,8-cineole (15.26–19.41%) + camphor (14.95–23.32%) (2 accessions); (III) borneol + camphor (52.04–63.27) (2 accessions); (IV) germacrene-D (45.86–69.64%) (3 accessions). The relationships of chemotypes with soil type and climatic conditions of collected regions were assessed, as probable reasons of high variations in essential oil components, and discussed.  相似文献   

5.
Studies were conducted on the properties of seeds and oil extracted from Maclura pomifera seeds. The following values (on a dry-weight basis) were obtained for M. pomifera seed, respectively: moisture 5.88%, ash 6.72%, oil 32.75% and the high protein content 33.89%. The carbohydrate content (20.76%) can be regarded as a source of energy for animals if included in their diets. The major nutrients (mg/100 g oil) were: potassium (421.65), calcium (218.56) and magnesium (185.00). The physicochemical properties of the oil include: the saponification number 174.57; the iodine value 141.43; the p-anisidine value 1.86; the peroxide value 2.33 meq O2/kg; the acid value 0.66; the carotenoid content 0.59 mg/100 g oil; the chlorophyll content 0.02 (mg/100 g oil) and the refractive index 1.45. Polymorphic changes were observed in thermal properties of M. pomifera seed oil. This showed absorbency in the UV-B and UV-C ranges with a potential for use as a broad spectrum UV protectant. The main fatty acids of the crude oil were linoleic (76.19%), oleic (13.87%), stearic (6.76%) and palmitic acid (2.40%). The polyunsaturated triacylglycerols (TAGs) LLL, PLL, POL + SLL, OLL, OOL (L: linoleic acid, O: oleic, P: palmitic acid and S: stearic acid) acids were the major TAGs found in M. pomifera seed oil. A relatively high level of sterols making up 852.93 mg/100 g seed oil was present. The sterol marker, β-sitosterol, accounted for 81% of the total sterol content in the seed oil and is followed by campesterol (7.4%), stigmasterol (4.2%), lupeol (4.1%) and Δ5-avenesterol (3.2%). The seed oil was rich in tocopherols with the following composition (mg/100 g): α-tocopherol 18.92; γ-tocopherol 10.80; β-tocopherol 6.02 and δ-tocopherol 6.29. The results showed that M. pomifera seed oil could be used in cosmetic, pharmaceutical and food products.  相似文献   

6.
《Field Crops Research》2005,93(1):64-73
Leaf area growth and nitrogen concentration per unit leaf area, Na (g m−2 N) are two options plants can use to adapt to nitrogen limitation. Previous work indicated that potato (Solanum tuberosum L.) adapts the size of leaves to maintain Na and photosynthetic capacity per unit leaf area. This paper reports on the effect of N limitation on leaf area production and photosynthetic capacity in maize, a C4 cereal. Maize was grown in two experiments in pots in glasshouses with three (0.84–6.0 g N pot−1) and five rates (0.5–6.0 g pot−1) of N. Leaf tip and ligule appearance were monitored and final individual leaf area was determined. Changes with leaf age in leaf area, leaf N content and light-saturated photosynthetic capacity, Pmax, were measured on two leaves per plant in each experiment. The final area of the largest leaf and total plant leaf area differed by 16 and 29% from the lowest to highest N supply, but leaf appearance rate and the duration of leaf expansion were unaffected. The N concentration of expanding leaves (Na or %N in dry matter) differed by at least a factor 2 from the lowest to highest N supply. A hyperbolic function described the relation between Pmax and Na. The results confirm the ‘maize strategy’: leaf N content, photosynthetic capacity, and ultimately radiation use efficiency is more sensitive to nitrogen limitation than are leaf area expansion and light interception. The generality of the findings is discussed and it is suggested that at canopy level species showing the ‘potato strategy’ can be recognized from little effect of nitrogen supply on radiation use efficiency, while the reverse is true for species showing the ‘maize strategy’ for adaptation to N limitation.  相似文献   

7.
《Field Crops Research》2006,96(1):142-150
The distribution, population density and incidence of plant parasitic nematodes and associated damage to yam (Dioscorea spp.) tubers obtained from market stalls in the West African countries of Benin, Burkina Faso, Côte d’Ivoire, Ghana, Mali, Nigeria and Togo was determined during the tuber storage periods in 2002 and 2003. A total of 527 yam tuber samples, exhibiting typical nematode (Scutellonema bradys) damage symptoms, were collected and assessed for S. bradys densities. In addition 25,318 tubers on sale in markets were assessed for visual symptoms (except in Nigeria) of nematode damage (S. bradys and Meloidogyne spp.). S. bradys was present in all countries assessed, with greatest (P ≤ 0.05) mean population densities occurring in tubers in Benin (397 g−1), followed by Nigeria (248 g−1) and lowest in Togo (28 g−1). When analysed by agroecological zone, the greatest (P ≤ 0.05) mean S. bradys density was observed in the mid altitude savannah (890 g−1), followed by the southern guinea savannah (488 g−1). S. bradys occurred in lower (P ≤ 0.05) densities on Dioscorea alata (57 g−1) than other yam species, while Dioscorea rotundata was the most abundant yam species encountered. There was considerable variation in S. bradys density between cultivars within country and in some cases between countries. From some cultivars no S. bradys were recovered, even though they presented symptoms of damage. Tubers from Ghana had the greatest (P ≤ 0.05) proportion of tubers visually affected by S. bradys (7.53%), when analysed across yam species and Mali the least (0.28%), while the highest proportion of galled tubers (due to Meloidogyne spp.) was observed in Mali (14.4%) on D. rotundata (19.6%). S. bradys infection, based on visible symptoms, was more evident on D. rotundata (3.8%) than D. alata (0.6%), although 5.18% of yams in the group comprising the unidentified yam species had the greatest mean proportion of visually affected tubers. On market stalls, D. alata (4.73%) and D. rotundata (3.35%) were most affected by visible galling due to Meloidogyne spp.  相似文献   

8.
Lesquerella fendleri (Gray) Wats. is a potential new oilseed crop for the arid southwestern United States. Lesquerella seed oil with similar properties as castor oil is being considered as a domestic replacement for the imported castor oil. Development of new crops with low irrigation needs is of high priority. Because the most critical stage of sensitivity to moisture deficits has not been determined in Lesquerella species, the objectives of this study were: (i) to identify the most critical stage or stages for moisture deficit and, (ii) to determine the effect of moisture deficit on yield, yield components, oil and fatty acid composition. Two-year field studies were conducted at the New Mexico State University, Leyendecker Plant Science Research Center. The experimental design was a randomized complete block. The treatments consisted of (a) T1: Continuous favorable soil moisture [irrigated at 50% soil water depletion (SWD)]. (b) T2: Moisture stress (75% SWD) from establishment to initial flowering with no stress from flowering to final harvest (50% SWD). (c) T3: No stress imposed from establishment to initial flowering (50% SWD) followed by stress to final harvest (75% SWD). (d) T4: Moisture stress (75% SWD) from establishment to final harvest. The amount of water applied ranged from 810 to 729 mm for the first year, and 810 to 625 mm for the second year. Seed weight per plant and number of pods per plant were generally higher when water availability was maintained at or above 50% SWD throughout the growing season. Neither seed number per pod nor seed size was influenced by irrigation treatments. Lesquerella was more sensitive to water availability during flowering and seed development as a greater loss in seed yield occurred when irrigation was delayed to 75% SWD during that stage of development. Seed yield and dry matter production from the 2 year field studies were closely related to the seasonal cumulative evapotranspiration. For each millimeter of evapotranspiration, seed yield increased from 1.8 kg ha−1 mm in 1994–1995 to 1.3 kg ha−1 mm for 1995–1996. The dry matter production increased 13.4 kg ha−1 for each mm increase in seasonal evapotranspiration during 1994–1995. This relationship was a second order polynomial with an R2 of 0.86 during 1995–1996. The WUEgr and WUEdm were highest under the most favorable water availability conditions for growth and seed development. Delaying irrigation to 75% SWD throughout the crop growth period resulted in the lowest oil content. Lesquerolic acid content was not affected by irrigation during both the growing seasons.  相似文献   

9.
The feasibility of producing biodiesel from Idesia polycarpa var. vestita fruit oil was studied. A methyl ester biodiesel was prepared from refined I. polycarpa fruit oil using methanol and potassium hydroxide (KOH) in an alkali-catalyzed transesterification process. The experimental variables investigated in this study were catalyst concentration (0.5–2.0 wt.% of oil), methanol/oil molar ratio (4.5:1 to 6.5:1), temperature (20–60 °C) and reaction time (20–60 min). A maximum yield of over 99% of methyl esters in I. polycarpa fruit oil biodiesel was achieved using a 6:1 molar ratio of methanol to oil, 1.0% KOH (% oil) and reaction time for 40 min at 30 °C. The properties of I. polycarpa fruit oil methyl esters produced under optimum conditions were also analyzed for specifications for biodiesel as fuel in diesel engines according to China Biofuel Systems Standards. The fuel properties of the I. polycarpa fruit oil biodiesel obtained are similar to the No. 0 light diesel fuel and most of the parameters comply with the limits established by specifications for biodiesel.  相似文献   

10.
Transmission electron microscopy of sections of oat (Avena sativa L.) grain suggested that the highest concentrations oil bodies were in the aleurone and germ rather than the starchy endosperm. Oil bodies recovered from homogenized tissues by centrifugation and washed in (9 M) urea were significantly (P<0.05) enriched in lipid (93.3±1.4% dry wt) and low in protein (1.4±0.2%) compared with unwashed (40.2±1.9% lipid; 23.0±1.8% protein), water-washed (78.6±1.2% lipid; 7.8±0.5% protein), and salt-washed (1 M NaCl) oil bodies (89.9±0.4% lipid; 5.1±0.4% protein). Washing significantly reduced (P<0.05) the total phenolic content of the oil bodies but significantly increased concentrations of E-vitamers, on a dry weight basis, suggesting an intrinsic association between the E-vitamers and oat oil bodies. The profile of E-vitamers in the oil bodies reflected that in oat grain with α-tocotrienol accounting for ca. 66% of the total E-vitamers. These E-vitamers may provide oxidative stability to the membrane and/or oil of oat oil bodies  相似文献   

11.
《Field Crops Research》2005,91(2-3):217-229
Soybean [Glycine max (L.) Merr.] seed is a major source of protein for animal feed and oil for human consumption. Selection within elite soybean cultivars for the improvement of agronomic and seed traits is assumed to be ineffective due to the belief that cultivars are highly homogeneous. Previously reported data suggest that latent variation among the single plant selections within a cultivar exists and that mechanisms that generate de novo variation may also be present. The main objective of this study was to perform divergent single-plant selection at ultra-low plant density and investigate the presence of genetic variation for seed protein and oil within three elite soybean cultivars. A secondary objective was to investigate the variation for fatty acid composition. In 1995, single plants from the three cultivars were grown in a honeycomb design using a plant-to-plant spacing of 0.9 m. A total of 333 plants from ‘Benning’, 392 plants from ‘Haskell’, and 371 plants from ‘Cook’ were evaluated. Divergent single-plant selection for protein and oil content was performed to select a total of 20 plants for high or low protein and 20 plants for high or low oil from each cultivar. The selected plants were further evaluated in replicated row-plot experiments for 3 years. Our results indicate that single-plant selection at low plant density was successful in discovering significant variation for seed protein and oil within each of the three soybean cultivars. For protein content, the magnitude of intra-cultivar variation between the highest- and lowest-protein lines averaged 19 g kg−1 across the three cultivars and ranged from 13 to 24 g kg−1. For oil composition, the magnitude of variation between the most divergent lines averaged 12 g kg−1 across the three cultivars and ranged from 9 to 14 g kg−1. Significant variation among the selected progeny lines was also discovered for specific fatty acid composition. The magnitude of intra-cultivar variation averaged from 6 to 29 g kg−1 across the five fatty acids of soybean. The genetic variation discovered within the soybean cultivars is most likely due to latent variation and/or newly created variation. Our data provide evidence that single-plant selection at ultra-low plant density within elite cultivars can be effective in improving the seed composition of a soybean cultivar.  相似文献   

12.
Thymus zygis ssp. gracilis shrubs were cultivated as an experimental crop under different watering level, in order to achieve 81, 63, 44 and 30% of the local potential evapotranspiration (ETo). After 4 years of cultivation, thyme leaves were analyzed on the basis of their essential oil (yield and quality), total phenolic content, free radical-scavenging activity and polyphenolic profile.Essential oil yield values ranged between (2.3 ± 0.7) and (3.6 ± 0.7)% for 81 and 30% ETo equivalent, respectively. The comparison of essential oil production at the 2nd and 4th years of cultivation showed that using watering levels higher than 30% ETo equivalents reduced significantly (P < 0.05) the essential oil yielded by these shrubs with time.Analysis of total phenolic content, polyphenolic profile, and radical scavenging activity were performed using post-distillation dry leaves. Total phenolic content values ranged from (122.2 ± 19.3) to (108.5 ± 19.2) mg of gallic acid equivalents (GAEs)/g of dry plant for the highest and lowest watering level treatment, respectively. Regarding the polyphenolic profile, rosmarinic acid, followed by apigenin, ferulic, carnosic and caffeic acids, was the phenolic component quantified at the highest concentrations. Radical-scavenging activities (IC50) concentrations varied from (3.7 ± 1.6) mg/mL for 81% ETo to (7.4 ± 2.3) mg/mL 30% ETo.In spite of the intra-specific variability detected, the individual analysis of shrubs has allowed the selection of plants which are characterised by having adequate levels of essential oil and polyphenolic extract (yield and quality), almost all of them being cultivated under a 60% ETo watering level. These selected shrubs will allow us to make further vegetative propagations in order to obtain homogeneous field crops with plants of contrasted quality cultivated under a 60% ETo watering level.  相似文献   

13.
《Field Crops Research》2001,69(1):41-46
The effects of two mixtures of four plant growth regulators (choline chloride, gibberellin (GA3), benzyladenine (6-BA) and NaHSO3) at 20:9:5:800 mg kg−1 (H1) and 20:42:43:2350 mg kg−1 (H3) (active ingredients), respectively, were investigated on yield and fiber quality in ramie (Boehmeria nivea (L.) Gaud.). The mixtures were sprayed over the canopy at two growth stages (10 and 20 days after the previous cut) of field-grown ramie. The treatments increased raw fiber yield by 13–18%, and improved fiber fineness by 57–349 m g−1, increased number of leaves per plant, and also improved all yield components. Treatment H1 resulted in a denser distribution, smaller diameters and greater quantity of fiber cells in stem cross-section. Physiological responses included improving leaf water status, increasing net photosynthetic rate, and decreasing electrolyte exosmosis rate.  相似文献   

14.
《Field Crops Research》2002,78(1):51-64
The effects of differential irrigation and fertiliser treatments on the water use of potatoes (Solanum tuberosum L. cv. Desirée) were studied over 2 years in the hot dry climate of northeast Portugal. Total actual evapotranspiration (ETc) ranged from 150 to 320 mm in 1988, and from 190 to 550 mm in 1989 depending mainly on irrigation treatment, potential evaporation rates (ETp) and duration of the growing season. By comparison, the effects of nitrogen fertiliser on total water use were relatively small. Although nitrogen increased transpiration (larger leaf canopy), it reduced evaporation from the soil surface, in frequently irrigated plots, by similar amounts. As a result, in well-irrigated crops, the ETc/ETp ratio averaged 0.85 over the season, regardless of nitrogen level. Evaporation from the soil surface represented 15–25% of total water use by well-fertilised plants, but as much as 30–50% from the sparse stands of unfertilised crops. The proportion of water extracted from each depth increment of the silt-loam soil declined logarithmically, from the surface to 1.1 m depth, the maximum measured, for irrigated crops, and linearly when rain-fed. The ETc/ETp ratio fell below unity when 25–30% of the available water in the top metre had been depleted, equivalent to soil water deficits (SWDs) of 45–50 mm. By comparison, ETc declined to zero when 75–90% of the available water had been extracted, corresponding to actual deficits of 135–150 mm. Peak ETc rates reached 12–13 mm per day on days immediately following irrigation, nearly twice ETp (possibly due to the influence of advection) but then declined logarithmically with time to about 3 mm per day within 5 days. Using the same data, a companion paper reports the influence of climatic conditions on the yield responses to water of potato crops grown in the region.  相似文献   

15.
Ferulic acid is a hydroxy cinnamic acid derivative found ubiquitously throughout the plant kingdom, is especially abundant in rice and corn bran, and possesses excellent ultraviolet (UV) and antioxidant properties. Ferulic acid was enzymatically incorporated into soybean oil to form feruloylated monoacyl- and diacylglycerols (FAG). The FAG possess the UV-absorbing and antioxidant properties of ferulic acid but are water insoluble and extremely lipophilic. These characteristics make FAG attractive in the cosmeceutical industry as an all-natural replacement for petroleum-based sunscreen active ingredients and antioxidants. The FAG were synthesized from the transesterification of soybean oil with ethyl ferulate catalyzed by the commercial lipase, Novozym 435 (Candida antartica lipase B). The FAG were encapsulated as microdroplets within a starch matrix via steam jet cooking (140 °C and 225 kPa). Up to 50% (w/w) of the feruloylated lipids was encapsulated into the starch matrix with the microdroplets ranging in size from 1 to 10 μm. Transmittance and irradiance measurements of UV radiation (300–400 nm) through thin films of neat FAG (not manipulated after FAG synthesis) and starch-encapsulated FAG showed that the FAG retained its ultraviolet-absorbing efficacy after steam jet cooking. Furthermore, starch-encapsulation of the FAG was found to enhance the ultraviolet absorbance of the feruloylated lipids. When encapsulated at 50% (w/w) in the starch matrix, one-half of the coverage (mg/cm2) of FAG was required to block the same amount or more UV radiation as neat FAG. The starch-encapsulated FAG was formulated as an aqueous dispersion without the need for emulsifiers or surfactants. The dispersions were drum dried to a powder and shown to be easily reconstituted into water dispersions without the loss of ultraviolet-absorbing efficacy.  相似文献   

16.
《Field Crops Research》2006,95(2-3):171-181
The importance of root systems in acquiring water has long been recognized as crucial to cope with drought conditions. This investigation was conducted to: (i) evaluate the variability on root length density (RLD) of chickpea in the vegetative growth stage; (ii) estimate the effect of RLD on seed yield under terminal drought conditions; and (iii) set up a procedure to facilitate the screening of chickpea genotypes with large RLD. Twelve diverse chickpea genotypes were grown in tall PVC cylinders with two different soil water treatments in 2000 and 2001, and in field under water deficit conditions during 2000/2001 and 2001/2002. In field trials, the mean RLD at 35 days after sowing showed a significant positive correlation with seed yield in both years. Similarly, the RLD in the 15–30 cm soil depth had significant positive effects to the seed yield in both years. The importance of the root trait was particularly relevant in 2001/2002, a more severe drought year, when the RLD in deeper soil layer, 30–60 cm depth, showed a significant positive relationship with seed yield. Also, the RLD at deeper soil layer, 30–60 cm depth, was higher in 2001/2002 than in 2000/2001, in particular in tolerant genotypes. The PVC cylinder trials were set up to facilitate the screening of chickpea genotypes with large RLD. RLD of plants grown in cylinders with 70% field capacity was correlated with RLD in the field trials (r = 0.731; p = 0.01). This work highlights the importance of roots in coping with terminal drought in chickpea. The cylinder system offers a much easier procedure to screen chickpea genotypes with large RLD.  相似文献   

17.
Steam-distilled dill (Anethum graveolens L.) oil yield and composition varies with the relative amount of vegetative and reproductive tissue and the maturity of the plant material distilled. The characteristics of the dill plant at harvest may be manipulated through production practices. A study was conducted in western Montana to determine the effects of crop maturity and plant density on dill plant growth and on oil production and quality. The crop was harvested at intervals from early fruit formation through fruit pigmentation. Oil yield declined with fruit maturity over the sampling period, particularly after the completion of fruit ripening and “seed” shatter. The carvone content of the oil increased and α-phellandrene decreased as the plant progressed from flowering to fruit ripeness. The highest oil yields with maximum carvone levels were obtained when most of the fruits on primary umbels were pigmented but had not become dry and fully mature. The balance between carvone and phellandrene in the oil was a function of the proportion of mature umbel tissue to vegetative and immature umbel tissue. Seeding rates of 2.2–17.9 kg ha−1 resulted in average plant densities of 100–474 plants m−2. Total biomass production and oil yield were generally unaffected by plant density, but plant population influenced plant architecture and oil composition. Plants grown at low density had a more extensive development of umbellate fruiting structures and a lower proportion of leaf and stem tissue than did plants at high density. Carvone was higher in oil from widely spaced plants, while phellandrene, α-pinene, and dill ether (3,9-epoxy-1-p-menthene) were lower. Harvest date and plant density affected oil composition in a complementary manner. An early harvest or high plant density is preferable if herbaceous oil characteristics are desired, while a late harvest or low plant density is suitable when growing dill for seed or for a high-carvone oil.  相似文献   

18.
Moisture-dependent physical properties of niger (Guizotia abyssinica Cass.) seed were studied at 5.60, 12.99, 19.77, 27.08 and 31.65% moisture content (wet basis). The length, width, thickness and geometric mean diameter increased significantly (p < 0.05) from 3.86 to 4.06 mm, 0.96 to 1.02 mm, 0.86 to 0.96 mm and 1.47 to 1.59 mm, respectively with increase in moisture content from 5.60 to 31.65% whereas the increase in sphericity from 38.10 to 39.01% was not significant. Similarly, thousand seed mass, porosity and angle of repose increased (p < 0.05) linearly from 2.50 to 3.69 g, 41.76 to 47.65% and 29.86° to 39.12°, respectively with increase in moisture content under the experimental condition. The bulk density decreased significantly (p < 0.05) from 635.23 to 561.06 kg m?3 with increase in the moisture content range considered in the study, whereas the true density showed a slight increase from 1090.71 to 1098.42 kg m?3 with increase in moisture content from 5.60 to 27.08% followed by a drop from 1098.42 to 1071.75 kg m?3 as moisture content increased from 27.08 to 31.65%. Coefficient of static friction increased (p < 0.05) logarithmically from 0.34 to 0.51, 0.38 to 0.56 and 0.13 to 0.53 on mild steel, plywood and glass surfaces, respectively with increase in moisture content from 5.60 to 31.65%.  相似文献   

19.
To evaluate the production potential of fiber nettle crops in Tuscany (Italy), a German clone of fiber nettle was cultivated during 2006–2007.Although a longer experimentation is essential, the two first years of trials showed that the German clone used also seems to give good results in term of growth and fiber yield in an environment like central Italy, with higher temperatures and generally lower rainfall. Indeed the stalk mean dry matter obtained was about 15.4 Mg ha?1 with a mean fiber content of about 11% of stalk dry matter, and the resulting fiber yield was 1696 kg ha?1, comparable to or higher than those reported in the literature.The differences in chemical, physical and mechanical characteristics of fibers extracted from different portions of stalks seemed to indicate an intrinsic heterogeneity of the fibers along the stem. Fiber mean diameter values ranged from 47 to 19 μm and fiber length from 43 to 58 mm moving from stalk bottom to top. Tensile strength of the bottom part of the stalk was much lower than that of the other parts, with mean values of about 24 and 60 cN tex?1, respectively. More constant mean values along the stalk were found for the elongation parameter (2.3–2.6%). Lignin content decreased moving toward the stalk top from about 4.4% to 3.5%.These physical–mechanical characteristics confirmed the potential of the fibers of nettle cultivated in Tuscany to be used for textile purposes. Indeed they were similar to hemp fibers in diameter, lignin content and elongation, and similar to flax or cotton in tensile strength.  相似文献   

20.
The essential oils of aerial parts of three Artemisia species (A. absinthium, A. santonicum and A. spicigera) were isolated by hydrodistillation method and tested for their toxicity against to granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae). All of the essential oils tested were found to be toxic to adults of S. granarius. The oils showed about 80–90% mortality of granary weevil, S. granarius at a dose of 9 μl/l air after 48 h of exposure. The constituents of these oils isolated from Artemisia spp. were also analyzed by GC–MS method. Camphor, 1,8-cineole, chamazulene, nuciferol propionate, nuciferol butanoate, caryophyllene oxide, terpinen-4-ol, borneol and α-terpineol were the predominant components of the oils. Some pure compounds (camphor, 1,8-cineole, terpinen-4-ol, borneol, bornyl acetate and α-terpineol) identified as major component in the oils, at 0.5, 0.75 and 1 μl/l air doses were also tested for their toxicity against S. granarius. While all pure compounds were found to be toxic against S. granarius, 1,8-cineole and terpinen-4-ol were more toxic among the tested pure compounds. 1,8-Cineole and terpinen-4-ol showed 100% mortality at all doses after 12 h of exposure. It can be concluded that essential oils of three Artemisia species and their major components, 1,8-cineole and terpinen-4-ol are potential control agents against S. granarius.  相似文献   

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