Evaluation of fourBrassica germplasm collections for fatty acid composition

A total of 1116 accessions of cultivatedBrassica spp. from four collections were evaluated for fatty acid composition to identify variants which would be useful in plant improvement programs. The accessions included lines ofB. campestris L.,B. napus L.,B. oleracea L. andB. carinata Braun obtained from the USDA collections at Ames, IA, Pullman, WA, and Geneva, NY, as well as the Centre for Genetic Resources-the Netherlands (CGN) at Wageningen, Netherlands. Fatty acid composition of each accession was determined by using gas chromatography. The range, mean, standard deviation and frequency distributions were calculated for the seven primary fatty acids found in the accessions from each collection. Fatty acid profiles of the four species were very similar. Except for levels of erucic acid in the oilseed accessions ofB. campestris andB. napus, only limited economic variation in fatty acid composition was evident. These data suggest that in theseBrassica species the fatty acid profile has been tightly conserved. Estimated energy obtained by β-oxidation of a high erucic acid rapeseed (HEAR) oil was 13.8% higher than for a low erucic acid rapeseed (LEAR) oil. The higher energy levels of oils containing high levels of erucic acid may have played a significant role in survival and adaptation of these extremely small seedBrassica species. This may explain why such limited variation in fatty acid composition was found in these extensive and diverse collections.     

Allelochemical regulation of reproduction and seed germination of two BrazilianBaccharis species by phytotoxic trichothecenes

The potent phytotoxic trichothecene roridins and baccharinoids occur naturally in the Brazilian plants,Baccharis coridifolia andB. megapotamica. Biosynthesis of roridins inB. coridifolia appears to be linked to pollination, and the phytotoxins then accumulate in the seed. The roles of the phytotoxins in pollination, seed maturation, and germination of theBaccharis species were investigated. The high production of roridins occurred only in seeds resulting from intraspecific pollination, and the concentration of the toxins in the seeds generally increased with seed maturity. Removal of seed coats from trichothecene-producing BrazilianBaccharis species (B. coridifolia andB. megapotamica) and non-trichothecene-producing AmericanBaccharis species (B. halimifolia andB. glutinosa) resulted in improved seed germination ofB. halimifolia andB. glutinosa but complete inhibition of seed germination ofB. coridifolia andB. megapotamica. Addition of seed coat extracts of the BrazilianBaccharis species of dilute solutions (10^–6g/ml) of roridins or baccharinoids to the decoated seeds ofB. coridifolia andB. megapotamica resulted in germination, while seeds ofB. halimifolia andB. glutinosa were killed by the phytotoxins. Roridins interacted with gibberellic acid, a germination promoter, but not with abscisic acid, a germination inhibitor. The results from this study suggest that macrocyclic trichothecenes have a regulatory role(s) on reproduction and germination of BrazilianBaccharis species in their natural habitat.     

Antifouling agents against the benthic marine diatom,Navicula salinicola Homarine from the gorgoniansLeptogorgia virgulata andL. setacea and analogs

At concentrations found in the gorgonian corals,Leptogorgia virgulata (L.) andL. setacea (L.), homarine (N-methyl-2-carboxypyridine) and water-soluble extracts from the gorgonians that contained homarine inhibited the growth of the potential fouling diatom.Navicula salinicola Hust., by 50–60%. Homarine comprised 0.3 and 0.25% of the fresh weight ofL. virgulata andL. setacea, respectively, and the water-soluble extracts comprised 4.0 and 3.0% of the fresh weight of the gorgonians, respectively. Three compounds structurally related to homarine including, in order of most to least active, nicotinic acid, picolinic acid, and pyridine, also reduced growth ofN. salinicola. The activity of these compounds in the diatom assay suggests that the carboxyl group at the 2 position of the pyridine ring is important for activity and thatN-methylation is not important. We conclude that chemical defense against fouling is operative inLeptogorgia species. Evidence from the literature for combined chemical and mechanical defenses byLeptogorgia and other organisms against fouling is presented.     

Fatty acid compositions of the oils ofceltis sinensis var.japonica andzelkova serrata

Oils were extracted from the pits ofCeltis sinensis Pers. var.japonica Nakai and the fruits ofZelkova serrata Makino, of the family Ulmaceae. The oils were examined for their characteristics and fatty acid composition. The percentages of component acids ofCeltis andZelkova oils determined by gas liquid chromatography of their methyl esters were, respectively: propionic (−, 0.9), butyric (−, trace), caproic (−, 0.1), caprylic (−, 7.3), capric (−, 76.5), lauric (−, 3.3), myristic (0.1, 1.0), palmitic (6.8, 2.8), hexadecenoic (trace, −), stearic (3.5, 0.4), oleic (7.5, 3.9), linoleic (80.0, 3.3), linolenic (2.1, 0.5), and arachidic (trace, −) acids.     

Allelopathic research of subtropical vegetation in Taiwan. IV

The phytotoxicity of plant leachates was evaluated from four subtropical grasses:Brachiaria mutica, Digitaria decumbens, Imperata cylindrica var. Major, andPanicum repens. The aqueous leachate of each grass was used to water the growth of the four grasses in pots. The leachates exhibited variable inhibition of grass growth as compared to the tap water control. By the 41st day after treatment, the leachate ofD. decumbens significantly suppressed the growth of itself and retarded that ofB. mutica andP. repens. The growth ofB. mutica was inhibited by its own leachate, but that ofI. cylindrica was not affected by any of the grass leachates. In crop growth rate (CGR) analysis, the four grass leachates exhibited a similar inhibition pattern. In laboratory bioassays, the leachates showed a significant phytotoxic effect on the radicle growth of ryegrass and lettuce. Six phytotoxic phenolics were quantitatively compared by high-performance liquid chromatography, and the amount of compounds varied with species. The highest total amount of phytotoxic phenolics occurred inD. decumbens, followed, in decreasing order, byP. repens, B. mutica, andI. cylindrica. These findings show that the leachates of four grasses possess phytotoxic compounds that may play a significant role in grass dominance in the field.     

Caltha palustris L. Seed Oil. A source of four fatty acids withcis-5-unsaturation

The seed oil ofCaltha palustris L. yields two unusual polyunsaturated components, all-cis-5,11,14-eicosatrienoic acid (23%) and all-cis-5,11,14,17-eicosatetraenoic acid (1%). The C₁₈ monoene fraction (26%) is a mixture ofcis-5- andcis-9-octadecenoic acids (2∶1). The C₂₀ monoene fraction (12%) is a mixture ofcis-11- andcis-5-isomers (3∶1). No. Utiliz. Res. Dev. Div., ARS, USDA.     

Kairomones and their use for management of entomophagous insects: III. Stimulation ofTrichogramma achaeae,T. pretiosum,andMicroplitis croceipes with host-seeking stimuli at time of release to improve their efficiency

Frass from larvae of the corn earworm,Heliothis zea (Boddie) and scales fromH. zea moths (that are known to contain the host-seeking stimulus, tricosane) stimulate and orient host-seeking activity in femaleMicroplitis croceipes (Cresson), a larval parasite ofH. zea, andTrichogramma spp., egg parasites ofH. zea. When larval frass, moth scales, and tricosane were used as sign stimuli (releasers) forM. croceipes, T. pretiosum (Riley), andT. achaeae Nagaraji and Nagarkatti, respectively, at time of their release from laboratory containers, parasite performance improved, resulting in significantly increased rates of parasitization over that of unstimulated parasites. Stimulation ofM. croceipes with larval frass had an overriding effect on this parasite's innate tendency to disperse upon release, thereby increasing the numbers remaining and prolonging their retention in the target area. Supplying the appropriate host-seeking stimuli to these 3 hymenopterous parasites ofH. zea at time of their release to improve their efficiency greatly increases the probability of their effective utilization in pest management systems.     

Search for new industrial oils,IX.Cuphea,a versatile source of fatty acids

Seed oils from five species ofCuphea show three distinct patterns of fatty acid composition.C. hookeriana andC. painteri oils contain ca. 70% caprylic acid,C. ignea and C.llavea oils have over 80% capric acid, andC. carthagenensis oil contains 57% lauric and 18% capric acids. No. Utiliz. Res. and Dev. Div., ARS, USDA ARS, USDA     

Analysis ofcis- andtrans-fatty acid isomers in hydrogenated and refined vegetable oils by capillary gas-liquid chromatography

For quantitation ofcis- andtrans-fatty acid isomers, infrared (IR) spectroscopy, gas-liquid chromatography (GLC) on highly polar stationary phases or the combination (GLC-IR) may be used. IR offers the advantage of simplicity and speed, but the lower determination limit of 5% and the lack of detailed information limit its use. Detailed fatty acid information, required for, e.g., food-labeling purposes, can only be obtained with GLC methods. Most of the GLC methods are optimized for partially hydrogenated samples. AOCS Official Method Ce 1c-89 prescribes a single, highly polar stationary phase, SP2340, but underestimates the amount oftrans isomers due to 18∶1 positional isomer overlap. The combined GLC-IR method may circumvent this problem but at the cost of time, effort, and precision.Trans isomers in refined (deodorized or stripped) oils are different in type and levels from isomers in partially hydrogenated oils; theirtrans isomers are mono-trans trienoic and dienoic isomers, occurring at levels up to about 1–3%. GLC conditions for hydrogenated samples are often not suitable for refined oils because of overlap problems, but this time in the 18∶3 region. Through careful selection of stationary phase and temperature program optimization (Drylab^®GC), we have developed a single method that is suitable for hydrogenated, as well as refined, processed oils. The accuracy was checked withcis andtrans fatty acid fractions isolated by silverion exchange high-performance liquid chromatography. Thetrans values obtained with the optimized method are in good agreement with the results obtained for the isolated fractions. We propose that recommended methods describe GLC conditions in terms of separation criteria rather than recommending only a fixed combination of stationary phase and temperature program.     

Inhibition of seedling growth of crop species by recirculating root exudates ofBidens pilosa L.

The allelopathic effects of root exudates ofBidens pilosa L. on seedling growth ofLactuca sativa L.,Phaseolus vulgaris L.,Zea mays L., andSorghum bicolor (L.) Moench were studied using a root exudate recirculating system that allows continuous exposure of crop plants to allelopathic chemicals. This system maintains an undisturbed rhizosphere and eliminates competition and physical contact between the donor and acceptor plants. Comparison of responses to hydrophobic and hydrophilic root exudates is made possible by removal of hydrophobic compounds using XAD-4. Treatments consisted ofB. pilosa, B. pilosa with an Amberlite XAD-4 resin column attached to the donor pot to remove hydrophobic allelochemicals, and a donor pot without weeds.B. pilosa significantly inhibited seedling growth of all crop species tested. The crop species varied in response to the root exudates, withL. sativa being most sensitive. Larger and olderB. pilosa plants caused greater inhibition of seedling growth ofL. sativa andP. vulgaris than did smaller (younger)B. pilosa plants.B. pilosa with XAD-4 caused significantly less inhibition to all crop species, exceptZ. mays, thanB. pilosa without XAD-4, indicating that the hydrophobic exudates played an important role in the allelopathic growth inhibition. Variability in species response toB. pilosa with and without XAD-4 was probably due to differences in sensitivity to hydophobic and hydrophilic allelochemicals.Supported by a grant under USDA Agreement No. 83-CRSR-2-2293. Journal Series No. 2887 of the Hawaii Institute of Tropical Agriculture and Human Resources.     

Spodoptera exigua: Capture of feral males in traps baited with blends of pheromone components

Field tests were conducted with various blends of acetates and alcohols previously identified as components of the sex pheromone for the beet armyworm (BAW),Spodoptera exigua (Hübner). The compounds were formulated on rubber septa and placed in sticky traps positioned in fields populated withAmaranthus sp., a favored host of this species. Moth captures were highest in traps baited with septa containing a blend of 0.1 mg (Z,E)-9,12-tetradecadien-1-ol acetate (Z9,E12–14∶Ac) and 0.01 mg(Z)-9-tetradecen-1-ol (Z9–14∶OH). Additionally, we confirmed that all combinations of acetates tested alone captured significantly fewer males than blends containing a 10∶1 ratio ofZ9,E12–14∶Ac andZ9–14∶OH. A 10∶1 formulation ofZ9,E12–14∶Ac andZ9–14∶OH in hollow fibers was also attractive to feral BAW males.     

Cis-5-polyenoic acids inLarix leptolepis seed oil

cis-5,cis-9-Octadecadienoic acid (2.7%) andcis-5,cis-9,cis-12-octadecatrienoic acid (24.9%) are present in the seed oil ofLarix leptolepis. The double bond positions were identified by ozonolysis and by gas chromatography-mass spectrometry of methoxy derivatives. Small quantities of branched chain acids of various chain lengths were indicated by gas chromatography. The presence of C₁₇ and C₁₉ branched methyl esters was confirmed by gas chromatography-mass spectrometry.     

Study on neutral lipid composition of malagasy zebu fats: I. Quantitative analysis of fatty acids and sterols

The fatty acid and sterol compositions of different parts of Malagasy zebu(Bos indicus) were evaluated. Investigation by gas liquid chromatography using Carbowax 20 M revealed 35 fatty acids, mainly palmitic (24-27%), stearic (13-24%), and oleic (25-37%) acids. Odd-numbered, iso and anteiso fatty acids were also detected. Small differences in composition were observed between the hump and the kidney fats ofB. indicus. Comparison between industrial tallow ofB. indicus andB. taurus revealed slight differences in the stearic/ oleic acid ratio (0.83 and 0.46, respectively). An OV 17 column was used to separate 9 sterols, mainly cholesterol (89-98%).β-Sitosterol was also found at lower concentrations in all the samples.     

Ratio of in vivo incorporation of3H arachidonic acid and14C linoleic acid into liver lipids from normal and diabetic rats

Normal and streptozotocin diabetic rats were injected via the portal vein with a labeled solution containing³H arachidonic acid and¹⁴C linoleic acid (³H/¹⁴C ratio, 0.5) during a 1 min period. Livers were quickly frozen, pulverized, and the lipids extracted and fractioned by thin layer chromatography. The incorporation of³H and¹⁴C into liver lipids was measured and the percentage distribution of radioactivity into the different lipid fractions was determined. The incorporation of¹⁴C linoleic acid and³H arachidonic acid into liver lipids is apparently reduced in rats with severe diabetes. The higher³H/^14C ratio found in the 1,2 diglycerides from diabetic rats may be explained by the apparently smaller incorporation of¹⁴C linoleic acid or by an isotopic dilution attributable to the great availability of this acid in diabetic rats. On the other hand, the higher³H/¹⁴C ratio observed in triglycerides and phospholipids from diabetic rats, due to a relatively large incorporation of³H arachidonic acid into this fraction, may be explained by the affinity of the enzymes involved in their synthesis for some 1,2-diglyceride units. Insulin was unable to correct the changes observed in the diabetic rats.     

Analyses of fatty acid isomers in two commercially hydrogenated soybean oils

A conventional shortening and a hydrogenated winterized oil have been investigated to determine their composition of natural and isomeric fatty acids. Two solvent systems were applied in countercurrent distributions: the acetonitrile pentane-hexane system for separation of monoenoates from dienoates and the methanolic silver nitrate pentane-hexane system for separation of geometric isomers. Whilecis andtrans monoenoates were well resolved, the separation ofcis,cis fromcis,trans dienoates was complicated by the presence of positional isomers. The fractions isolated were oxidatively cleaved, and the esters of the resultant acids were quantitatively analyzed by gas-liquid chromatography. Although the amounts of saturated components of the two fat products were similar, the percentage oftrans isomers of the shortening was more than twice that of the winterized oil. The amount of oleic acid (cis-9-octadecenoic) was 19.6% for the shortening and 25.4% for the winterized oil. The shortening contained 13.3% linoleic acid (cis,cis-9,12-octadecadienoic), whereas the winterized oil contained 30% linoleic acid. Although our primary interest was in the estimation ofcis-9-octadecenoic andcis,cis-9,12-octadecadienoic acids, the completeness of cleavage data makes it possible to estimate all geometric and positional monoenoate and dienoate isomers in the two fat products. Presented at AOCS meeting in New Orleans, La., May, 1962. A laboratory of the No. Utiliz. Res. and Dev. Div., ARS, USDA.     

Identity and configuration of conjugated fatty acids in certain seed oils

Punicic acid was found in the seed oils ofCayaponia grandifolia, Trichosanthes cordata andT. cucumerina. α-Eleostearic acid was found inMomordica cochinchinensis, M. cochinchinesis varietymixta andM. cymbalaria. The identity of the conjugated triene acid ofAleurites trisperma, Garcia nutans andCyclandrophora laurina was confirmed as α-eleostearic acid (cis, trans, trans configuration). The configuration of kamlolenic acid was proved to becis-9,trans-11,trans-13. The oils ofAleurites remyi andLicania platypus did not contain any conjugated acid. Issued as N.R.C. No. 10589.     

Behavioral and electrophysiological responses of Aphids to host and nonhost plant volatiles

Alate and apterous virginoparae ofAphis fabae Scop, and alate virginoparae ofBrevicoryne brassicae (L.), walking in a linear track olfactometer, were attracted by odor from leaves of their host plants.A. fabae responded to odor from undamaged but not damaged bean leaves. Gynoparae (autumn migrants) ofA. fabae, however, did not respond to their host plant (spindle,Euonymus europaeus) odor. Odors of certain nonhost plants masked the attractiveness of the host plant leaves, but tansy (Tanacetum vulgare) and summer savory (Satureja hortensis) volatiles repelledB. brassicae andA. fabae, respectively. 3-Butenyl isothiocyanate attractedB. brassicae andLipaphis erysimi (Kalt.), the latter species being more sensitive in both behavioral and electrophysiological studies. Isothiocyanate receptors were found on the antennae ofA. fabae, which was repelled by these compounds, 4-pentenyl isothiocyanate being the most active.     

Characteristics and composition of six malvaceae seeds and the oils

The seeds ofSida veronicifolia Linn., syn.S. bumilis cav.,S. cordifolia Linn.,S. ovata Forsk.,S. mysorensis W & A., syn.S. urticaefolia W & A,S. rhombifolia var.retusa Masters andAbutilon crispum Medik. (Malvaceae) contained 15.5%, 11.5%, 12.1%, 13.2%, 20.2% and 12.5% oil, and 15.0%, 14.1%, 17.3%, 13.6%, 12.6% and 18.4% protein, respectively. Linoleic acid predominated (54.9–69.4%) as the fatty acid of all the oils, and malvalic (1.3–11.4%) and sterculic acids (0.4–1.1%) were significant.     

Reduced offspring production in bark beetleTomicus piniperda in pine bolts baited with ethanol and α-pinene,which attract antagonistic insects

Bolts of Scots pine,Pinus sylvestris L., attacked by the bark beetleTomicus piniperda (L.) were baited with ethanol and -pinene to attract antagonistic insects and thereby enhance their detrimental effects on the production of bark beetle progeny. Unbaited and caged bolts were included in the experiments as controls. Attraction of beetles to the bolts and subsequent emergence were estimated using traps. Six phloem-feeding species (potential competitors ofT. piniperda) and four predatory species were caught in significantly higher numbers at the baited bolts than at the unbaited ones. The number of offspring and the productivity ofT. piniperda were four to seven times higher in unbaited bolts than in baited bolts. Exclusion of other insects, by using cages, resulted in a nine-fold increase in the number ofT. piniperda offspring per square meter and productivity (offspring per egg gallery) compared with unbaited, exposed bolts.Hylurgops palliatus (Gyll.) (Scolytidae) andRhagium inquisitor (L.) (Cerambycidae) attacked both the baited and unbaited bolts, whereasAcanthocinus aedilis (L.) (Cerambycidae) andPytho depressus (L.) (Pythidae) reproduced almost exclusively in the baited ones. Large numbers of larvae ofThanasimus (Cleridae) andRhizophagus (Rhizophagidae) emerged from both the baited and unbaited bolts. Adults ofPlegaderus vulneratus (Panzer) andCylister linearis (Er.) (Histeridae) emerged almost exclusively from the baited bolts. The low progeny production ofT. piniperda in the baited bolts was attributed largely to the influence of adults ofRhizophagus andEpuraea (Nitidulidae), and larvae ofThanasimus andA. aedilis.     

Allelopathy ofSasa cernua

Sasa (Sasa cernua Makino) is a very serious weed pest. Its allelopathy was studied using lettuce, wheat, timothy, and green amaranth as testing species. Cultured in the rhizosphere soil ofSasa cernua, the seedlings were inhibited by 42–80% compared with the controls cultured in normal soil and vermiculite. The phenolic fraction extracted with 1 M NaOH from the rhizosphere soil ofS. cernua caused significant inhibitions on the seed germination and seedling growth of lettuce, timothy, green amaranth, and barnyard grass.p-Coumaric, ferulic, vanillic, andp-hydroxybenzoic acids andp-hydroxybenzaldehyde were identified as the main allelochemicals in sasa soil by HPLC and [¹H]NMR. Their contents in the rhizosphere soil were 5640, 1060, 860, 810 and 630 μg/100 g soil. The neutral fraction inhibited the seed germination and seedling growth of lettuce in the TLC direct bioassay. Volatile compounds released from sasa leaves also inhibited the growth of lettuce, wheat, timothy, and green amaranth grown under light, and the growth of etiolated seedlings of barley and wheat. These results confirm thatS. cernua produces typical allelopathy through its rhizosphere soil and air space.