Oil Tubes Research Articles

Benefits of trenching behavior in the context of an inducible defense

Many species of insects sabotage the pressurized defense vessels of their host plants prior to feeding. This behavior, however, does not render leaves indefinitely suitable, as some species employing this behavior eventually abandon uneaten portions of sabotaged leaves. In this study, we examined whether and to what degree wild parsnip, Pastinaca sativa, is capable of restoring its pressurized defenses and whether cabbage loopers, Trichoplusa ni, which normally trench parsnip leaflets, benefit from their trenching behavior. The pressurized oil tubes of parsnip leaves are rich in toxic terpenoids and furanocoumarins. A disruption of the integrity of the tubes (via razor blade nicks) in leaflets revealed that that some of their contents were expelled at the break and that some movement of oil from outside the leaflet (i.e., the midvein) occurred, bolstering furanocoumarin levels in the leaflet within minutes. Pressure and chemical content in a leaflet’s oil tubes were also shown to be restored within 24 hours of depressurization. This recovery ability allowed parsnip leaflets to respond to daily depressurizations by mechanical damage for up to at least 5 assaults, cumulatively causing an approximate ten-fold increase in furanocoumarins. Cabbage loopers fed parsnip leaflets that were artificially trenched accumulated twice as much body mass as larvae fed leaflets augmented with furanocoumarins equivalent to the quantity that would be avoided through trenching, indicating that trenching does benefit the herbivore. Although parsnip recovers from trenching rapidly, it does not do so within the time that cabbage loopers consume trenched leaflets

Copolymer-Induced Stabilizing Effect of Highly Swollen Hexagonal Mesophases

We show that small amounts of copolymer that decorate an oil/water interface can greatly enhance the stability of swollen surfactant hexagonal phases, comprising oil tubes regularly arranged in a water matrix. Both the radius of the tubes and the thickness of the aqueous channel between the tubes can be controlled independently over large ranges. Such soft composite materials offer a potential interest for the synthesis of mesoporous materials.

Benefits of trenching behavior in the context of an inducible defense

Many species of insects sabotage the pressurized defense vessels of their host plants prior to feeding. This behavior, however, does not render leaves indefinitely suitable, as some species employing this behavior eventually abandon uneaten portions of sabotaged leaves. In this study, we examined whether and to what degree wild parsnip, Pastinaca sativa, is capable of restoring its pressurized defenses and whether cabbage loopers, Trichoplusa ni, which normally trench parsnip leaflets, benefit from their trenching behavior. The pressurized oil tubes of parsnip leaves are rich in toxic terpenoids and furanocoumarins. A disruption of the integrity of the tubes (via razor blade nicks) in leaflets revealed that that some of their contents were expelled at the break and that some movement of oil from outside the leaflet (i.e., the midvein) occurred, bolstering furanocoumarin levels in the leaflet within minutes. Pressure and chemical content in a leaflet’s oil tubes were also shown to be restored within 24 hours of depressurization. This recovery ability allowed parsnip leaflets to respond to daily depressurizations by mechanical damage for up to at least 5 assaults, cumulatively causing an approximate ten-fold increase in furanocoumarins. Cabbage loopers fed parsnip leaflets that were artificially trenched accumulated twice as much body mass as larvae fed leaflets augmented with furanocoumarins equivalent to the quantity that would be avoided through trenching, indicating that trenching does benefit the herbivore. Although parsnip recovers from trenching rapidly, it does not do so within the time that cabbage loopers consume trenched leaflets

Autotoxic effects of essential oils on photosynthesis in parsley, parsnip, and rough lemon

Many plant species contain essential oils with allelochemical properties, yet the extent to which these same chemicals can be autotoxic is unclear. In this study, we tested the toxicity of several essential oil components to three species that produce them—Pastinaca sativa and Petroselinum crispum (Apiaceae), and Citrus jambhiri (Rutaceae). The effects of exogenous application of small amounts of essential oil components to the surface of foliage, followed by a pinprick to allow entry into the leaf, were monitored by chlorophyll fluorescence imaging. Rapid and spatially extensive declines in photosynthetic capacity were detected within 200 s. The most toxic constituents were monoterpenes. Two sesquiterpenes, caryophyllene and farnesene, and the phenylpropanoid myristicin, by comparison, were not toxic. Autotoxicity of endogenous essential oil was investigated by slicing through containment structures (glands or tubes); significant toxicity, manifested by reduced photosynthetic activity, was observed in all three species but was most pronounced in P. sativa and P. crispum, both of which possess oil tubes.

Application of grey relational analysis for corrosion failure of oil tubes

Grey relational method was a data process method used to sort out the correlation extent of effect factors in a system with uncertain information. In this paper, it was applied to evaluate the effect of environmental factors to corrosion of oil tubes in gas wells and find out the main factors. Analysis results of practical data showed that the main factors causing corrosion failure of oil tubes were sweet corrosion and erosion of gas fluids. Failure analysis and experimental research of oil tubes approved the grey relations analysis result, which demonstrated that grey relational analysis method was a good tool for corrosion research and main factors analysis.

Heritability estimates for octyl acetate and octyl butyrate in the mature fruit of the wild parsnip.

The aliphatic esters octyl acetate and octyl butyrate occur as major components of essential oils in the vittae, or oil tubes, of the wild parsnip (Pastinaca sativa). We determined phenotypic variation and narrow-sense heritabilities of these octyl esters in wild parsnip fruits from 30 maternal families. The mean octyl acetate content was 1.56 microg/mg dry fruit (0.08-5.51 microg/mg dry fruit) and the mean octyl butyrate content was 4.28 microg/mg dry fruit (1.28-14.22 microg/ mg dry fruit). Narrow-sense heritabilities for each ester's content were calculated by analysis of half-sib families (HS) and parent-offspring regression (OP). Heritabilities were 0.389 (HS) and 0.654 (OP) for octyl acetate and 0.670 (HS) and 0.626 (OP) for octyl butyrate. The amounts of the esters were phenotypically correlated with each other and with the linear furanocoumarins bergapten and xanthotoxin, phototoxic compounds that co-occur in the vittae with the esters. Ester amounts were not genetically correlated, indicating that these compounds could respond independently to selection pressures. These octyl esters may serve as carrier solvents that enhance penetration of these furanocoumarins into herbivore integuments and gut walls.

Corrsion induced failures of oil tubulars from gas wells in Zhongyuan oil field

Failed oil tubes and the associated corrosion products from gas wells in the Zhongyuan oil field in China were studied by X-ray diffraction, X-ray photoelectron spectroscopy, and electron probe microanalysis. Results showed that CO2 and condensate were primary factors in the corrosion of the tubes. However, non-metallic inclusions in the steel played an important role in accelerating both localised corrosion and cracking in the CO2 containing environment. The possibility of using inhibitors in the gas wells to prevent this sweet gas corrosion was also investigated by means of corrosion tests in the laboratory.

Optimal defence, kin conflict and the distribution of furanocoumarins among offspring of wild parsnip

The factors influencing the allocation of chemical defences to plant offspring have largely been unexplored, conceptually and experimentally. Because evolutionary interactions between maternal plants and their progeny can affect resource allocation patterns among sibling offspring, we suggest that kin conflict as well as herbivore–plant interaction theories need to be considered to predict chemical defence allocation patterns. Optimal defence theory predicts that maternal plants should defend more heavily those offspring in which resources have been disproportionately invested. In contrast, kin conflict theory predicts that natural selection will favour genotypes that can compete successfully for maternal defences irrespective of their quality, even at the expense of the fitness of siblings and the maternal plant. Evidence for these defence patterns were evaluated by examining the allocation of furanocoumarins to seeds of the wild parsnip (Pastinaca sativa, Apiaceae). Furanocoumarins are toxins that are localized within the oil tubes of the maternal tissues of seeds. We evaluated the role of offspring investment (endosperm mass) and seed genotype on furanocoumarin allocation by mating an array of pollen donors with pollen recipients. Furanocoumarins were found to be positively correlated with endosperm mass on one side of the seed, a result consistent with optimal defence theory; however, on the other side of the seed, furanocoumarin content was influenced by seed genotype and was unrelated to endosperm mass. These effects varied with maternal plant. Further experiments demonstrated that nearly 80% of furanocoumarin production occurs after pollination, when fertilization products are active. Although the amount of furanocoumarin influenced by the seed genotype is small relative to the total quantity in the seed, these furanocoumarins are the first line of defence against important predators, such as the parsnip webworm, Depressaria pastinacella (Lepidoptera: Oecophoridae). We found that parsnip webworm larvae were able to discriminate among genotypes within an inflorescence. In line with previous studies, these results suggest that a genotype's ability to influence furanocoumarin defence may affect its probability of survival. We conclude that the distribution of defences among plant offspring in wild parsnip is probably influenced by competition among seed genotypes that conflicts with maternal optimal defence.

Genetic Control of Seed Chemistry and Morphology in Wild Parsnip (Pastinaca sativa)

We attempted to determine whether seed morphology, including the number and size of oil tubes, is genetically variable and serves as a constraint on chemical content

Variation in seed furanocoumarin content within the wild parsnip ( Pastinaca sativa)

Furanocoumarins are restricted within the ripe seeds of Pastinaca sativa, the wild parsnip, to the vittae or oil tubes. The furanocoumarin content and composition of these organs vary with their location. Vittae on the inner or commissural side of the mericarp contained over 90% of the total furanocoumarin content of the seed; the relative abundance of the five furanocoumarin components also varies with seed side. The location of the seed within an umbel does not appear overall to affect furanocoumarin characteristics; however, the location of the seed among umbels is associated with significant differences in furanocoumarin content. The absolute amount of furanocoumarin present in seeds of primary and secondary umbels was approximately twice that of seeds in tertiary umbels. In the case of the wild parsnip, then, furanocoumarin distribution is not homogeneous, either through the plant or within the plant part in which it is localized.

Two New Species of Cymopterus (Umbelliferae) from Western North America

Two species ofCymopterus are described as new:Cymopterus douglassi from the Lost River and Lemhi ranges of central Idaho and the closely relatedC. williamsii from the southern half of the Big Horn Mountains, Wyoming. Both are diploid on the basex=11 and occur on calcareous or dolomitic substrates. The mature fruit ofCymopterus williamsii differ from those ofC. douglassii in the absence of a functioning carpophore and in having 1, not 3–5 oil tubes in the intervals. Both species are unusual in the genus, though not unique, in that the dorsal ribs of the mericarps are not winged.

粘弾性管を用いた液圧管路の周波数応答実験

The purpose of this work is to verify the theoretical analysis obtained by the authors on the propagation of harmonic pressure waves through viscous compressible fluids contained in flexible viscoelastic tubes. A system consisting of hydraulic oil and nylon tubes was used as a hydraulic transmission line. Two nylon tubes of different materials were used in this experimental study. The phase velocity and the damping constant of the pressure waves were measured to determine the viscoelastic model of the tube material. The peripheral strain at a certain point on the tube was measured to verify the viscoelastic model and to clarify the relationship between the fluid pressure and tube radial motion. The frequency response tests of hydraulic transmission lines were carried out and good agreement between experimental and theoretical results was obtained. It is concluded on the basis of the experimental evidence that this theory can describe the dynamic behavior of liquid lines contained in viscoelastic tubes.

Studies in the Umbelliferae. II

Neoparryal n. gen. of the Umbelliferae. Herbaceous, acaulescent perennial. Leaves pinnatisect. Inflorescence spreading; peduncles exceeding the leaves; involucre absent; involucel of small, inconspicuous bracts. Calyx teeth persistent. Stylopodium lacking. Fruit oblong, glabrous; ribs slightly developed; oil tubes small, numerous, scattered in the pericarp; strengthening cells absent. The type species is Neoparrya lithophila,2 n. sp. Plate 33. Seseli Nuttallii Gray, Proc. Am. Acad. 8: 287. 1870, as to Parry collection, No. 83. Plant acaulescent, about 1.5 din. high; leaves petiolate, oblonglanceolate in outline, 8-10 cm. long, about 2.5 cm. broad, somewhat rigid, glabrous, ultimate segments linear, 5-20 mm. long; umbels several-rayed, rays 0.5-1.5 cm. long; involucel bracts linear-lanceolate, about 3 mm. long; styles 2-3 mm. long, persistent; fruit 3-5 mm. long, lateral and dorsal ribs inconspicuous. Type specimen: Dr. C. C. Parry 83, on rocks, Huefano Mountains, New Mexico, Sept. 1867 (TYPE in the Gray Herbarium of Harvard University; isotypes in the Missouri Botanical Garden Herbarium).