Wax Mass Research Articles

Influences of air humidity during the cultivation of plants on wax chemical composition, morphology and leaf surface wettability

Changes of cuticular wax morphology, chemistry, and wettability of Brassica oleracea (Brassicaceae), Eucalyptus gunnii (Myrtaceae) and Tropaeolum majus (Tropaeolaceae), with different types of surface waxes, cultivated at three levels of relative air humidities (RH) (a: 20–30%, b: 40–75% and c: 98% RH) have been investigated. Wax chemistry was investigated by gas chromatography (GC) and mass spectroscopy (MS), micro morphology by scanning electron microscopy (SEM) and surface wettability by measuring the contact angle. Grown at 98% RH, all species showed decreased total wax mass and wax crystal density but significantly increased leaf surface wettability. In contrast cultivation at 20–30% RH led to increased total amounts of wax and reduced surface wettability. SEM investigations and GC/MS analysis revealed that wax crystal morphology and qualitative wax composition of Brassica were altered after cultivation at 98% RH, whereas chemical composition and morphology of wax crystals in Tropaeolum and Eucalyptus remained unchanged.

Changes in strain and deposition of cuticle in developing sweet cherry fruit

Changes in surface area, deposition and elastic strain of the cuticular membrane (CM) were monitored during development of sweet cherry (Prunus avium L.) fruit. Fruit mass and surface area ('Sam') increased in a sigmoidal pattern between 16 and 85 days after full bloom (DAFB) with maximum rates of 0.35 g day(-1) and 0.62 cm(2) day(-1), respectively. Rates of total area strain, namely the sum of elastic plus plastic strain, were highest in cheek and stem cavity regions followed by stylar and suture regions. Rates of total uniaxial strain were higher in transverse, namely perpendicular to the stem/stylar axis, than in longitudinal direction, namely parallel to the stem/stylar axis. On a whole fruit basis CM mass remained essentially constant during fruit development. Mass of CM, dewaxed CM and wax per unit surface area decreased during development, particularly between 43 and 71 DAFB. There was no change in wax content of isolated CM. Up to 43 DAFB the surface area of isolated CM was similar to the area prior to excision indicating little elastic strain, but markedly decreased thereafter. Calculating elastic and plastic components of total strain of the CM revealed, that initial deformation up to 22 to 43 DAFB was mostly plastic. Thereafter, elastic strain was evident and both, elastic and plastic deformation, increased linearly with an increase in total strain. There was no consistent difference in the relative contribution of elastic strain to total strain between transverse and longitudinal directions, but both total and elastic strain were larger in the transverse direction. Abrading the CM had only little effect on fruit turgor. However, turgor decreased when the exocarp was cut indicating that the exocarp provided a significant structural shell of a mature sweet cherry fruit ('Regina'). Our data demonstrate, that (1) surface area expansion in sweet cherry fruit causes elastic and plastic strain of the CM, and (2) the onset of elastic strain coincided with the cessation of CM formation.

Herbicide efficacy, leaf structure, and spray droplet contact angle amongIpomoeaspecies and smallflower morningglory

Abstract Greenhouse and laboratory studies were conducted to evaluate responses of ivyleaf morningglory, pitted morningglory, palmleaf morningglory, and smallflower morningglory to several herbicides in relation to leaf structure, epicuticular wax, and spray droplet behavior. Two- to four-leaf stage plants of each species were highly susceptible to acifluorfen, bentazon, bromoxynil, glufosinate, and glyphosate. However, at the five- to eight-leaf stage, these species were less susceptible, and control was herbicide specific. Spray droplets of these five herbicides had a higher contact angle on ivyleaf morningglory than the other three species with a few exceptions. Stomata and glands were present on both adaxial and abaxial leaf surfaces of all species, and palmleaf morningglory and smallflower morningglory had more of these than did the other two species. Trichomes were present on all species except palmleaf morningglory. Epicuticular wax mass was highest in ivyleaf morningglory (57 μg cm−2) and lowest i...

Characterization of leaf surface, wax composition, and control of redvine and trumpetcreeper with glyphosate

Abstract Laboratory and greenhouse studies were conducted on redvine and trumpetcreeper to characterize leaf surface and wax composition, determine responses of these weeds to glyphosate, characterize the nature of interactions between glyphosate and several selective postemergence herbicides (e.g., acifluorfen, bentazon, chlorimuron, imazaquin, and pyrithiobac) used in soybean and cotton, and determine the effects of various adjuvants on glyphosate activity on both species. Trumpetcreeper was consistently more susceptible to glyphosate than redvine. Glyphosate spray solution droplets had lower contact angle in trumpetcreeper than in redvine. Micro-roughness of the trumpetcreeper adaxial leaf surface was greater due to trichomes and glands compared to that of redvine, which had no trichomes or glands. Stomata or crystal wax deposition on the adaxial leaf surface were not observed in either species. The wax mass per unit area (22 to 37 µg cm−2) was similar regardless of the leaf age in both species. Epicut...

Comb-wax discrimination by honeybees tested with the proboscis extension reflex.

We used the proboscis extension reflex of honeybees to test their ability to discriminate between comb waxes of different ages (wax scales, 1-week-old wax, 2- to 3-year-old wax, 8- to 10-year-old wax). Such waxes differ in their chemical composition, and an ability to discriminate between them may aid the orientation of the bees in the nest. To train the bees, we used whole extracts of waxes and four different fractions of the whole extract based on different elutions of solid-phase extractions (extract I, fraction A eluted with hexane and fraction B with diethylether; extract II, fraction B further subdivided into fraction C by elution with isopropylchloride and fraction D by elution with diethylether). In a differential training regime (six learning and six test trials) with whole extracts or with the different fractions, we paired one type of wax with a reward and another with no reward. The bees learned to discriminate between all tested pairs of whole extracts. The two subfractions (fractions A and B) gave different results: the bees could discriminate between waxes of different ages when fraction B was used but not when fraction A was used. A further subdivision of fraction B into fractions C and D showed that only fraction D contained the elements that enabled bees to discriminate between old and new wax. Fraction D makes up only 5?8 % of the total wax mass and contains hydroxy alkyl esters (5?6 % of the total wax mass), primary alcohols (0.3?0.5 % of the total wax mass) and acids (0.06?1. 0 % of the total wax mass). Fractions A and C (together forming 62?64 % of the total wax mass), which consist of unbranched and branched aliphatic hydrocarbons and alkyl esters, could not be discriminated by the bees. The remaining wax mass (25?29 %) was eluted with a mixture of chloroform, methanol and water (13:5:1) as fraction E.

A scanning electron microscope study of the genus Calyptrochilum Kraenzl. (Orchidaceae) in West Africa

AbstractA scanning electron microscope (SEM) study of leaf patterns in Calyptrochilum Kraenzl. was carried out in search of constant taxonomic characters. Calyptrochilum chrystyanum (Rchb.) Summerh. is characterized by a network of horizontal grooves, dome shaped micropapillae and a mass of soft wax, while C. emarginatum (Sw.) Schltr. is distinguished by the presence of densely overlapping conical and globular types of micropapillae. Sculpturing features in the genus are characteristic and therefore of utility in identifying even sterile specimens and fragments. An attempt is made to relate the observed surface patterns to distribution, ecology and habitat tolerance.

A Comb-Wide Web

Honeybees as master engineers—the proof is in the honeycomb. A mathematical proof by Thomas Hales, reported in Dana Mackenzie's News of the Week article “Proving the perfection of the honeycomb” (27 Aug., p. [1338][1]), shows that honeybees make optimal use of wax and space in the construction of their combs. Such calculations are based on the geometry of the comb cells and hence take into account only the wax in the thin walls of the cells. However, about 30% (in some cases up to 50%) of the total wax mass of a comb is contained in the relatively thick rims found around the upper edges of each open cell ([1][2]). These rims constitute another optimally adapted structure—a superficial “net” that extends over the entire comb and transmits vibrations across its face. Vibrations are produced by a honeybee dancer during her “waggle dance,” the famous behavioral phenomenon by which bees inform their nestmates about the location of food sources. We found that these vibrations are carried exclusively by the net spread across the surface of the cells. The resonant properties of the comb as a whole are such that two frequency bands at around 15 hertz and 260 hertz are optimally transmitted and even amplified ([2][3]). These two frequencies are precisely those produced by the honeybee dancer during the waggle phase of her dance. Honeycombs are not only optimally engineered in terms of minimal wax use for maximum space, they are also perfectly engineered for communication purposes. 1. [↵][4]1. H. Vogt , Festschrift zur Jahrhundertfeier der Universitcat Breslau 207 (1911). 2. [↵][5]1. D. C. Sandeman 2. et al. , J. Exp. Biol. 199, 2585 (1996). [OpenUrl][6][Abstract/FREE Full Text][7] [1]: /lookup/doi/10.1126/science.285.5432.1338 [2]: #ref-1 [3]: #ref-2 [4]: #xref-ref-1-1 View reference 1 in text [5]: #xref-ref-2-1 View reference 2 in text [6]: {openurl}?query=rft.jtitle%253DJournal%2Bof%2BExperimental%2BBiology%26rft.stitle%253DJ.%2BExp.%2BBiol.%26rft.issn%253D0022-0949%26rft.aulast%253DSandeman%26rft.auinit1%253DD.%26rft.volume%253D199%26rft.issue%253D12%26rft.spage%253D2585%26rft.epage%253D2594%26rft.atitle%253DTransmission%2Bof%2Bvibration%2Bacross%2Bhoneycombs%2Band%2Bits%2Bdetection%2Bby%2Bbee%2Bleg%2Breceptors%26rft_id%253Dinfo%253Apmid%252F9320517%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [7]: /lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NjoiamV4YmlvIjtzOjU6InJlc2lkIjtzOjExOiIxOTkvMTIvMjU4NSI7czo0OiJhdG9tIjtzOjI1OiIvc2NpLzI4Ni81NDQ4LzIyNjkuNS5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=

Composition and Variability of Epicuticular Waxes in Apple Cultivars

Variation in amount and composition of epicuticular wax among several apple (Malus ×domestica Borkh.) cultivars was characterized by gas chromatography, thin-layer chromatography, and gas chromatography-mass spectroscopy. Across cultivars, wax mass ranged from 366 to 1038 μg·cm-2. Wax mass decreased during the 30 days before harvest. Ursolic acid accounted for 32% to 70% of the hydrocarbons that make up the epicuticular wax. Alkanes, predominantly 29-carbon nonacosane, comprised 16.6% to 49%. Primary alcohols of the hydrocarbons ranged from 0% to 14.6% of the epicuticular wax. Secondary alcohols of the hydrocarbons were the most cultivar specific, making up 20.4% of the epicuticular wax in `Delicious' and only 1.9% `Golden Delicious' strains. Aldehydes and ketones of the hydrocarbons represented a small amount of total wax, ranging from 0% and 6.0%. Percentage of primary alcohol in the epicuticular wax increased as fruit developed. Other components showed no distinct trends with fruit development. Examination of the ultrastructure of cuticular wax using scanning electron microscopy revealed structural differences among cultivars.

Paraffin Plombage of the Chest Revisited

Complications related to previous thoracic plombage procedures are not uncommon. The management of these complications can be challenging. We present a patient who had a partial resection of the left upper lobe, a seven-rib thoracoplasty, and paraffin wax plombage 38 years previously, in whom a chest wall mass and a discharging sinus developed. She underwent excision and debridement of the paraffin wax mass followed by serratus anterior and latissimus dorsi pedicled muscle intrathoracic transposition. Follow-up at 2 years revealed excellent cosmetic and functional results.

Ablation by pulsed plasma jets

The ability of pulsed plasma jet igniters to evaporate liquid fuel when cold-starting alcohol- and diesel-fueled automobile engines is investigated using solid samples of wax (which is thermally similar to alcohol), polymethylmethacrylate and glass. The known properties of the plasma jet imply a potential rate of heat transfer from the jet to an adjacent surface of the order of 108 W m-2. The computed flux thresholds for evaporation of wax and polymethylmethacrylate are of the order of 107-108 W m-2 and in fact a mass evaporation of 10-9-10-8 kg per pulse is measured. The threshold for glass is in excess of 108 W m-2 and no evaporation is observed. The mass of wax evaporated is in good agreement with calculations made on the basis of a self-limiting mechanism in which an insulating layer of vapour is established at the surface through an equilibrium between evaporation of material into the layer and convection of plasma into the layer.

Effects of Filtered Air and Misting Treatments on Cuticles of Red Spruce Needles on Whiteface Mountain, N.Y.

wo sets of large (8-20 m tall) red spruce (Picea rubens Sarg.) trees growing on Whiteface Mountain, N.Y., were used in branch chamber experiments. In the summer of 1988, the treatments were made on four healthy trees and consisted of: (1) open branches (N), and in chambers that were supplied with either: (2) ambient air (A); (3) charcoal-filtered air (T); or (4) charcoalfiltered air and deionized water misting when the forest was immersed in ambient cloud water (M). Each tree had all of the treatments. The treatments for the second year (summer of 1989) were made on four declining trees and consisted of: (1) open branches (NC) and chambers supplied with either (2) ambient air and mist (AA), (3) synthetic acid mist and ambient air (SA), (4) distilled water mist and ambient air (DA), (5) synthetic acid mist with filtered air (SF), and (6) distilled water mist with filtered air (DF). Foliar properties measurcd included: (1) microreflectivity, a measure of surface wax properties; (2) cuticle thickness; (3) cutinized cell wall thickness; (4) total cuticular layer thickness: (5) the mass of surface wax extracted from needle samples; and (6) contact angles, a measure of surface wetting. In addition, needles were collected and measured from healthy trees at lower and higher elevations. In the first experiment, reflectance from the wax in the stomata1 antechambers in treatment M was statistically significantly greater than all the other treatments. The cuticles of needles in treatment M were also statistically significantly thicker than the cuticles measured in all the other treatments (40% thicker than for the open branches). A plot of cuticular layer against elevation showed that the two filtered chambers (M and T) provided environments for cuticle development that mimic lower elevations. In 1989 the weather was cooler and more moist, and although the trees used in 1989 were declining, the results were similar to those of 1988. However, the additional treatments with synthetic acid mist resulted in reduced cuticle thickness. While the cuticles of the chamber trees growing at 1,170 m were, except for treatment M and T, generally thicker in 1989 than in 1988, they were still considerably thinner than those of spruce trees growing at the lower elevations. These results suggest regional scale air and precipitation quality have detrimental effects on red spruce needles at Whiteface Mountain.

Parametric sensitivity studies using paraffin wax storage sub-systems

Performance estimates are compared for a solar assisted domestic hot water ststem with a yearly reference load of 13.7 GJ(3811 kWhryr −1) for storage subsystems of pure water and hybrid water and wax systems. Three models of the hybrid system are used ranging from the infinite heat transfer model, the detailed heat transfer model and the simplified constant Nusselt number model. Sensitivity studies are made for changes in collector type (loss coefficient), collector area, mass of water stored, mass of wax stored, heat exchanger gap spacing, and thermal properties of wax. The optimal heat exchanger gap spacing is established for a particular prototype wax store on hand and its performance figure is given. Although the conclusion is drawn that a paraffin wax store in this particular application would not replace water as a storage medium, other conclusions are discussed which would apply to the design and modelling of wax storage subsystems in other applications.

Wax Secretion in the Rhizobiini.*

When Lindorus lophanthae (Blaisdell) and Rhizobius ventralis (Er.) are reared in the laboratory they produce wax at every stage of their life cycle subsequent to the first larval instar. The amount of wax secreted during the feeding period is only sufficient to give the larva a powdery appearance. After the larva has finished feeding and is in the prepupal stage the amount of wax is greatly increased. Rhizobius is then completely covered with a mass of cottony wax. The fine long filaments of wax give it the appearance of having been attacked by mold. The dorsum of Lindorus is covered with tufts of wax but is not completely hidden. The outer row of six longitudinal rows of wax glands produces wax most abundantly.

REPRODUCTION OF THE UPPER AIR-PASSAGES BY PLATING CASTS OBTAINED BY THE CORROSION METHOD.Read in the Section on Laryngology and Otology, at the Forty-fourth Annual Meeting of the American Medical Association.

While it is no new thing to obtain, in metal or other materials, casts of the cavities or structures of the body, and exquisite results have been long and by many workers obtained in this field, there yet remains much to be thus demonstrated to the scientific world at large, and far more in the way of local demonstration. It is with this latter object that I desire here to bring forward some of my results, believing that they will be new to some and interesting to others who work in the upper air tract. Made in fusible metal, which can be readily cast into the soft tissues of the recent cadaver, these metal casts have a delicacy and a durability far superior to anything which is possible with the more frequently used wax mass; and the secondary process which I have here employed has marked advantages and seems to