Contents 1 Chemical composition 2 Physical properties 3 Epicuticular wax crystals 4 References 5 Further reading


Chemical composition[edit] Common constituents of epicuticular wax are predominantly straight-chain aliphatic hydrocarbons that may be saturated or unsaturated and contain a variety of functional groups. Paraffins occur in leaves of peas and cabbages, alkyl esters in leaves of carnauba palm and banana, the asymmetrical secondary alcohol 10-nonacosanol in most gymnosperms such as Ginkgo biloba and Sitka spruce, many of the Ranunculaceae, Papaveraceae and Rosaceae and some mosses, symmetrical secondary alcohols in Brassicaceae including Arabidopsis thaliana, primary alcohols (mostly octacosan-1-ol) in most grasses Poaceae, Eucalyptus and legumes among many other plant groups, β-diketones in many grasses, Eucalyptus, box Buxus and the Ericaceae, aldehydes in young beech leaves, sugarcane culms and lemon fruit and triterpenes in fruit waxes of apple, plum and grape[1][2] Aromatic compounds have been recorded in epicuticular waxes but are generally minor constituents.


Physical properties[edit] Epicuticular wax crystals surrounding a stomatal aperture on the lower surface of a rose leaf. These compounds are mostly solids at ambient temperature, with melting points above about 40 C (104 F). They are soluble in organic solvents such as chloroform and hexane, making them accessible for chemical analysis, but in some species esterification of acids and alcohols into estolides or the polymerization of aldehydes may give rise to insoluble compounds. Solvent extracts of cuticle waxes contain both epicuticular and cuticular waxes, often contaminated with cell membrane lipids of underlying cells. Epicuticular wax can now also be isolated by mechanical methods[3] that distinguish the epicuticular wax outside the plant cuticle from the cuticular wax embedded in the cuticle polymer. As a consequence, these two are now known to be chemically distinct,[4] although the mechanism that segregates the molecular species into the two layers is unknown. Recent scanning electron microscopy (SEM), atomic force microscopy (AFM) and neutron reflectometry studies [5] on reconstituted wax films have found wheat epicuticular waxes; made up of surface epicuticular crystals and an underlying, porous background film layer to undergo swelling when in contact with water, indicating the background film is permeable and susceptible to the transport of water. Epicuticular wax can reflect UV light, such as the white, chalky, wax coating of Dudleya brittonii, which has the highest ultraviolet light (UV) reflectivity of any known naturally occurring biological substance.[6]


Epicuticular wax crystals[edit] Epicuticular wax forms crystalline projections from the plant surface, which enhance their water repellency,[7] create a self-cleaning property known as the lotus effect[8] and reflect UV radiation. The shapes of the crystals are dependent on the wax compounds present in them. Asymmetrical secondary alcohols and β-diketones form hollow wax nanotubes, while primary alcohols and symmetrical secondary alcohols form flat plates[9][10] Although these have been observed using the transmission electron microscope[9][11] and scanning electron microscope[12][13] the process of growth of the crystals had never been observed directly until Koch and coworkers[14][15] studied growing wax crystals on leaves of snowdrop (Galanthus nivalis) and other species using the atomic force microscope. These studies show that the crystals grow by extension from their tips, raising interesting questions about the mechanism of transport of the molecules.


References[edit] ^ Baker, EA (1982) Chemistry and morphology of plant epicuticular waxes. In: The Plant Cuticle(eds DJ Cutler, KL Alvin, and CE Price), Academic Press, London, pp. 139-165 ^ Holloway, PJ and Jeffree, CE (2005) Epicuticular waxes, Encyclopedia of Applied Plant Sciences, 3, pp. 1190-1204 ^ Ensikat, HJ, Neinhuis, C, & Barthlott, W. (2000) Direct access to plant epicuticular wax crystals by a new mechanical isolation method. International Journal of Plant Sciences, 161, 143-148 ^ Jetter, R, Schäffer, S, and Riederer, M (2000) Leaf cuticular waxes are arranged in chemically and mechanically distinct layers: evidence from Prunus laurocerasus L. Plant, Cell and Environment, 23, 619-628 ^ Pambou E, Li Z, Campana M, Hughes A, Clifton L, Gutfreund P, Foundling J, Bell G, Lu JR. 2016 Structural features of reconstituted wheat wax films. J. R. Soc. Interface 13: 20160396. https://dx.doi.org/10.1098/rsif.2016.0396 ^ Mulroy, Thomas W. (1979). "Spectral properties of heavily glaucous and non-glaucous leaves of a succulent rosette-plant". Oecologia. 38 (3): 349–357. doi:10.1007/BF00345193.  ^ Holloway, PJ (1969) The effects of superficial wax on leaf wettability, Annals of Applied Biology, 63, 145-153 ^ Barthlott, W & Neinhuis, C (1997) Purity of the sacred lotus, or escape from contamination in biological surfaces. Planta 202, 1-8 ^ a b Hallam, ND (1967) An electron microscope study of the leaf waxes of the genus Eucalyptus L'Heritier, PhD thesis, University of Melbourne ^ Jeffree, CE, Baker, EA, and Holloway, PJ (1975) Ultrastructure and recrystallisation of plant epicuticular waxes. New Phytologist, 75, 539–549. ^ Juniper, BE & Bradley, DE (1958) The carbon replica technique in the study of the ultrastructure of leaf surfaces, Journal of Ultrastructure Research, 2, 16–27 ^ Jeffree, CE (2006) The fine structure of the Plant Cuticle. Chapter 2 In: Riederer, M & Müller, C, eds (2006) Biology of the Plant Cuticle. Blackwell Publishing. pp 11–125. ^ Riederer, M & Müller, C, eds. (2006) Biology of the Plant Cuticle. Blackwell Publishing ^ Koch, K, Neinhuis, C, Ensikat, HJ, and Barthlott, W (2004) Self assembly of epicuticular waxes on living plant surfaces imaged by atomic force microscopy (AFM). Journal of Experimental Botany, 55, 711–718 ^ Koch, K, Barthlott, W, Koch, S, Hommes, A, Wandelt, K, Mamdouh, H, De-Feyter, S and Broekmann P (2005) Structural analysis of wheat wax (Triticum aestivum, c.v. 'Naturastar' L.): from the molecular level to three dimensional crystals Planta, 223, 258–270


Further reading[edit] Eigenbrode, S.D. (1996) Plant surface waxes and insect behaviour, in Plant Cuticles: an integrated functional approach, (ed G. Kerstiens), Bios Scientific Publishers, Oxford, pp. 201-221. Retrieved from "https://en.wikipedia.org/w/index.php?title=Epicuticular_wax&oldid=813640887" Categories: Plant anatomyPlant physiology


Navigation menu Personal tools Not logged inTalkContributionsCreate accountLog in Namespaces ArticleTalk Variants Views ReadEditView history More Search Navigation Main pageContentsFeatured contentCurrent eventsRandom articleDonate to WikipediaWikipedia store Interaction HelpAbout WikipediaCommunity portalRecent changesContact page Tools What links hereRelated changesUpload fileSpecial pagesPermanent linkPage informationWikidata itemCite this page Print/export Create a bookDownload as PDFPrintable version Languages CatalàEspañolFrançais中文 Edit links This page was last edited on 4 December 2017, at 13:53. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Developers Cookie statement Mobile view (window.RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgPageParseReport":{"limitreport":{"cputime":"0.096","walltime":"0.124","ppvisitednodes":{"value":333,"limit":1000000},"ppgeneratednodes":{"value":0,"limit":1500000},"postexpandincludesize":{"value":2170,"limit":2097152},"templateargumentsize":{"value":80,"limit":2097152},"expansiondepth":{"value":7,"limit":40},"expensivefunctioncount":{"value":0,"limit":500},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 98.897 1 -total"," 65.86% 65.138 1 Template:Reflist"," 46.40% 45.885 1 Template:Cite_journal"," 24.01% 23.748 1 Template:For"," 1.85% 1.831 1 Template:Main_other"]},"scribunto":{"limitreport-timeusage":{"value":"0.033","limit":"10.000"},"limitreport-memusage":{"value":1488326,"limit":52428800}},"cachereport":{"origin":"mw1261","timestamp":"20171226200434","ttl":1900800,"transientcontent":false}}});});(window.RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgBackendResponseTime":96,"wgHostname":"mw1265"});});


Epicuticular_wax - Photos and All Basic Informations

Epicuticular_wax More Links

EfflorescenceWaxPlant CuticleLand PlantsAliphaticHydrocarbonFunctional GroupAliphaticHydrocarbonAlkanePeaCabbageEsterCarnaubaBananaSecondary AlcoholGymnospermsGinkgo BilobaSitka SpruceRanunculaceaePapaveraceaeRosaceaeMossesSecondary AlcoholBrassicaceaeArabidopsis ThalianaPrimary AlcoholOctacosan-1-olPoaceaeEucalyptusLegumeDiketoneEucalyptusBuxusEricaceaeAldehydeBeechSugarcaneLemonTriterpeneApplePlumGrapeEnlargeChloroformHexaneCell MembranePlant CuticleScanning Electron MicroscopyAtomic Force MicroscopyNeutron ReflectometryDudleya BrittoniiUltraviolet LightReflectivityLotus EffectUVSecondary AlcoholCarbon NanotubePrimary AlcoholSecondary AlcoholTransmission Electron MicroscopeScanning Electron MicroscopeSnowdropGalanthusAtomic Force MicroscopeDigital Object IdentifierHelp:CategoryCategory:Plant AnatomyCategory:Plant PhysiologyDiscussion About Edits From This IP Address [n]A List Of Edits Made From This IP Address [y]View The Content Page [c]Discussion About The Content Page [t]Edit This Page [e]Visit The Main Page [z]Guides To Browsing WikipediaFeatured Content – The Best Of WikipediaFind Background Information On Current EventsLoad A Random Article [x]Guidance On How To Use And Edit WikipediaFind Out About WikipediaAbout The Project, What You Can Do, Where To Find ThingsA List Of Recent Changes In The Wiki [r]List Of All English Wikipedia Pages Containing Links To This Page [j]Recent Changes In Pages Linked From This Page [k]Upload Files [u]A List Of All Special Pages [q]Wikipedia:AboutWikipedia:General Disclaimer



view link view link view link view link view link