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Topic: Tracheid


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  tracheid
A tracheid is elongated, with tapering ends and thick, lignified (see lignin), and pitted walls.
It is a long, empty, firm-walled tube running parallel with the long axis of the organ in which it lies, overlapping and in communication with adjacent tracheids by means of pits.
Tracheids are characteristic of vascular plants other than flowering plants.
www.daviddarling.info /encyclopedia/T/tracheid.html   (148 words)

  
  Tracheid - Wikipedia, the free encyclopedia
Tracheids are long tubular cells in the wooden parts of plants.
Tracheids have two major functions, structural support and transport of water and minerals collected by the roots.
The presence of tracheids (and other water-conducting cells) is the defining characteristic of vascular plants to differentiate them from non-vascular plants.
en.wikipedia.org /wiki/Tracheid   (210 words)

  
 TRACHEID FACTS AND INFORMATION   (Site not responding. Last check: 2007-11-06)
Tracheids are elongated cells in the xylem of vascular plants, serving in the transport of water.
Tracheids are one of two types of tracheary elements, vessel elements being the other.
Because tracheids have a much higher surface to volume ratio compared to vessel elements, they serve to hold water against gravity (by adhesion) when transpiration is not occurring.
www.bellabuds.com /tracheid   (223 words)

  
 Tracheid -- Facts, Info, and Encyclopedia article   (Site not responding. Last check: 2007-11-06)
Tracheids have two major functions, particularly in structural support and the conduction of water and soil minerals collected by the roots to the upper parts of the plants.
Tracheids are located in the (The woody part of plants: the supporting and water-conducting tissue, consisting primarily of tracheids and vessels) xylem, along with wooden vessel elements.
The presence of tracheids (and other water-conducting cells) is the defining characteristic of (Green plant having a vascular system: ferns, gymnosperms, angiosperms) vascular plants to differentiate them from (Click link for more info and facts about non-vascular plant) non-vascular plants.
www.absoluteastronomy.com /encyclopedia/t/tr/tracheid.htm   (199 words)

  
 Microscopic Wood Anatomy
The marginal cells are tracheids with bordered pits which are smaller than the bordered pits of the axial tracheids of earlywood.
Tracheid with helical fissures in the wall structure.
This phenomenon is not useful as an identification characteristic as it is frequent in compression wood and altered wood of many coniferous species.
www.woodanatomy.ch /mic_trach.html   (93 words)

  
 Tracheid   (Site not responding. Last check: 2007-11-06)
A Tracheid is the basic unit of the xylem (fluid-conducting tissue), consisting of a single elongated cell with a wall composed of cellulose thickened with lignin.
The mature tracheids form a column of superposed, cylindrical dead cells whose end walls have been perforated, resulting in a continuous tube called vessel (trachea).
Tracheids are found in all vascular plants and are the only conducting elements in gymnosperms and ferns.
www.cactus-art.biz /note-book/Dictionary/dictionary_tracheid.htm   (141 words)

  
 The mechanism of tracheid cavitation in the trees infected with wilting diseases   (Site not responding. Last check: 2007-11-06)
This indicates that abnormal dehydration from tracheids was occurring in the infected trees.
Tracheids in those areas were filled with air and had become dysfunctional.
Kuroda, K. Responses of Quercus sapwood to infection with the pathogenic fungus of a new wilt disease vectored by the barkbeetle Platypus quercivorus.
cse.ffpri.affrc.go.jp /keiko/hp/IUFRO2001.htm   (1835 words)

  
 tracheid --  Encyclopædia Britannica
Characteristic of most flowering plants and absent from most gymnosperms and ferns, vessels are thought to have evolved from tracheids (a primitive form of water-conducting cell) by loss of the end walls.
The cells of the vascular strands in pteridophytes are mainly tracheids, sieve cells, parenchyma, and endodermal cells.
The tracheids, which comprise the xylem, or water-conducting tissue, are normally long, narrow, and attenuated at the tips.
www.britannica.com /eb/article-9073120   (518 words)

  
 Tracheid - Palaeos   (Site not responding. Last check: 2007-11-06)
Tracheids were narrow, closed-ended, long, and mostly had some living cell associated with them.
To complicate matters further, in plants with vessels, the tracheids may have specialized as structural support tissues (biological rebar).
In plants without vessels, tracheids often differ strongly between vessel-like earlywood and latewood tracheids.
www.palaeos.org /Tracheid   (165 words)

  
 The tracheid-vessel element transition in angiosperms involves multiple independent features: cladistic consequences -- ...
the evolution of a vessel from a tracheid.
(2) Conductive area of the end wall of the (wider) earlywood tracheid (at right in the pair at left) is greater than that of pits of tracheid lateral walls because the pits are larger on the end walls; this is interpreted as an incipient form of vessellike structure.
Although tracheids are monomorphic in length in a vesselless wood (left), vessel-bearing woods have vessel elements shorter than the imperforate tracheary elements they accompany (right).
www.amjbot.org /cgi/content/full/89/2/185   (5757 words)

  
 EJPAU 2005. PAZDROWSKI W. , SZABAN J. EFFECT OF THE REDUCTION OF THE ASSIMILATION APPARATUS FOLLOWING THE PRUNING ...
The length of tracheids was measured from each bore hole on the first increment before the pruning treatment (1950), on the increment from the year of pruning (1951) as well as on the second, third, sixth, eleventh and forty fourth increments after pruning.
Using the analysis of variance to compare mean tracheid lengths of the late wood between individual reduction variants separately for each year, it was possible to notice a lack of variation of the mean tracheid lengths between individual reduction variants for 1950 and highly significant differences in all the remaining years.
Perhaps the causes of the rapid increase of the length of tracheids should be sought in the decrease of the vital capabilities of trees to such an extent that they were threatened with death resulting from their inability to compensate for the removed crown assimilation surface by the reserve substances found in wood.
www.ejpau.media.pl /volume8/issue2/art-35.html   (3208 words)

  
 Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers
Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers
Tracheids with a critical diameter greater than 43 µm were calculated to embolize in response to freezing and thawing at a xylem pressure of –0.5 MPa.
The air saturation method simulated the effect of increased tracheid size because the degree of super-saturation is proportional to a tracheid volume holding an equivalent amount of dissolved air at ambient pressure.
heronpublishing.com /tree/summaries/volume23/a23-907.html   (334 words)

  
 Olympus Microscopy Resource Center: Specialized Microscopy Techniques - Phase Contrast Photomicrography Gallery - ...
Tracheids are nonliving cells found in the xylem of the more ancient plant types, seedless vascular plants (ferns, club mosses, and horsetails) and gymnosperms (cedar, pine, and cypress trees).
As plants moved from the aquatic realm to land, some of them developed internal vascular structures that carried water and nutrients throughout the increasingly complex plant body.
Interestingly, tracheids don't become functional until they are dead and empty.
www.olympusmicro.com /primer/techniques/phasegallery/tracheidcells.html   (271 words)

  
 Stem & Root Anatomy
Tracheids and vessels become hollow, water-conducting pipelines after the cells are dead and their contents (protoplasm) has disintegrated.
Because the summer tracheids are smaller and more dense, they appear as dark bands in a cross section of a log.
The structural strength and hardness of woody monocots is due to clusters of heavily lignified tracheids and fibers associated with the vascular bundles.
waynesword.palomar.edu /trjune99.htm   (2137 words)

  
 literature database   (Site not responding. Last check: 2007-11-06)
Tracheids differentiated in explants only when actively differentiating tracheids were already present at the moment of explanting, suggesting the absence of factors necessary for tracheid differentiation in over-wintering tissues.
This apparently is the first report of induction of compression-wood tracheid differentiation in the absence of hormone treatment or tilting of trees.
No evidence for new tracheid differentiation was seen in control cuttings; however, the results suggest that neither cambial cell division nor tracheid differentiation were actually initiated by IAA.
dendrome.ucdavis.edu /literature/literature_detail.php?id=Savidge_0018-2214_1983_447_66   (416 words)

  
 Nondestructive estimation of tracheid length from sections of radial wood strips by near infrared spectroscopy
The fibers in these sections were characterized in terms of arithmetic and length-weighted mean tracheid length using a fiber quality analyzer, and calibrations with NIR spectra were developed for both measures of tracheid length.
) of 0.88 for arithmetic tracheid length and 0.96 for length-weighted tracheid length.
The accuracy of NIR predicted length-weighted tracheid length was sufficient for ranking purposes.
www.srs.fs.usda.gov /pubs/20108   (351 words)

  
 Botany online: Supporting Tissues - Vascular Tissues - Xylem
It consists of tracheary elements, tracheids and wood vessels and of additional xylem fibres.
Tracheids are regarded as the prototype of prosenchymatic cells, since the cell's ends are pointed and true final walls are missing.
Tracheids look often square in cross-section, the lignified secondary wall is relatively thin.
www.biologie.uni-hamburg.de /b-online/e06/06b.htm   (856 words)

  
 ANATOMY OF - Online Information article about ANATOMY OF   (Site not responding. Last check: 2007-11-06)
When, in place of a number of such cells called tracheids, we have a continuous tube with the same kind of wall thickening, but composed of a number of cells whose cross walls have disappeared, the resulting structure is called a vessel.
The tracheids or vessels, indifferently called tracheal elements, together with the immediately associated cells (usually amylom in Pteridophytes) constitute the xylem of the plant.
The sieve-tubes differ, however, from the tracheids in being immediately associated, apparently constantly, not with starchy parenchyma, but with parenchymatous cells, containing particularly abundant proteid contents, which seem to have a function intimately connected with the conducting function of the sieve-tubes, and which we may call proteid-cells.
encyclopedia.jrank.org /ALM_ANC/ANATOMY_OF.html   (9698 words)

  
 Information on Wood Quality, Properties and Utilization of Southern Pines   (Site not responding. Last check: 2007-11-06)
Thus, the physical and mechanical properties of wood tracheids or fibers are dominated by the microfibrils and it angles in the secondary wall, especially in the thick S2 layer.
A negative linear correlation between fibril angles in LW tracheids and growth rings from pith was observed by Hiller (1954) in fast-growth Slash pine and slow-growth trees also had high angles near the pith but the relationship was curvilinear and the turn was at 10-13th rings  (Figure 6).
The tracheid length in Loblolly pine as related to number of rings from pith and unextracted specific gravity of wood (Figure 12) was reported by McMillin (1968).  His observation revealed that the tracheid length increased as tree age increased and LW tracheids are longer than EW tracheids.
www.forestry.auburn.edu /sfnmc/class/tangwood.htm   (2341 words)

  
 Amazon.com: "tracheid length": Key Phrase page   (Site not responding. Last check: 2007-11-06)
Silvae Genet 18:57-61 Elliott GK 1966 Tracheid length and specific gravity distribution in Sitka spruce.
Some of the effects can be examined using wood density and tracheid length as examples.
There is strong evidence of a negative genetic cor- relation between growth rate and wood density.
amazon.com /phrase/tracheid-length   (391 words)

  
 Tracheid length prediction in Pinus palustris by means of near infrared spectroscopy: the influence of age   (Site not responding. Last check: 2007-11-06)
Tracheid length prediction in Pinus palustris by means of near infrared spectroscopy: the influence of age
This can happen since tracheid length is not directly related to the absorbance at any wavelength but is instead the result of a seondary correlation with some unknown chemical constituent.
In this work, the effect of tree age and height on NIR predictability was investigated since tracheid length and chemistry may vary as a function of location within the tree.
www.urbanforestrysouth.usda.gov /pubs/20973   (351 words)

  
 Unasylva - No. 73-74 - FAO/IUFRO meeting on forest genetics - 9. Breeding for wood properties in forest trees
In nearly every instance, notably with tracheid length and tracheid widths but with the major exception of cellulose yields, inheritance in both the broad sense and narrow sense is quite strong.
The individual wood fiber or tracheid is the "basic unit" usually employed in describing wood morphology (from a genetical standpoint).
In most instances, tracheid lengths of progeny were intermediate to that of the parents, but in some instances length seemed to be influenced more by the female than the male parent.
www.fao.org /docrep/03650e/03650e0a.htm   (11080 words)

  
 [No title]   (Site not responding. Last check: 2007-11-06)
Araucarioxylon (1.5% of specimens) is characterised by dominantly multiseriate, alternately arranged bordered pitting on radial tracheid walls and by 1-4 araucarioid cross-field pitting.
Araucariopitys (11.8% of specimens) is characterised by dominantly uniseriate tracheid pitting with subordinate biseriate, alternate tracheid pitting and by 1-4 araucarioid cross-field pitting.
1 (63.1% of specimens) is characterised by contiguous, uniseriate tracheid pitting and 1-2 podocarpoid cross-field pits.
www.elsevier.com /cdweb/journals/00346667/articles/111/1-2/S003466670000012.abstract.en   (272 words)

  
 MICROSCOPIC FRAGMENTS OF MESOZOIC CONIFER WOOD FOUND IN THE KIMMERIDGE CLAY AND PURBECK SEDIMENTS AND RELATED TOPICS
This picture of a conifer bordered pit tracheid structure was derived from the Jurassic, Lower Purbeck, Cypris Freestones, Micrite and Clay Layer.
Bordered Pit tracheid structures : These characteristic microscopic features were found among the wood fusain fragments in the Kimmeridge Clay and the Purbeck beds on cellulose lacquer rock peels.
They are pits in the walls of the elongated xylem tracheid cells adapted for conduction of water, as part of the transpiration mechanism.
www.microscopy-uk.org.uk /mag/artmay99/kamast4.html   (2424 words)

  
 Landrum, James Victor.   (Site not responding. Last check: 2007-11-06)
Wide-band tracheids (WBTs) are found in leaves and stems of species in the South African genus Anacampseros (Portulacaceae).
Wide-band tracheids are parenchyma cells that are converted into modified tracheids with wide secondary walls intruding into the lumen.
In the GA seedlings, three of four measured traits remained similar with the exception of the cell area occupied by the wide-band, which increased from a mean of 72% in the control seedlings to a mean of 81% in the GA seedlings.
www.ou.edu /cas/botany-micro/botany2000/section2/abstracts/21.shtml   (215 words)

  
 WPS 202. Pits   (Site not responding. Last check: 2007-11-06)
If the air bubble were able to spread from tracheid to tracheid or vessel to vessel, then water conduction would be ended.
Tracheid to tracheid pit membranes in conifers have a different construction than vessel-vessel pit membranes.
The pit membrane of tracheid to tracheid pits is differentiated into a torus a central thickened area) and a margo.
www.uwsp.edu /papersci/biasca/ps350/Pits.html   (659 words)

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