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Topic: Coleoptile

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	Entwicklungsbiologie - Was ist eine Coleoptile?
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		Bei der Keimung schiebt sich die Coleoptile (auch genannt: Keimblattscheide) nach oben und durchbricht den Boden.
		Im Folgenden ist die Keimung einer Maispflanze gezeigt, bei der die Rolle der Coleoptile deutlich wird:
	www.dev-biologie.de /glossdex/coleoptile/coleoptile.htm (68 words)

	Botany of the wheat plant - E.J.M. Kirby
		Tl1 is the tiller borne in the axil of leaf 1 of tiller 1.
		The tiller borne in the axil of the prophyll is coded P: thus TCP is the tiller in the axil of the prophyll of the coleoptile tiller.
		The buds in the axil of the coleoptile and of leaf 1 are present in the embryo.
	www.fao.org /docrep/006/y4011e/y4011e05.htm (7988 words)

	Early Corn Development
		The coleoptile is the protective point of the emerging shoot, and is the only part which can penetrate soil.
		The coleoptile orients the direction of the shoot toward the warmth of the soil surface and protects the miniature plant until it emerges.
		As soon as the tip of the coleoptile is exposed to sunlight, it splits and allows the leaves to extend into the sunlight.
	www.wyffels.com /pages/early_corn_development.html (670 words)

	Plant Physiology Online: The Coleoptile Chloroplast
		When corn coleoptiles are given a saturating red-light pretreatment and a blue-light pulse in the presence of increasing concentrations of DTT (an inhibitor of zeaxanthin formation), bending and zeaxanthin content decrease linearly as a function of DTT concentration (see Web Figure 18.4.A, Part 3).
		Thus the relationship between the zeaxanthin content of coleoptile chloroplasts and blue light—dependent phototropic sensitivity is very similar to the relationship between the zeaxanthin content of the guard cell chloroplast and the blue-light sensitivity of stomatal opening.
		Coleoptile and guard cell chloroplasts share some properties that are clearly distinct from mesophyll chloroplasts, including high rates of oxygen evolution and low rates of photosynthetic carbon fixation, a high sensitivity of their xanthophyll cycle to low levels of incident photon fluxes, and a high starch content (Zhu et al.
	www.plantphys.net /article.php?ch=18&id=179 (545 words)

	/usr6/usr3/httpd_1.3/htdocs/agronomy/papers/246/246w.temp.html
		A reduction in coleoptile length leads to poor emergence when seed is sown deep such as when soil moisture near the surface is insufficient for germination, or when planting equipment is improperly adjusted.
		Coleoptile length was recorded as the distance from the seed to where the first leaf broke through the coleoptile sheath.
		Ease of selection for plant height and coleoptile length in populatioÿs containing GA-sensitive, height-reducing genes indicates the potential of these genes for the rapid development of long coleoptile wheats in breeding programs targeting the development of wheats with improved emergence for deep sowing and conservation tillage-based farming systems.
	www.csu.edu.au /special/agronomy/papers/246/246w_new.html (2020 words)

	IITA/CIMMYT Research Guide (Site not responding. Last check: )
		Elongation of the first internode (mesocotyl; Figure 4) pushes the coleoptile upward towards the soil surface.
		The coleoptile is the fine green shoot observed when maize is first emerging from the ground.
		The coleoptile should not be confused with true leaf number 1 which has a rounded tip.
	www.iita.org /info/trn_mat/irg9/irg903.htm (573 words)

	Emergence and Establishment Problems of Hulless Barley – A Possible Solution.
		Coleoptile lengths were shorter for ‘Visually Whole Embryo’ than ‘Husk Intact’ which suggests that it will be difficult to avoid any embryo damage despite our modifications to harvest and seed cleaning procedures.
		A superior hulless barley coleoptile was produced for all four hulless barley genotypes when the palea and lemma remained intact after harvesting and threshing.
		Chromosome regions involved in the control of coleoptile length were identified on chromosome 7H in the Chebec x Harrington population and on chromosome 5H in the Galleon x Haruna nijo population.
	www.regional.org.au /au/abts/1999/box.htm (2339 words)

	GRDC - Advice Sheets - Improving seed emergence (Dec 2000) (Site not responding. Last check: )
		Once the root has emerged the coleoptile, which is a sheath that encases the first leaf, pushes through the soil to the surface.
		If the coleoptile is shorter than the sowing depth, the first leaf must try to push through the soil and emerge in a dark environment.
		Coleoptile lengths differ between wheat varieties and many of the older wheats had long coleoptiles, so could be sown at more variable and greater depths.
	www.grdc.com.au /growers/as/seed_emergency.htm (1258 words)

	The Emergence Process in Corn (Purdue Univ.) (Site not responding. Last check: )
		The mesocotyl is the tubular, white, stemlike tissue connecting the seed and the base of the coleoptile.
		As the coleoptile nears the soil surface, exposure of the mesocotyl to the red light portion of the solar radiation spectrum halts mesocotyl elongation.
		Since the depth at which the mesocotyl senses red light is fairly constant, the resulting depth of the crown (base) of the coleoptile is nearly the same (1/2 to 3/4 inch) at seeding depths of one-inch or greater.
	www.agry.purdue.edu /ext/corn/news/articles.02/Emergence_Process-0520.html (634 words)

	Untitled
		The coleoptile is a sheath of tissue that surrounds and protects the embryonic shoot in grasses until it above ground; it is especially sensitive to the direction from which light is coming and therefore is a good experimental tissue to use in the study of phototropism.
		In (a) the control coleoptile is shown undergoing the events described as phototropism - the coleoptile on this oat seedling is bending so as to grow toward the source of the light coming from the right side.
		(f) shows that partial division of the coleoptile allows for lateral migration (away from the direction of the light) and an accumulation of auxin on the shady side of the stem.
	www.botany.uga.edu /~darley/btny1210/Oct19Mon.htm (1431 words)

	ARS \| Publication request: Covariation for Microsatellite Marker Alleles Associated with Rht8 and Coleoptile Length in ... (Site not responding. Last check: )
		Coleoptiles for cultivars containing the Rht8 diagnostic marker were not significantly longer than those without the marker.
		Since coleoptile elongation may be controlled by several genes, using Rht8 gene alone may not be sufficient to select coleoptile length in a semidwarf plant type.
		Since coleoptile elongation may be controlled by several quantitative trait loci, identifying only the presence of 192-bp allele of Xgwm 261 may be misleading if the primary motivation for its deployment is to increase coleoptile length in a semidwarf plant type.
	www.ars.usda.gov /research/publications/publications.htm?seq_no_115=153463 (758 words)

	A breeding solution to improving seedling establishment of wheat
		Shorter coleoptiles also compromise emergence with direct drilling or stubble retention in conservation tillage (3,4), or when soil temperatures are high (8).
		Differences in coleoptile length were small and nonsignificant (P>0.05) among populations but large and significant (P<0.01) for lines within populations (Table 1).
		Given the high heritability for coleoptile length (h2 = 0.85-0.88) and plant height (h2 = 0.63-0.73) long coleoptile, reduced height wheats could be developed readily via a two-stage or simultaneous selection strategy for each character in a breeding program.
	www.regional.org.au /au/asa/1998/5/246rebetzke.htm (2207 words)

	Fox Seed Germination
		The coleoptile is enlarged, elongated and curving slightly upward (top right), while the coleorhiza has completely emerged (center left), as has the trichome hairs (center left) and the radicle (lower left).
		The coleoptile is enlarged, elongated and curving slightly upward (left center), while the coleorhiza has completely emerged (center right), as has the trichome hairs (center right) and the radicle (upper right).
		The emergence of the coleoptile (center; the shoot) from the distal end of the seed, between the lemma (top) and the palea (bottom), the two parts of the seed hull.
	www.agron.iastate.edu /~weeds/Fox/FoxSeed/germination.html (371 words)

	Seedling (Site not responding. Last check: )
		The mesocotyl or basal portion of the coleoptile elongates when the seed germinates in soil, and in darkness.
		It pushes the coleoptile above the soil surface.
		It is differentiated into a leaf blade and a leaf sheath.
	www.knowledgebank.irri.org /RP/morph/Seedling.htm (67 words)

	Herbicide-tolerant Germplasm in Rice
		The mesocotyl and coleoptile were measured after the petri dishes were placed in a temperature controlled germination chamber for seven days at 28°C. Abnormal or diseased seedlings were determined for percent germination but the mesocotyl and coleoptile lengths were not measured because of abnormal growth and development of these seedlings.
		Alachlor is absorbed primarily through the mesocotyl and coleoptile tissue of the seedling and ultimately disrupts the development of the radicle, secondary roots, and primary leaves (Pillai et al.
		Furthermore, the elongation potential of the mesocotyl and coleoptile is heritable and varies according to the genetic constitution of the germplasm (Dilday et al.
	www.hort.purdue.edu /newcrop/proceedings1990/V1-146.html (1694 words)

	Cold weather stresses corn; herbicide injury possible \| Integrated Crop Management
		Reports are widespread across Iowa and the symptoms have been variously described as a "toughened" coleoptile or membrane that does not allow the seedling corn plant to emerge properly.
		The result of a coleoptile that fails to "release" the developing leaves is a plant that "cork screws" underground, or leaves that rupture out of the coleoptile on the side rather than emerging through the tip.
		The problems with the coleoptile are primarily the result of the cold and wet conditions.
	www.ipm.iastate.edu /ipm/icm/node/17 (651 words)

	Acid phosphatase isozymes in root, coleoptile and callus tissues of inbreds and their hybrids (Site not responding. Last check: )
		Isozymes of acid phosphatase were studied under different developmental stages, such as root and coleoptile, in vivo and at the callus stage in vitro in 5 inbreds, Tuxp162-1, Tuxp237-2, Tuxp104-2, MS1DR-120, PKMS1-49, and 4 hybrid genotypes, Tuxp162-1xTuxp237-2, Tuxp237-2xTuxp124-1, Tuxp104-2xTuxp46-6, MS1DR-120xPKMS1-49.
		Coleoptile tissues of inbreds Tuxp162-1, Tuxp237-2 and their hybrid had identical isozyme bands showing the same isozyme pattern, but they differed in the intensity of isozyme activity.
		Inbreds Tuxp162-1, Tuxp237-2 and their hybrid had the same bands, except for the absence of the A-8 band in the latter inbred and a difference in intensity of bands.
	www.maizegdb.org /mnl/66/146kumar.html (436 words)

	USGS/NBII CSWGCIN - Regional Invasive Species - Bibliography (Site not responding. Last check: )
		Coleoptile and mesocotyl elongation were greatest in 2.5 and 5{percent} oxygen, and shortest in anoxia.
		Rapid S. alterniflora coleoptile and mesocotyl elongation in anoxia enables its seedlings to escape the impact of the stressful environment where its seeds can germinate, but the seedlings could not survive otherwise.
		This suggested oxygen was produced inside the coleoptile by the photosynthesizing plumule, and triggered root development.
	cswgcin.nbii.gov /(ha30rj55eub02d55erezfj45)/issues/invasives/speciesbiblio.aspx?CitationID=293&tsn=41072 (470 words)

	Diagnosing Early Corn Development Problems
		The first is simply excess light striking the coleoptile before it has emerged completely from the soil.
		This causes the side of the coleoptile to rupture, allowing the leaves to exit while underground.
		These herbicides can weaken the coleoptile wall, causing it to rupture very similar to what you see from cold weather and crusting, but you will see twisting or “cork screwing” of the coleoptile and the mesocotyl.
	www.wyffels.com /pages/diagnose_corn_dev.html (808 words)

	Auxins
		The coleoptile is a specialized leaf originating from the first node which sheaths the epicotyl in the plants seedling stage protecting it until it emerges from the ground.
		Darwin's experiment suggested that the tip of the coleoptile was the tissue responsible for perceiving the light and producing some signal which was transported to the lower part of the coleoptile where the physiological response of bending occurred.
		In 1913, Boysen-Jensen modified Fritting's experiment by inserting pieces of mica to block the transport of the signal and showed that transport of auxin toward the base occurs on the dark side of the plant as opposed to the side exposed to the unidirectional light (Boysen-Jensen, 1913).
	www.plant-hormones.info /auxins.htm (1334 words)

	Corn leaf aphids in seedling corn
		The research findings, published in the Journal of Economic Entomology, were as follows: Plants infested in the coleoptile and two-leaf stage were the most sensitive to aphid feeding; however, the expression of this damage may have been modified by cool spring conditions or drought conditions.
		The plants infested in the coleoptile and two-leaf stage had larger reductions in grain fill than did plants infested in the four-leaf stage, suggesting that these growth stages were more sensitive to aphid feeding.
		In summary, feeding by corn leaf aphids on coleoptile and two-leaf stage plants delayed plant development, reduced plant height, and delayed pollen shed and silking.
	www.ipm.iastate.edu /ipm/icm/2003/5-19-2003/cornleafaphids.html (468 words)

	Depth of Seedling (Site not responding. Last check: )
		Deep seeding requires greater seedling vigor, reduced number of seeds that emerge and may eliminate the emergence of the coleoptile tiller.
		The coleoptile is a leaf sheath which surround and protects the first true leaf as it grows from the seed towards the surface.
		If the coleoptile is shorter than the depth of planting, emergence will become difficult.
	www.ext.nodak.edu /county/stark/spotlite/seedeep.htm (141 words)

	bending
		The coleoptile of the same seedlings on exposure to unidirectional light bent towards the light source.
		However, if the coleoptile tip was removed or covered by an opaque cap, coleoptiles did not bend towards light.
		The action spectra of oat coleoptile phototropism showed two prominent peaks at 475 and 450 nm with a shoulder at 420 nm.
	members.tripod.com /phototropism/photo1.htm (2718 words)

	American Journal of Botany, 28, 1, January, 1941 (Site not responding. Last check: )
		When coleoptile tips have stopped giving off auxin by diffusion, they still contain auxin which can be obtained by extraction (table 3, B).
		Thus by combining the method of exhaustive diffusion and exhaustive extraction, a way is found by which the auxin precursor in coleoptiles can be determined quantitatively (by converting it into active auxin).
		coleoptile tips is: Zea 92 per cent; water cultured Avena 86 per cent; sand cultured Avena 48 per cent of the potential auxin content.
	www.botany.org /ajb/00029122_di001388.php (2091 words)

	Botany online: Plant hormones - Phytohormones - Auxins (Site not responding. Last check: )
		A growing coleoptile that is illuminated unilaterally does grow towards the light source.
		Studies of plant anatomical nature revealed that the growth towards light is caused by an elongation of the cells at the side that is shielded from the light.
		In the late twenties was the material nature of the effector finally proved by the Dutch plant physiologist F. He assumed that a substance that flows from tip to bottom should also flow through a small cube of agar.
	www.biologie.uni-hamburg.de /b-online/e31/31b.htm (971 words)

	Rupert Sheldrake Online
		A re-examination of the evidence for auxin production by coleoptile tips reveals that it is not conclusive and that several important problems remain unresolved.
		The possibility that auxin and auxin precursors move acropetally in the xylem was tested by analysing guttation fluid from intact coleoptiles, decapitated coleoptiles and primary leaves of Avena sativa.
		Experiments on the movement of dyes and radioactive IAA introduced into the xylem of transpiring or guttating coleoptiles showed that these substances accumulate at the tip of the coleoptile, or at the apical region of decapitated coleoptiles.
	www.sheldrake.org /papers/Hormone/auxin_coleoptile_abs.html (186 words)

	peo-8 (Site not responding. Last check: )
		In 1996-97, four laboratory trials were carried out to investigate the effect of temperature, the period of growth and the effect of humidity on the expression of potential coleoptile length.
		In order to define a minimum coleoptile length necessary for adequate crop establishment in the field, a trial was conducted at three sites in 1997 (Biloela, Gatton and Roma) and in the glass house at Gatton to observe the effect of different sowing depth on seedling establishment in a conventional tillage system.
		The potential coleoptile lengths of 53 cultivars from seed grown from four sites in 1996 have been measured to observe the stability of the coleoptile length of the cultivars across the sites.
	www.newcrops.uq.edu.au /people/peo-8.htm (396 words)

	Vitaflo C - It's all grow with Vitaflo
		Does not retard the growth of the coleoptile of the germinating seed, improving emergence.
		The coleoptile is a sheath that guides the germinated shoot through the soil to the surface.
		The coleoptile is critical to getting the crop out of the ground quickly.
	www.hannafords.com /product.php?id=7 (844 words)

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