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 | | The pathway for solute movement into phloem tissue, the sieve element-companion cell complex (se-ccc), is thought to involve both an apoplastic and a symplastic pathway. | | | In contrast to xylem, phloem transport is much slower, usually <200 cm/h, and intracellular net solute concentrations in phloem are much higher (0.03-0.9M) than in xylem (0.01-0.03 M). | | | In sink tissue, the methods and pathways for solute movement out of phloem tissue are less well understood than mechanisms and pathways for loading. |
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http://www.msu.edu/course/hrt/853/NUTLEC9.html
(1958 words)
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| | Index Phloem |
| | Events occurring in the phloem tissue are key to understand a range of developmental and physiological processes in vascular plants. | | | Phloem functions that take place at different structural and physiological levels requires multiple cross-talks between metabolic, homeostasis and stress responses pathways. | | | The integration of such processes that clearly established the complexity of this tissue will be therefore probably crucial. |
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http://www-biocel.versailles.inra.fr/phloem/poitiers-abst-Dinant.html
(942 words)
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| | Steve's place - Phloem |
| | The pressure flow hypothesis (Münch, 1930) is the most widely accepted theory of phloem transport. | | | This means that any injury is likely to lead to phloem 'haemorrhage'. | | | Bulk flow rate was measured more accurately by Ziegler, who measured rate of movement of a pulse of heat in Heracleum phloem. |
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http://www.steve.gb.com/science/phloem.html
(2015 words)
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| | Phloem - Wikipedia, the free encyclopedia |
| | While movement of water and minerals through the xylem is driven by negative pressures (tension) most of the time, movement through the phloem is driven by positive hydrostatic pressures. | | | The Pressure flow hypothesis was a hypothesis proposed by Ernst Munch in 1930 that explained the mechanism of phloem translocation. | | | This process is termed translocation, and is accomplished by a process called phloem loading and unloading. |
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http://en.wikipedia.org/wiki/Phloem
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| | Index Phloem |
| | Very few developmental mutants affected in the phloem have been described, probably because the screening of such mutants is hard to define. | | | The aim of our research program is therefore to decipher the regulatory network of genes expressed in the phloem in normal conditions of development and in response to stresses. | | | Phloem and xylem derive from a common precursor: the procambium (for primary tissues) and the cambium (for secondary tissues). |
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http://www-biocel.versailles.inra.fr/phloem/Background.html
(610 words)
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| | Translocation of Food |
| | The best-supported theory to explain the movement of food through the phloem is called the pressure-flow hypothesis. | | | Therefore, the osmotic pressure of the contents of the phloem decreases. | | | Translocation through the phloem is dependent on metabolic activity of the phloem cells (in contrast to transport in the xylem). |
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http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/Phloem.html
(815 words)
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| | Phloem - Phloem-specific homeobox gene |
| | Development of concepts and terminology 7 Phloem as a whole 7 - Sieve element 8 - Parenchyma | | | Overview of research activities of Micro- and Protein-Analysis group. | | | Concept of Phloem and its Historical Development 4 11. |
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http://phloem.siteslinks.com
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| | Phloem |
| | How do we know what is in phloem and in what concentrations. | | | Apoplastic pathway is necessary and responsible for buildup of sucrose in sieve element via active transport. | | | We will concentrate on phloem translocation in angiosperms - although you should know that process varies considerably among angiosperms and is quite different in most gymnosperms. |
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http://www.bio.mtu.edu/~mrgretz/bl4140_www/phloem.htm
(753 words)
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| | G7254 Elm Phloem Necrosis, MU Extension |
| | Use our feedback form for questions or comments about G7254. | | | These symptoms are not enough to positively identify phloem necrosis, but the disease can be identified by examining the inner bark. | | | The discoloration of the inner bark and the wintergreen odor are specific symptoms for this disease and serve to differentiate it from all other elm diseases. |
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http://muextension.missouri.edu/xplor/agguides/pests/g07254.htm
(767 words)
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| | xylem,phloem,ducts,laticifers |
| | Sections of living material are usually more difficult to interpret than commercial slides. | | | Phloem may be unstained or may become pink. | | | in the phloem cannot be observed easily without the use of special staining techniques. |
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http://www.botany.hawaii.edu/faculty/webb/BOT410/410Labs/LabsHTML-99/Xylem/Labxyphlo99.html
(1032 words)
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| | Phloem and periderm |
| | You can see the secondary xylem edge and then (outward) the secondary phloem. | | | You can see the general location of the phloem outside of the secondary xylem, but most of the tissues do not show clearly because the section was a little thick. | | | Some thick fibers appear in the secondary phloem, but the large clusters of fibers might be from the primary phloem because the rays do not seem to extend out that far (remember, rays are made by the cambium, not in primary tissues like vascular bundles of primary xylem and phloem). |
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http://biology.unlv.edu/Schulte/BIO426/StudentImages/Phloem/Phloem.html
(361 words)
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| | Root growth and 14C-translocation into the roots of maize |
| | Our experiments, however, demonstrate rather a simultaneous reaction (Fig. | | | According to this hypothesis, phloem unloading leading to endogenous shifts in the phytoholmone balance should occur prior to any morphogenetic effects. | | | It is suggested that phloem mobile phytohormones, especially auxins, lead to an endogenous shift in the phytohormone balance responsible for the morphogenetic effect of a loeal N0 supply. |
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http://www.klaus-thoms.de/satt1.htm
(1865 words)
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| | Phloem Transport |
| | Mechanism of phloem translocation: pressure-flow hypothesis of Ernst Munch (1930) | | | Phloem unloading can also be symplastic or apoplastic | | | Transport of photosynthate occurs mainly in the phloem |
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http://www.esf.edu/efb/course/EFB530/lectures/phloem.htm
(650 words)
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| | phloem |
| | Phloem is usually found in association with xylem, the water-conducting tissue, but unlike the latter it is a living tissue. | | | Phloem is composed of sieve elements and their associated companion cells, together with some sclerenchyma and parenchyma cell types. | | | Phloem tissue is usually found close to the other transport tissue in plants, xylem, which transports water and minerals. |
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http://www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0007061.html
(432 words)
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| | Botany online: Supporting Tissues - Vascular Tissues - Phloem |
| | Phloem elements may be of primary or secondary origin though the early primary phloem, the | | | The main conducting elements of the phloem are the sieve elements, of which there are two different types: | | | The exact number is usually typical for the respective tissue, but it may even vary within a single plant. |
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http://www.biologie.uni-hamburg.de/b-online/e06/06d.htm
(758 words)
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| | ARS Publication request: Phloem and Xylem in the Vascular Sutures of the Soybean Pod |
| | The presence of the inner phloem suggests that it may have a special function in the nourishment of the developing seed. | | | Directly below the sclerenchyma is the vascular tissue with the phloem external to the xylem. | | | However, the anatomy of the xylem and phloem of the pod of the soybean fruiting structure has never been investigated. |
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http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=107405&pf=1
(369 words)
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| | Phloem-1 |
| | Sometimes it is difficult to specifically point out Phloem based on cytology. | | | The Plasmalemma and Cytoplasm are continuous from one STM to another through the Sieve Pores. | | | Furthermore, Phloem cells may have a characteristic organizational pattern |
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http://www.biologie.uni-hamburg.de/b-online/library/webb/BOT311/Phloem/Phloem-1.htm
(257 words)
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| | Translocation in the Phloem |
| | Phloem usually is located outside of the xylem in both primary and secondary vascular systems | | | Comparison of the phloem sieve elements in angiosperms and gymnosperms: | | | Phloem unloading – movement form sieve elements to the sink |
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http://www.hort.purdue.edu/hort/courses/HORT301/MikesLectures/TranslPhloem.html
(1392 words)
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| | FRST 200 - Phloem Transport |
| | According to this theory, sucrose is actively pumped into the phloem at the source (e.g. | | | This in turn raises the pressure potential of the phloem, which then causes mass flow through the sieve cells of the phloem towards the sink (e.g. | | | Note that the actual movement of materials through the phloem does not require metabolic energy, but the loading and unloading of sucrose (and other solutes) does. |
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http://courses.forestry.ubc.ca/frst200/lectures/Phloem.htm
(334 words)
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| | Plant Physiology Online: Classical Studies on Phloem Transport |
| | More sophisticated experiments on phloem translocation became possible in the 1940s, when radioactive isotopes became available for scientific research. | | | In terms of the transport pathway for sugars, the label initially appears in the sieve elements of the phloem, confirming the results of the earlier experiments (Figure 10.1.B). | | | The latter conclusion was based on an observed high correlation between leaf and bark sucrose contents and on the high sucrose concentration calculated to be present in the sieve elements. |
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http://www.plantphys.net/article.php?ch=t&id=130
(697 words)
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| | Ecology: Nitrogen Budgets Of Phloem-Feeding Bark Beetles With And Without Symbiotic Fungi - Statistical Data Included |
| | Nitrogen concentrations increased from 0.40 [+ or -] 0.01% (mean [+ or -] 1 SE) in uninfested phloem to 0.86 [+ or -] 0.03% in the phloeni surrounding successfully developing D. frontalis larvae, which are typically associated with one or two species of mutualistic mycangial fungi. | | | Spatial variation in phloem N was mostly at the level of trees within sites (a scale of meters) while P mostly varied among sites (a scale of kilometers). | | | Phloem nitrogen in one loblolly pine increased to 131% of control levels following the introduction of D. frontalis and associated microorganisms (Hodges et al. |
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http://www.findarticles.com/p/articles/mi_m2120/is_8_81/ai_65197825
(1066 words)
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| | MSN Encarta - Search Results - Phloem |
| | The phloem, or food-conducting tissue, consists of cells that are living at maturity. | | | Phloem, in higher plants, vascular tissue that conducts sugars and other synthesized food materials from the regions of manufacture in the plant to... | | | The principal cells of phloem, the sieve elements, are so... |
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http://ca.encarta.msn.com/Phloem.html
(99 words)
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| | Plant Structure |
| | Parenchyma cells also occur within the xylem and phloem of | | | The two most common cells in the phloem are the | | | Right image is a diagram of the longitudinal view of phloem cells. |
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http://www.estrellamountain.edu/faculty/farabee/biobk/BioBookPLANTANAT.html
(1047 words)
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| | Biology4Kids.com: Plants: Xylem and Phloem |
| | As plants evolved to be larger, they also developed their own kind of circulatory systems. | | | What is the best way to think about phloem? | | | Xylem and phloem make up the big transportation system of vascular plants. |
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http://www.biology4kids.com/files/plants_xylemphloem.html
(380 words)
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| | ipedia.com: Xylem Article |
| | Vessel elements are similar in structure to the sieve-tube members of phloem, but they lack companion cells, and have perforated sides as well as pores at the ends. | | | The cell walls of xylem cellss derive most of their strength from lignin, a chemical compound produced only by plants. | | | Together with phloem, xylem is one of the two transport tissues of plants. |
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http://www.ipedia.com/xylem.html
(343 words)
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| | Phloem |
| | the phloem parenchyma stores compounds such as starch. | | | These cells form the packing tissue between all the other types of cells. | | | the phloem fibres give the plant mechanical strength, |
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http://www.botany.uwc.ac.za/SCI_ED/grade10/plant_tissues/phloem.htm
(196 words)
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| | Search Results for phloem - Encyclopædia Britannica |
| | In the leaf, transpiration, the evaporation of water and taking in of carbon dioxide for photosynthesis, is effected through pores called stomata, which are regulated by valve cells called guard... | | | Features a colored labeled diagram of structure of the vascular tissues. | | | The areas of growth may be newly formed leaves above the photosynthesizing leaves,... |
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http://www.britannica.com/search?query=phloem&submit=Find&source=MWTAB
(368 words)
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| | IngentaConnect How nutritionally imbalanced is phloem sap for aphids? |
| | The phloem sap of early flowering S. oleraceus ingested by U. sonchi contained 48%, which seems to be exceptional. | | | Concentrations of several essential amino acids in phloem from different plant species seem to vary together, suggesting that levels of symbiont provisioning of different amino acids are adjusted in parallel. | | | The profile of the essential amino acids in phloem sap from different plant species corresponds rather well to profiles of both aphid body proteins and optimal diets determined for plant feeding insects. |
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http://www.ingentaconnect.com/content/klu/ento/1999/00000091/00000001/00207746
(409 words)
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| | Section of a leaf |
| | Phloem: conductive tissue that carries sap and other liquids. | | | Stoma: organ of the leaf that allows the exchange of gases. |
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http://www.infovisual.info/01/012_en.html
(71 words)
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