vascular plant

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vascular plant
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{{Automatic taxobox| name = Vascular plants| image = Athyrium filix-femina.jpg
Silurian–Holocene,D. EDWARDS TITLE= RECORDS OF COOKSONIA-TYPE SPORANGIA FROM LATE WENLOCK STRATA IN IRELAND VOLUME= 287 DOI= 10.1038/287041A0 FIRST2= J. 425ref= PARFREY>FIRST1= LAURA WEGENERFIRST2= DANIEL J. G.FIRST3= ANDREW H.FIRST4= LAURA A.JOURNAL= PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICAVOLUME= 108PAGES= 13624–13629PMID= 21810989, 3158185, }}| display_parents = 2| taxon = Tracheophytes/PlantaeBotany. Principles and Problems, 3d edition. McGraw-Hill, New York. ex Thomas Cavalier-Smith>Cavalier-Smith, 1998{{Citation first= T. title= A revised six-kingdom system of life volume= 73 pages= 203–266 weblink >doi= 10.1017/S0006323198005167 }}| subdivision_ranks = Divisions† Extinct| subdivision = }}Vascular plants (from Latin vasculum: duct), also known as tracheophytes (from the equivalent Greek term trachea), form a large group of plants ({{circa}} 308,312 accepted known speciesJOURNAL, Christenhusz, M. J. M., Byng, J. W., yes, 2016, The number of known plants species in the world and its annual increase, Phytotaxa, 261, 201–217,weblink 10.11646/phytotaxa.261.3.1, 3, ) that are defined as those land plants that have lignified tissues (the xylem) for conducting water and minerals throughout the plant. They also have a specialized non-lignified tissue (the phloem) to conduct products of photosynthesis. Vascular plants include the clubmosses, horsetails, ferns, gymnosperms (including conifers) and angiosperms (flowering plants). Scientific names for the group include Tracheophyta,Abercrombie, Hickman & Johnson. 1966. A Dictionary of Biology. (Penguin Books){{rp|251}} TracheobiontaWEB,weblink ITIS Standard Report Page: Tracheobionta, September 20, 2013,


Vascular plants are defined by three primary characteristics:
  1. Vascular plants have vascular tissues which distribute resources through the plant. This feature allows vascular plants to evolve to a larger size than non-vascular plants, which lack these specialized conducting tissues and are thereby restricted to relatively small sizes.
  2. In vascular plants, the principal generation phase is the sporophyte, which produce spores and is diploid (two sets of chromosomes per cell). By contrast, the principal generation phase in non-vascular plants is the gametophyte, which produces gametes and is haploid (one set of chromosomes per cell).
  3. They have true roots, leaves, and stems, even if one or more of these traits are secondarily lost in some groups.
The formal definition of the division Tracheophyta encompasses both these characteristics in the Latin phrase "facies diploida xylem et phloem instructa" (diploid phase with xylem and phloem).{{rp|251}}One possible mechanism for the presumed switch from emphasis on the haploid generation to emphasis on the diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. In other words, elaboration of the spore stalk enabled the production of more spores, and enabled the development of the ability to release them higher and to broadcast them farther. Such developments may include more photosynthetic area for the spore-bearing structure, the ability to grow independent roots, woody structure for support, and more branching.{{citation needed|reason=several points in this paragraph are conjectural and need WP:RS|date=February 2016}}


A proposed phylogeny of the vascular plants after Kenrick and CraneKenrick, Paul & Peter R. Crane. 1997. The Origin and Early Diversification of Land Plants: A Cladistic Study. (Washington, D.C.: Smithsonian Institution Press). {{ISBN|1-56098-730-8}}. is as follows, with modification to the gymnosperms from Christenhusz et al. (2011a),JOURNAL, Christenhusz, Maarten J. M., Reveal, James L., Farjon, Aljos, Gardner, Martin F., Mill, R.R., Chase, Mark W., 2011, A new classification and linear sequence of extant gymnosperms,weblink Phytotaxa, 19, 55–70, 10.11646/phytotaxa.19.1.3, Pteridophyta from Smith et al.JOURNAL, Smith, Alan R., Pryer, Kathleen M., Schuettpelz, E., Korall, P., Schneider, H., Wolf, Paul G., 2006, A classification for extant ferns,weblink Taxon, 55, 3, 705–731, 10.2307/25065646, 25065646, and lycophytes and ferns by Christenhusz et al. (2011b) JOURNAL, Christenhusz, Maarten J. M., Zhang, Xian-Chun, Schneider, Harald, 2011, A linear sequence of extant families and genera of lycophytes and ferns,weblink Phytotaxa, 19, 7–54, 10.11646/phytotaxa.19.1.2, {hide}Barlabel|size=17|at1=5|bar1=green|style=font-size:75%;line-height:75%|label1=Gymnosperms|cladogram={{clade
Polysporangiophyte>Polysporangiates |1={{clade |1={{clade |label1=Tracheophytes |1={{clade |label1=Eutracheophytes |1={{clade |label1=Euphyllophytina |1={{clade |label1=Lignophytes
|label1=Spermatophytes |1={{cladex |1=Pteridospermatophyta â€  (seed ferns) |2=Cycadophyta (cycads)|barbegin2=green |3=Pinophyta (conifers)|bar3=green |4=Ginkgophyta (ginkgo)|bar4=green |5=Gnetophyta|barend5=green |6=Magnoliophyta (flowering plants) {edih} |2=Progymnospermophyta â€  }} |label2=Pteridophyta |2={{clade |1={{clade |1=Pteridopsida (true ferns) |2=Marattiopsida |3=Equisetopsida (horsetails) |4=Psilotopsida (whisk ferns & adders'-tongues) |5=Cladoxylopsida â€  }} }} }} |label2=Lycophytina |2={{clade |1=Lycopodiophyta |2=Zosterophyllophyta â€  }} }} |2=Rhyniophyta â€  }} }} |2=Aglaophyton â€  |3=Horneophytopsida â€  }}}}}}This phylogeny is supported by several molecular studies.JOURNAL, Pryer, K. M., Schneider, H., 2001, Horsetails and ferns are a monophyletic group and the closest living relatives to seed plants, Nature, 409, 6820, 618–22, 10.1038/35054555, 11214320, Smith, AR, Cranfill, R, Wolf, PG, Hunt, JS, Sipes, SD, JOURNAL, Pryer, K. M., Schuettpelz, E., Wolf, P. G., Schneider, H., Smith, A. R., Cranfill, R., 2004, Phylogeny and evolution of ferns (monilophytes) with a focus on the early leptosporangiate divergences, American Journal of Botany, 91, 10, 1582–1598, 10.3732/ajb.91.10.1582, 21652310, Other researchers state that taking fossils into account leads to different conclusions, for example that the ferns (Pteridophyta) are not monophyletic.JOURNAL, Rothwell, G.W., Nixon, K.C., 2006, How Does the Inclusion of Fossil Data Change Our Conclusions about the Phylogenetic History of Euphyllophytes?, International Journal of Plant Sciences, 167, 3, 737–749, 10.1086/503298, yes, {{inconsistent citations, }}

Nutrient distribution

File:ficusxylem.jpg|thumb|upright=1.35|Photographs showing xylem elements in the shoot of a fig tree (Ficus alba): crushed in hydrochloric acidhydrochloric acidWater and nutrients in the form of inorganic solutes are drawn up from the soil by the roots and transported throughout the plant by the xylem. Organic compounds such as sucrose produced by photosynthesis in leaves are distributed by the phloem sieve tube elements.The xylem consists of vessels in flowering plants and tracheids in other vascular plants, which are dead hard-walled hollow cells arranged to form files of tubes that function in water transport. A tracheid cell wall usually contains the polymer lignin. The phloem however consists of living cells called sieve-tube members. Between the sieve-tube members are sieve plates, which have pores to allow molecules to pass through. Sieve-tube members lack such organs as nuclei or ribosomes, but cells next to them, the companion cells, function to keep the sieve-tube members alive.


The most abundant compound in all plants, as in all cellular organisms, is water which serves an important structural role and a vital role in plant metabolism. Transpiration is the main process of water movement within plant tissues. Water is constantly transpired from the plant through its stomata to the atmosphere and replaced by soil water taken up by the roots. The movement of water out of the leaf stomata creates a transpiration pull or tension in the water column in the xylem vessels or tracheids. The pull is the result of water surface tension within the cell walls of the mesophyll cells, from the surfaces of which evaporation takes place when the stomata are open. Hydrogen bonds exist between water molecules, causing them to line up; as the molecules at the top of the plant evaporate, each pulls the next one up to replace it, which in turn pulls on the next one in line. The draw of water upwards may be entirely passive and can be assisted by the movement of water into the roots via osmosis. Consequently, transpiration requires very little energy to be used by the plant. Transpiration assists the plant in absorbing nutrients from the soil as soluble salts.


Living root cells passively absorb water in the absence of transpiration pull via osmosis creating root pressure. It is possible for there to be no evapotranspiration and therefore no pull of water towards the shoots and leaves. This is usually due to high temperatures, high humidity, darkness or drought.{{Citation needed|date=July 2018}}


Xylem and phloem tissues are involved in the conduction processes within plants. Sugars are conducted throughout the plant in the phloem, water and other nutrients through the xylem. Conduction occurs from a source to a sink for each separate nutrient. Sugars are produced in the leaves (a source) by photosynthesis and transported to the growing shoots and roots (sinks) for use in growth, cellular respiration or storage. Minerals are absorbed in the roots (a source) and transported to the shoots to allow cell division and growth.Chapters 5, 6 and 10 Taiz and Zeiger Plant Physiology 3rd Edition SINAUER 2002

See also




  • BOOK, Cracraft, Joel, Donoghue, Michael J., Michael Donoghue, Assembling the Tree of Life,weblink 2004, Oxford University Press, 978-0-19-972960-9, harv,
  • JOURNAL, Cantino, Philip D., Doyle, James A., Graham, Sean W., Judd, Walter S., Walter S. Judd, Olmstead, Richard G., Soltis, Douglas E., Douglas Soltis, Soltis, Pamela S., Pamela Soltis, Donoghue, Michael J., Michael Donoghue, Towards a Phylogenetic Nomenclature of Tracheophyta, Taxon (journal), Taxon, 1 August 2007, 56, 3, 822, 10.2307/25065865, 25065865,
  • JOURNAL, Kenrick, P., The relationships of vascular plants, (Philosophical Transactions of the Royal Society B: Biological Sciences), 29 June 2000, 355, 1398, 847–855, 10.1098/rstb.2000.0619, 1692788, 10905613,
  • BOOK, Pryer, Kathleen M., Schneider, Harald, Magallon, Susana, The radiation of vascular plants, 138–153,weblink {{harvid, Pryer et al, 2004, }}, in {{harvtxt|Cracraft|Donoghue|2004}}
{{Plant classification}}{{botany}}{{Taxonbar|from=Q27133}}{{Authority control}}

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