The vascular plants (or tracheophytes) are characterized by the presence of vascular tissue (xylem and phloem) for structural support and for long-distance movement of water and nutrients throughout the plant body.
The relationships among the major groups of vascular plants have become clearer in recent years. Investigations into the origin and evolution of the major groups of vascular plants indicate that there is a deep division of the vascular plants into two lineages. One of these lineages includes only the lycophytes (clubmosses, spikemosses, and quillworts), accounting for less than 1% of vascular plant species. The other lineage (known as Euphyllophyta) includes two major clades: the spermatophytes or seed plants (including more than 250,000 species of angiosperms [flowering plants], conifers, cycads, gnetophytes, and the Gingko) and the monilophytes or ferns (sensu lato, including the horsetails, whisk ferns, and eusporangiate and leptosporangiate ferns, with most of the roughly 12,000 monilophyte species being leptosporangiate ferns).
(Pryer et al. 2001; Pryer et al. 2004; Smith et al. 2006; Lehtonen 2011 and references therein)
The horsetails or scouring rushes (Equisetophyta, Sphenophyta, Arthrophyta, and Equisetaceae are among the names that have been used for this group) are now believed to form a monophyletic group with the ferns that is known as the "monilophytes" (although the position of the horsetails within the monilophytes is not yet fully resolved, they may be nested among other ferns);this clade, in turn, is the sister group to the seed plants (Pryer et al. 2001; Schneider et al. 2009 and references therein; Rai and Graham 2010 and references therein). There is just one extant genus, Equisetum, which includes around 15 extant species. Equisetum is nearly cosmopolitan (not native to Australia and New Zealand, but they are exotic weeds there). Many Equisetum have a high silica content and can be used to scour pots (explaining the name "scouring rush"). Horsetails have an extensive and diverse fossil record and several hundred million years ago widespread tree-sized relatives reached 30 m in height (even today, some Equisetum species can reach an impressive size--although nothing approaching 30 m!).
(Mabberley 2008)
For more information on the biology of horsetails, see Husby (2013) and Chad Husby's website.
The relationship of "pteridophytes" to other vascular plants (= tracheophytes) has become clearer in recent years. Investigations into the origin and evolution of the major groups of vascular plants indicate that there is a deep division of the vascular plants into two lineages. One of these lineages includes only the lycophytes (clubmosses, spikemosses, and quillworts). The other lineage includes two major clades: the spermatophytes or seed plants (including more than 250,000 species of angiosperms [flowering plants], conifers, cycads, gnetophytes, and the Gingko) and the monilophytes or ferns (sensu lato, including the horsetails, whisk ferns, and eusporangiate and leptosporangiate ferns, with most of the roughly 12,000 monilophyte species being leptosporangiate ferns). The spermatophytes and monilophytes together comprise a clade known as Euphyllophyta.
Plants in the lycophyte and monilophyte clades are apparently not each other's closest relatives (since the monilophytes are believed to be sister to the seed plants), but because they both produce spores and not seeds, the lycophytes and ferns have traditionally been grouped together in what is now generally recognized to be a paraphyletic group referred to as "pteridophytes" or "ferns and fern allies".
(Pryer et al. 2001; Pryer et al. 2004; Smith et al. 2006; Lehtonen 2011 and references therein)
Vascular plants (from Latin vasculum 'duct'), also called tracheophytes (/trəˈkiː.əˌfaɪts/)[5][6] or collectively Tracheophyta (from Ancient Greek τραχεῖα ἀρτηρία (trakheîa artēría) 'windpipe', and φυτά (phutá) 'plants'),[6] form a large group of land plants (c. 300,000 accepted known species)[7] 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,[8][4]: 251 Tracheobionta[9] and Equisetopsida sensu lato. Some early land plants (the rhyniophytes) had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones.
Historically, vascular plants were known as "higher plants," as it was believed that they were further evolved than other plants due to being more complex organisms. However, this is an antiquated remnant of the obsolete scala naturae, and the term is generally considered to be unscientific.[10]
Botanists define vascular plants by three primary characteristics:
Cavalier-Smith (1998) treated the Tracheophyta as a phylum or botanical division encompassing two of these characteristics defined by the Latin phrase "facies diploida xylem et phloem instructa" (diploid phase with xylem and phloem).[4]: 251
One possible mechanism for the presumed evolution from emphasis on haploid generation to emphasis on diploid generation is the greater efficiency in spore dispersal with more complex diploid structures. Elaboration of the spore stalk enabled the production of more spores and 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.
A proposed phylogeny of the vascular plants after Kenrick and Crane 1997[12] is as follows, with modification to the gymnosperms from Christenhusz et al. (2011a),[13] Pteridophyta from Smith et al.[14] and lycophytes and ferns by Christenhusz et al. (2011b) [15] The cladogram distinguishes the rhyniophytes from the "true" tracheophytes, the eutracheophytes.[12]
Polysporangiates Tracheophytes Eutracheophytes Euphyllophytina Lignophytes Spermatophytes†Pteridospermatophyta (seed ferns)
Cycadophyta (cycads)
Pinophyta (conifers)
Ginkgophyta (ginkgo)
Magnoliophyta (flowering plants)
PteridophytaPteridopsida (true ferns)
Equisetopsida (horsetails)
Psilotopsida (whisk ferns & adders'-tongues)
LycophytinaThis phylogeny is supported by several molecular studies.[14][16][17] Other researchers state that taking fossils into account leads to different conclusions, for example that the ferns (Pteridophyta) are not monophyletic.[18]
Hao and Xue presented an alternative phylogeny in 2013 for pre-euphyllophyte plants.[19]
Polysporangiophytes Tracheophytes Eutracheophytes Microphylls Euphyllophytes Megaphylls Moniliformopses Radiatopses Lignophytes†Progymnosperms
(paraphyletic)
Water 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.
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.[20]
Vascular plants (from Latin vasculum 'duct'), also called tracheophytes (/trəˈkiː.əˌfaɪts/) or collectively Tracheophyta (from Ancient Greek τραχεῖα ἀρτηρία (trakheîa artēría) 'windpipe', and φυτά (phutá) 'plants'), form a large group of land plants (c. 300,000 accepted known species) 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,: 251 Tracheobionta and Equisetopsida sensu lato. Some early land plants (the rhyniophytes) had less developed vascular tissue; the term eutracheophyte has been used for all other vascular plants, including all living ones.
Historically, vascular plants were known as "higher plants," as it was believed that they were further evolved than other plants due to being more complex organisms. However, this is an antiquated remnant of the obsolete scala naturae, and the term is generally considered to be unscientific.
Tracheobionta • Trachéophytes, Trachéobiontes, Plantes vasculaires
Les Trachéophytes (du grec Trakheia, conduit raboteux) ou Trachéobiontes (Tracheobionta), appelées aussi plantes vasculaires associent différentes divisions :
Les caractères principaux sont l'existence de racines et la présence de vaisseaux conducteurs (phloème et xylème contenant des trachéides, d'où le nom de Tracheophyta) assurant la circulation de la sève.
Les Polysporangiophytes sont des plantes apparues à l'Ordovicien et qui sont les premières plantes vasculaires connues[1].
Le groupe des Tracheophyta comprend 391 000 (383 671 espèces selon Ulloa Ulloa et al. publiés dans la revue Science fin 2017[2]) connues en 2015 (dont 369 000 espèces de plantes à fleurs), sachant que près de 2 000 nouvelles espèces sont découvertes par an[3] (dont 744/an [moyenne sur 25 ans, donnée en 2017] rien que pour les Amériques où à la fin de 2017 étaient répertoriées 124 993 plantes vasculaires, classées en 6 227 genres et 355 familles, soit 33 % du total mondial connu[2]).
Le milieu aérien impose des contraintes hydriques par rapport au milieu aquatique pour les plantes qui ont conquis les terres. Les trachéophytes présentent plusieurs traits évolutifs très adaptés à la vie terrestre, notamment l'homéohydrie (leur teneur en eau est maintenue relativement constante pendant toute leur existence[4], quelles que soient les variations de l'état hygrométrique de l'air et de la teneur en eau du sol : cuticule cireuse et spores entourées d’une paroi imprégnée de sporopollénine qui préviennent de la déshydratation par la transpiration ; présence de racines et de vaisseaux conducteurs qui permettent la circulation de l'eau et des nutriments das toutes les parties de la plante ; développement d'un appareil végétatif très ramifié qui permet d'échanger au maximum le dioxyde de carbone et le dioxygène avec l'air[5].
Les classes des nouvelles classifications correspondent à des rangs traditionnellement considérés comme des divisions avec une terminaison en -phyta.
Liste des classes selon ITIS[6] et World Register of Marine Species[7] :
Cycas revoluta (Cycadophyta, cycas)
Ginkgo biloba (Ginkgophyta, ginkgos)
Abies pinsapo (Pinophyta, conifères)
Alsophila lepifera (Pteridophyta, fougères)
Kalmia latifolia (Magnoliophyta, plantes à fleurs)
Reconstitution de Pertica quadrifaria, groupe fossile.
Liste des groupes fossiles selon Novikov & Barabasz-Krasny (2015)[8] :
Ces divisions peuvent, dans les nouvelles classifications, avoir le rang de classe et une terminaison en -opsida au lieu de -phyta.
Phylogénie des ordres actuels de Ptéridophytes d'après le Pteridophytes Phylogeny Group (2016)[9] :
Tracheophyta LycopodiopsidaLycopodiales (Lycopodes)
Isoëtales (Isoëtes)
Selaginellales (Sélaginelles)
Equisetales (Prêles)
Psilotales (Psilotes)
(Spermatophyta, les plantes à graines)
Classification phylogénétique : voir article Archaeplastida (classification phylogénétique).
Depuis plusieurs siècles les flores permettent aux botanistes d'identifier les espèces de trachéophytes qu'ils observent. Les progrès de l'histologie[10], de la phylogénétique [11] la génétique puis l'apparition de l'informatique et de la bioinformatique ou encore la découverte de nouveaux biomarqueurs (cyanogènes par exemple[12]) ont ensuite contribué à l'apparition de nouveaux moyens d'étude et d'identification[13].
Par exemple, en France, au début de 2015[14], la base de données BDTFX, contient un référentiel des trachéophytes de France métropolitaine et des pays voisins, et un index synonymique et nomenclatural de 95 005 noms pour 21 812 taxons. Il est issu de la BDNFF, et a été mis au point par Tela Botanica. Depuis mars 2015, il propose aussi des liens vers la diagnose du nom et renvoie vers le numéro de page correspondante de Flora Gallica.
Pour la France, une nouvelle version (12 octobre 2011) du référentiel des trachéophytes de métropole a été mise en ligne sur le site de l’INPN[15].
En France, la Fédération des conservatoires botaniques nationaux met à disposition du grand public, sur Internet, des données de répartition sur les trachéophytes à travers un atlas national de la flore de France[16].
Tracheobionta • Trachéophytes, Trachéobiontes, Plantes vasculaires
Les Trachéophytes (du grec Trakheia, conduit raboteux) ou Trachéobiontes (Tracheobionta), appelées aussi plantes vasculaires associent différentes divisions :
les Lycophytes (Lycopodes et Sélaginelles) ; les Monilophytes (Fougères et Prêles) ; les Gymnospermes (Conifères, Cycas, Gingko, etc.) ; les Angiospermes (plantes à fleurs).Les caractères principaux sont l'existence de racines et la présence de vaisseaux conducteurs (phloème et xylème contenant des trachéides, d'où le nom de Tracheophyta) assurant la circulation de la sève.
Les Polysporangiophytes sont des plantes apparues à l'Ordovicien et qui sont les premières plantes vasculaires connues.
관다발식물(管다발 植物)은 식물 전체에 물과 미네랄을 전달하기 위해 목질화된 조직(목질부)이 있는 육상 식물로 정의되는 대규모 식물 분류군으로 약 30만 종이 알려져 있다. 관다발식물은 또한 광합성 산물을 수행하기 위해 목질화되지 않은 특수한 조직(체관부)을 가지고 있다. 석송류와 속새류, 양치류, 겉씨식물(침엽수 포함) 및 속씨식물(꽃이 피는 식물)이 포함된다.
다음은 2006년 추(Qiu) 등과 2004년 크레인(Crane) 등의 연구에 의한 유배식물 계통 분류이다.[1][2]
유배식물 관다발식물 진엽식물 종자식물
.jpg)
