Equisetopsida: Perbedaan antara revisi

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{{Automatic Taxobox
#ALIH [[Equisetales]]
| fossil_range = {{fossilrange|385|0|Late [[Devonian]]<ref name="Taylor 1993">{{cite book | last= Taylor | first= Thomas N. |author2=Edith L. Taylor. | year= 1993 | title= The Biology and Evolution of Fossil Plants | location= Englewood Cliffs, NJ | publisher= Prentice Hall | pages= 303–305 | isbn= 0-13-651589-4 }}</ref> to Recent}}
| image = Equisetopsida.jpg
| image_alt= A group of small erect plants with unbranched segmented stems. Whorls of small leaves sprout from each segment, thicker at the top end and absent in the lower portion of the stem, giving it the appearance of a bottle brush or a horse's tail.
| image_caption = ''[[Equisetum telmateia]]''
| taxon = Equisetopsida
| authority = C. Agardh
| subdivision_ranks = Ordo
| subdivision =
#ALIH* [[Equisetales]]
**†&nbsp;[[Archaeocalamitaceae]]
**†&nbsp;[[Calamitaceae]]
**[[Equisetaceae]]
* †&nbsp;[[Pseudoborniales]]
* †&nbsp;[[Sphenophyllales]]
| synonyms =
Sphenopsida
}}
 
'''Equisetopsida''', atau '''Sphenopsida''' di kalangan [[paleobotani]], adalah salah satu [[Kelas (biologi)|kelas]] [[tumbuhan berpembuluh]] yang masih lestari hingga kini namun dengan temuan fosil berusia sampai ke kala [[Devon]]. Anggotanya yang banyak dikenal adalah [[paku ekor kuda]] (''Equisetum'')<ref>{{cite web | url = http://www.merriam-webster.com/cgi-bin/dictionary?book=Dictionary&va=horsetail | title = horsetail | work = Merriam-Webster Online Dictionary }}</ref><ref name="Allaby 1999">{{cite book | last= Allaby | first= Ailsa |author2=Michael Allaby | year= 1999 | title= "Sphenopsida." A Dictionary of Earth Sciences }}</ref><ref name=Judd>{{cite book|last1=Judd|first1=W.S.|last2=Campbell|first2=C.S.|last3=Kellogg|first3=E.A.|last4=Stevens|first4=P.F.|last5=Donoghue|first5=M.J.|year=2002|title=Plant systematics, a phylogenetic approach.|publisher=Sinauer Associates, Inc.|location=Sunderland, Massachusetts|isbn=0878934030|page=193 }}</ref>. Kebanyakan anggotanya menyukai tempat yang becek / berair, dengan daun yang sangat tereduksi sehingga fotosintesis dilakukan oleh batang, yang umumnya beruas dan berbentuk berkas-berkas kaku.
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The Equisetopsida were formerly regarded as a separate [[division (biology)|division]] of spore plants and also called '''Equisetophyta''', '''Arthrophyta''' or '''Sphenophyta'''; today they have been recognized as rather close relatives of the typical ferns ([[Pteridopsida]]) and form a specialized lineage of the [[Pteridophyta]].<ref name="Smith 2006">{{cite journal | doi=10.2307/25065646 | last=Smith | first=Alan R.|author2=Kathleen M. Pryer |author3=Eric Schuettpelz |author4=Petra Korall |author5=Harald Schneider |author6=Paul G. Wolf | year=2006 | title= A classification for extant ferns | url=http://www.pryerlab.net/publication/fichier749.pdf | journal=Taxon | volume= 55 | issue=3 | pages= 705–731 | jstor=25065646 }}</ref>
 
==Morphology==
 
The Sphenophytes comprise photosynthesising, "segmented", hollow stems, sometimes filled with pith. At the junction ("node", see diagram) between each segment is a whorl of [[leaf|leaves]]. In the only extant genus ''Equisetum'', these are small leaves ([[microphyll]]s) with a singular vascular trace, fused into a sheath at each stem node. However, the leaves of ''Equisetum'' probably arose by the reduction of [[megaphyll]]s, as evidenced by early fossil forms such as ''[[Sphenophyllum]]'', in which the leaves are broad with branching veins.<ref name=Rutishauser1999>{{cite journal
| author = Rutishauser, R.
| year = 1999
| title = Polymerous Leaf Whorls in Vascular Plants: Developmental Morphology and Fuzziness of Organ Identities
| journal = International Journal of Plant Sciences
| volume = 160
| issue = 6
| pages = 81–103
| url = http://links.jstor.org/sici?sici=1058-5893(199911)160%3A6%3CS81%3APLWIVP%3E2.0.CO%3B2-T
| accessdate = 2008-01-31
| doi = 10.1086/314221
| pmid=10572024
}}</ref>
 
The [[vascular bundle]]s trifurcate at the nodes, with the central branch becoming the vein of a microphyll, and the other two moving left and right to merge with the new branches of their neighbours.<ref name="Stewart and Rothwell"/> The vascular system itself resembles that of the vascular plants' [[eustele]], which evolved independently and [[convergent evolution|convergently]].<ref name="Stewart and Rothwell"/> Very rapid internode elongation results in the formation of a pith cavity and a ring of [[Glossary of botanical terms#carinal canal|carinal canal]]s formed by disruption of the primary [[xylem]]. Similar spaces, the [[Glossary of botanical terms#vallecular canal|vallecular canal]]s are formed in the cortex.<ref name="Stewart and Rothwell"/> Due to the softer nature of the phloem, these are very rarely seen in fossil instances.{{citation needed|date=July 2014}} In the [[Calamitaceae]], secondary xylem (but not secondary [[phloem]]) was secreted as the [[Cambium (botany)|cambium]] grew outwards, producing a woody stem, and allowing the plants to grow as high as 10m. All extant species of ''Equisetum'' are herbaceous, and have lost the ability to produce secondary growth.<ref name="Stewart and Rothwell"/>
 
The underground parts of the plants consist of jointed [[rhizome]]s, from which roots and aerial axes emerge. The plants have [[Meristem#Intercalary meristem|intercalary meristems]] in each segment of the stem and rhizome that grow as the plant gets taller. This contrasts with the seed plants, which grow from an apical meristem - i.e. new growth comes only from growing tips (and widening of stems).
 
Sphenophytes bear cones (technically ''strobili'', sing. [[Glossary of botanical terms#strobilus|strobilus]]) at the tips of some stems. These cones comprise spirally arranged [[Glossary of botanical terms#sporangiophore|sporangiophore]]s, which bear [[Glossary of botanical terms#sporangium|sporangia]] at their edges, and in extant sphenophytes cover the spores externally - like sacs hanging from an umbrella, with its handle embedded in the axis of the cone. In extinct groups, further protection was afforded to the spores by the presence of whorls of [[bract]]s - big pointed microphylls protruding from the cone.
 
The extant horsetails are [[homosporous]], but extinct [[heterospory|heterosporous]] species such as ''Calamostachys casheana'' appear in the fossil record.<ref name=Bower>{{cite book|last=Bower|first=F. O.|origyear=1935|title=The origin of the land flora, a theory based upon the facts of alternation|publisher=Hafner publishing Co.|location=New York|date= 1959|page=381}}</ref> The sporangia open by lateral [[dehiscence (botany)|dehiscence]] to release the spores. The spores bear characteristic [[elater]]s, distinctive spring-like attachments which are [[hygroscopic]]: i.e. they change their configuration in the presence of water, helping the spores move and aiding their dispersal.
 
[[File:Horsetail vegeative stem.JPG|120px|thumb|Vegetative stem: N = node, I = internode, B = branch in whorl, L = fused microphylls]]
[[File:Equisetum strob xs.jpg|thumb|Cross-section through a strobilus; sporangiophores, with attached sporangia (spore capsules) full of spores, can be discerned.]]
[[File:Equisetum telmateia strob.jpg|thumb|Strobilus of ''E. telmateia'', terminal on an unbranched stem]]
 
== Fossil record ==
 
The extant horsetails represent a tiny fraction of Sphenophyte diversity in the past. There were three orders of Equisetopsid; the [[Pseudoborniales]], which first appeared in the late [[Devonian]].<ref name="Taylor 1993" /> Second, the [[Sphenophyllales]] which were a dominant member of the Carboniferous understory, and prospered until the mid and early Permian respectively. The [[Equisetales]] existed alongside the [[Sphenophyllales]], but diversified as that group disappeared into extinction, gradually dwindling in diversity to today's single genus ''[[Equisetum]]''.
 
The organisms first appear in the fossil record during the late Devonian,<ref name=Taylor_1993/> a time when land plants were undergoing a rapid diversification, with roots, seeds and leaves having only just evolved. (See [[Evolutionary history of plants]]) However, plants had already been on the land for almost a hundred million years, with the first evidence of land plants dating to {{Ma|475}}.<ref name="wellman2003">{{cite journal | title = Fragments of the earliest land plants | author = CH Wellman, PL Osterloff, U Mohiuddin | journal = Nature | volume = 425 | issue = 6955 | pages = 282–285 | year = 2003 | url = http://sherpa.leeds.ac.uk/archive/00000106/01/wellmanch1.pdf | pmid = 13679913 | doi = 10.1038/nature01884 }}</ref>
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== Klasifikasi ==
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The horsetails and their fossil relatives have long been recognized as distinct from other seedless vascular plants.<ref name="Eames 1936">{{cite book | last=Eames | first=Arthur J. | year=1936 | title=Morphology of Vascular Plants (Lower Groups) | pages=110–115 | location=New York and London | publisher=McGraw-Hill Book Company }}</ref> Before the advent of modern [[Molecular phylogenetics|molecular studies]], the relationship of this group to other living and fossil plants was considered problematic.<ref name="Bold 1987">{{cite book | last= Bold | first= Harold C. |author2=C. J. Alexopoulos |author3=T. Delevoryas | year= 1987 | title= Morphology of Plants and Fungi | edition= 5th | pages= 371–387, 478, 506–514 | location= New York | publisher= Harper-Collins | isbn= 0-06-040839-1 }}</ref> Because of their unclear relationships, the rank botanists have assigned to the horsetails varies from [[Order (biology)|order]] to [[Division (botany)|division]]. When recognized as a separate division, the literature uses many possible names, including Arthrophyta,<ref name="Bold 1987" /> Sphenophyta,<ref name="Taylor 1993" /><ref name="Gifford and Foster">{{cite book | last=Gifford | first=Ernest M. |author2=Adriance S. Foster | year=1988 | title=Morphology and Evolution of Vascular Plants | edition=3rd | pages=175–207 | location=New York | publisher=W. H. Freeman and Company | isbn=0-7167-1946-0 }}</ref> or Equisetophyta. Other authors have regarded the same group as a class, either within a division consisting of the vascular plants or, more recently, within an expanded fern group. When ranked as a class, the group has been termed the Equisetopsida<ref name="Kenrick 1997">{{cite book | last= Kenrick | first= Paul |author2=Peter R. Crane |year=1997 | title= The Origin and Early Diversification of Land Plants: A Cladistic Study | pages= 241–242 | place= Washington, D. C. | publisher= Smithsonian Institution Press | isbn= 1-56098-730-8 }}</ref> or Sphenopsida.<ref name="Stewart and Rothwell">{{cite book | last= Stewart | first= Wilson N. |author2=Gar W. Rothwell | year= 1993 | title= Paleobotany and the Evolution of Plants | edition= 2nd | location= Cambridge | publisher= [[Cambridge University Press]] | isbn= 0-521-38294-7 }}</ref>
 
Recent [[phylogenetics|phylogenetic analysis]] has produced evidence that this group of plants belongs firmly within the [[fern]] [[clade]] of [[vascular plants]].<ref name="Pryer 2001">{{cite journal | last=Pryer | first=Kathleen M. |author2=Harald Schneider |author3=Alan R. Smith |author4=Raymond Cran |author5=Paul G. Wolf |author6=Jeffrey S. Hunt |author7=Sedonia D. Sipes| year=2001 | title= Horsetails and ferns are a monophyletic group and the closest living relatives to seed plants | url=http://www.pryerlab.net/publication/fichier199.pdf | journal=Nature | volume= 409 | pages= 618–621 | pmid = 11214320 | doi=10.1038/35054555 | issue=6820 }}</ref> A 2006 classification by Smith ''et al.'' places the class Equisetopsida within an unranked clade of broadly defined ferns, as a sister to two classes more traditionally called ferns, Marattiopsida and Polypodiopsida.<ref name="Smith 2006"/>
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Hubungan antarkelompok di dalam Equisetopsida menurut salah satu versi ditunjukkan dengan kladogram berikut<ref>{{cite web|title=Introduction to the Sphenophyta|url=http://www.ucmp.berkeley.edu/plants/sphenophyta/sphenophyta.html|publisher=University of California Museum of Paleontology|accessdate=31 July 2011}}</ref>.
{{clade|style=line-height:100%;
|1={{clade
|1=†''[[Pseudobornia ursina]]''
|2={{clade
|1=†[[Sphenophyllales]]
|2={{clade
|1=†[[Archeocalamitaceae]]
|2={{clade
|1=†[[Calamitaceae]]
|2={{clade
|1=[[Equisetaceae]]
}}
}}
}}
}}
}}
}}
<!-- [[File:Equisetopsida.png|thumb|A phylogenetic tree showing probable relations within Equisetopsida<ref>{{cite web|title=Introduction to the Sphenophyta|url=http://www.ucmp.berkeley.edu/plants/sphenophyta/sphenophyta.html|publisher=University of California Museum of Paleontology|accessdate=31 July 2011}}</ref> ]] -->
 
==Referensi==
{{Reflist}}
 
{{Wikispecies|Equisetopsida}}
{{Commons category|Equisetopsida}}
{{Plant classification}}
 
[[Category:Equisetopsida| ]]
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