17:
171:. Overall, about 100 species are known to occur as autotrophs in lichens. All the algae and cyanobacteria are believed to be able to survive separately, as well as within the lichen; that is, at present no algae or cyanobacteria are known which can only survive naturally as part of a lichen. Common algal partners are
518:
Scientists have successfully replicated lichenization in the laboratory; it takes anywhere from a few months to a few years for the isolated fungus and photobiont of a lichen to grow back into a complete thallus. It is unclear how long the process takes in the wild. Throughout lichenization (and
382:
produced by a given fungal symbiont with its differing partners will be similar, and the secondary metabolites identical, indicating that the fungus has the dominant role in determining the morphology of the lichen. Further, the same algal species can occur in association with different fungal
224:
Both the lichen and the fungus partner bear the same scientific name, and the lichens are being integrated into the classification schemes for fungi. Depending on context, the taxonomic name can be meant to refer to the entire lichen, or just the fungus that is part of the lichen.
538:
Some of these parasitic lichenolous fungi form their own thalli and become lichen themselves; they are called "lichenicolous lichens". They steal the symbioant of another lichen (kleptosymbiosis) into their own structure (trans-lochenization).
148:. In return, the fungal partner benefits the algae or cyanobacteria by protecting them from the environment by its filaments, which also gather moisture and nutrients from the environment, and (usually) provide an anchor to it.
433:
Although the photobionts are almost always green algae (Chlorophyta), sometimes the lichen contains
Cyanobacteria, taxonomically bacteria, and sometimes both types of photobionts are found in the same lichen.
383:
partners. Lichens are known in which there is one fungus associated with two or even three algal species. Rarely, the reverse can occur, and two or more fungal species can interact to form the same lichen.
502:
The fungus and the alga start in the environment, apart from each other. Each part produces chemical signals to help the other part find it. At this point, the fungus displays increased hyphae branching.
378:
A particular fungus species and algal species are not necessarily always associated together in a lichen. One fungus, for example, can form lichens with a variety of different algae. The
486:. These lichen species are grey-blue, especially when dampened or wet. Many of these characterize the Lobarion communities of higher rainfall areas in western Britain, e.g., in the
86:
symbionts occurring in lichens are a wide variety of simple, photosynthetic organisms commonly and traditionally known as “algae”. These symbionts include both
144:
than any of the constituent species growing separately. The algae or cyanobacteria benefit their fungal partner by producing organic carbon compounds through
244:. Overall, about 98% of lichens have an ascomycetous mycobiont. Next to the Ascomycota, the largest number of lichenized fungi occur in the unassigned
82:
appears to be a successful way for a fungus to derive essential nutrients, as about 20% of all fungal species have adopted this mode of life. The
289:, with about 40% of species forming such an association. Some of these lichenized fungi occur in orders with nonlichenized fungi that live as
511:
The alga cell is now incorporated into the lichen. It starts increasing in cell size in response. The hyphae continue growing and swelling.
803:
680:
568:
498:
The process by which the fungus and the photobioant comes together is called "lichenization". There are five steps to this process:
228:
The alga or cyanobacterium bears its own scientific name, which has no relationship to either the name of the lichen or the fungus.
165:
is the most common genus, occurring in about 20% of all lichens. The second most commonly represented green alga genus is
359:
Approximately 100 species of photosynthetic partners from 40 genera and 5 distinct classes (prokaryotic:
200:”. Cyanobacteria occur as symbionts only in about 8% of known lichens. The most commonly occurring genera of symbiotic
827:
704:
407:, but new DNA data shows many independent lines of evolution exist among this formerly large taxonomic group.
52:
420:. Taxonomic revisions have moved several photobionts outside of the genus, but mostly still within order
941:
179:
133:
873:
Most members of the order
Trebouxiales are edaphic or live in symbiosis with fungi in lichen thalli.
167:
892:
Pichler, Gregor; Muggia, Lucia; Carniel, Fabio
Candotto; Grube, Martin; Kranner, Ilse (May 2023).
356:. The layer of tissue containing the cells of the photobiont is called the “photobiontic layer”.
821:
698:
156:
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after its completion), the fungus and the alga continue to exchange different chemical signals.
723:
Rikkinen J. (1995). "What's behind the pretty colors? A study on the photobiology of lichens".
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is a combination of fungus and/or algae and/or cyanobacteria that has a very different form (
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About 20% of all fungal species are able to form lichens. The fungal partner may be an
145:
336:). Lichenized and nonlichenized fungi can even be found in the same genus or species.
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The fungus makes initial contact with the alga by growing appressoria and haustoria.
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The term 'Trebouxioid' refers to green algal photobionts similar to those in genus
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360:
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141:
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is now a relatively small order and may no longer include any lichen photobionts.
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159:). About 90% of all known lichens have a green alga as a symbiont. Among these,
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The majority of the lichens contain eukaryotic autotrophs belonging to the
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20:
Schematic cross section of lichen, a symbiosis between green algae and a
531:; They are not considered part of the lichen. These are referred to as “
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is a lichen with a cyanobacterium as its main photosynthetic component (
894:"How to build a lichen: from metabolite release to symbiotic interplay"
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476:
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Another cyanolichen group, the jelly lichens (e.g., from the genera
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The fungal structure continues differentiating into a full thallus.
117:
15:
403:, which is common in lichens. This was once placed in the order
391:
About 90% of all known lichens have a green alga as a symbiont.
657:
Lichens, an illustrated guide to the
British and Irish species
565:
Lichens of North
America Information (formerly www.lichen.com)
375:) have been found to associate with the lichen-forming fungi.
778:
Friedl, T.; BĂĽdel B. "Photobionts". In Nash III, T.H. (ed.).
614:"Introduction to Lichens – an Alliance between Kingdoms"
344:
The photosynthetic component of a lichen is called the
316:
in which all members are engaged in this habit (Orders
508:
The fungus grows hyphae to completely engulf the alga.
798:. Nash, Thomas H. Cambridge University Press. 2008.
675:. Nash, Thomas H. Cambridge University Press. 2008.
285:
The largest number of lichenized fungi occur in the
445:). Many cyanolichens are small and black, and have
639:. University of California Museum of Paleontology.
616:. University of California Museum of Paleontology.
527:Some fungi can only be found living on lichens as
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782:. Cambridge, UK: Cambridge University Press.
196:, which are often called by their old name “
659:. Slough, UK: Richmond Publishing Co. Ltd.
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597:. Australian National Botanical Garden.
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312:Other lichen fungi occur in only five
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155:(green algae) or to the Xanthophyta (
7:
848:. Alan Silverside's Lichen Glossary.
767:. Alan Silverside's Lichen Glossary.
561:"Lichen Biology and the Environment"
395:'Chlorococcoid' means a green alga (
559:Sylvia Sharnoff; Stephen Sharnoff.
252:are lichenized, but these include
14:
399:) that has single cells that are
120:that have discovered agriculture"
869:10.1016/B978-012370626-3.00132-0
571:from the original on 2023-11-09
859:Krienitz, L. (2009). "Algae".
192:The prokaryotes belong to the
63:) living among filaments of a
1:
861:Encyclopedia of Inland Waters
51:is the mutually beneficial
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101:
59:and/or blue-green algae (
340:Photosynthetic component
28:, called the cortex 2.
826:: CS1 maint: others (
703:: CS1 maint: others (
637:"Lichens: Systematics"
53:symbiotic relationship
45:
655:Dobson, F.S. (2000).
276:, such as species of
266:, such as species of
256:, such as species of
122:— Trevor Goward
24:. 1. Thick layers of
19:
863:. pp. 103–113.
248:. Comparatively few
49:Symbiosis in lichens
595:"What is a lichen?"
98:Overview of lichens
844:Silverside, Alan.
763:Silverside, Alan.
529:obligate parasites
468:(e.g., species of
449:as the substrate.
297:(for example, the
157:yellow-green algae
46:
32:3. Loosely packed
911:10.1111/nph.18780
846:"Entries 'A'-'F'"
765:"Entries 'P'-'Z'"
533:lichenolous fungi
488:Celtic Rainforest
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365:Trebouxiophyceae
274:corticioid fungi
264:clavarioid fungi
246:fungi imperfecti
232:Fungus component
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295:plant parasites
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180:Pseudotrebouxia
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795:Lichen Biology
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672:Lichen Biology
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259:Lichenomphalia
250:basidiomycetes
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146:photosynthesis
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373:Chlorophyceae
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36:4. Anchoring
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573:. Retrieved
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537:
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481:
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459:
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451:
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429:Cyanolichens
422:Trebouxiales
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369:Phaeophyceae
361:Cyanophyceae
358:
351:
345:
343:
326:Peltigerales
311:
284:
277:
269:Multiclavula
267:
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235:
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220:Nomenclature
211:
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197:
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168:Trentepohlia
166:
160:
150:
142:biochemistry
127:
111:
74:Living as a
73:
48:
47:
942:Lichenology
439:cyanolichen
397:Chlorophyta
387:Green algae
322:Gyalectales
318:Graphidales
303:Dothideales
291:saprotrophs
153:Chlorophyta
94:organisms.
88:prokaryotic
84:autotrophic
57:green algae
30:Green algae
575:2023-11-09
543:References
443:photobiont
353:phycobiont
347:photobiont
287:Ascomycota
279:Dictyonema
238:Ascomycete
138:physiology
134:morphology
92:eukaryotic
67:, forming
822:cite book
814:819628036
699:cite book
691:819628036
471:Peltigera
461:Leptogium
447:limestone
417:Trebouxia
307:Pezizales
299:Leotiales
213:Scytonema
174:Trebouxia
162:Trebouxia
936:Category
921:10952756
731:: 1–226.
569:Archived
186:Myrmecia
76:symbiont
42:rhizines
483:Degelia
477:Lobaria
466:foliose
455:Collema
401:globose
254:agarics
114:Lichens
40:called
918:
812:
802:
689:
679:
480:, and
380:thalli
332:, and
314:orders
305:, and
272:, and
207:Nostoc
140:, and
130:lichen
104:Lichen
80:lichen
69:lichen
65:fungus
38:hyphae
34:hyphae
26:hyphae
22:fungus
746:et al
744:Kirk
183:, or
118:fungi
78:in a
828:link
810:OCLC
800:ISBN
705:link
687:OCLC
677:ISBN
210:and
204:are
116:are
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Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
