| 词条 | Hildenbrandia |
| 释义 |
| taxon = Hildenbrandia | image = Hildenbrandia crouaniorum 008.JPG | image_caption = The darker red alga encrusting this rock fragment is H. crouaniorum | image2 = Hildenbrandia rivularis gemma SEM.jpg | image2_caption = SEM of a H. rivularis gemma. Scale bar: 50 μm | authority = Nardo, 1834 }} Hildenbrandia is a genus of thalloid red alga comprising 26 species. The slow-growing, non-mineralized thalli take a crustose form.[1] Hildenbrandia reproduces by means of conceptacles and produces tetraspores. MorphologyHildenbrandia cells are around 3–5 μm in diameter and the filaments are around 50–75 μm in height.[2]The thallus comprises two layers; the hypothallus, which attaches to the rock, and the perithallus, a pseudoparenchymous layer comprising vertical filaments, which unlike coralline red algae is not further differentiated.[3][4] GrowthHildenbrandia comprises orderly layers of vertical oblong cells with thick vegetative cell walls, occasionally connected by secondary pit connections with pit plugs in the septal pores.[5] It grows at its margins, away from the centre, and is able to quickly repair any gaps arising by regenerating from a basal layer of cells.[6] As plants become more mature, they become multi-layered and strongly pigmented near their centres, whilst their single-layered margins begin to grow more slowly.[6] Multi-layered areas may develop in the margins; these will detach and float away as gemmae to form new colonies, leaving a single layer of cells beneath them once they separate from the host plant.[6]Newly settled gemmae form rhizoids.[6] Conceptacles develop in a haphazard manner; cells in conceptacle regions deform one another and become less regularly shaped as they grow larger.[5] In a similar fashion to the coralline algae, the outer layer of the thallus is shed seasonally, presumably to avoid colonization by epiphytes.[7] HabitatThe freshwater species H. rivularis[6] and H. angularis[6] seems to form a clade,[8] and require an alkaline pH and hard water, preferring clean water.[9] Unlike most other freshwater red algae (which prefer running water), H. rivularis prefers still water, particularly shady lakes or ponds.[9] H. rubra and other marine species are found in brackish waters, but freshwater / gemma-bearing species cannot tolerate even moderate salinities.[10] The genus is often found in a symbiotic partnership with fungi.[11] Hildenbrandia has a remarkable tolerance to stresses including extreme temperatures, desiccation, and Ultra-violet light; it can be up and photosynthesizing near full capacity just minutes after being cooled to −17 °C or subjected to extreme salinities.[12]ReproductionSexual reproduction has never been observed in any Hildenbrandia species.[10] It can reproduce by splitting into multiple colonies by fragmentation, or via stolons (i.e. sending out lateral branches) or gemmae.[13] Marine Hildenbrandia, on the other hand, reproduce by means of tetraspores that are produced within the thallus by conceptacles.[6] SystematicsThe genus contains these species[14] (this list is out of date):
StonehengeThe presence of H. rivularis near Stonehenge has been put forward as a reason for the site's perceived mystical properties. Flint in pools near the henge takes on a pink hue a couple of hours after being taken out of water due to the presence of the algae. It is assumed that ancient hunter-gatherers would have seen the rocks as having magical properties and would have deemed the site worthy of interest.[15] [16][17]References1. ^{{Cite journal| last1 = Dethier | first1 = M.| title = The ecology of intertidal algal crusts: variation within a functional group| journal = Journal of Experimental Marine Biology and Ecology| volume = 177| pages = 37–71| year = 1994| doi = 10.1016/0022-0981(94)90143-0}} 2. ^{{Cite journal | last1 = Sherwood | first1 = A. | last2 = Sheath | first2 = R. | title = Biogeography and systematics of Hildenbrandia (Rhodophyta, Hildenbrandiales) in Europe: inferences from morphometrics and rbcL and 18S rRNA gene sequence analyses | journal = European Journal of Phycology | volume = 35 | pages = 143 | year = 2000 | doi = 10.1080/09670260010001735731}} 3. ^{{cite web | url = http://depts.washington.edu/fhl/mb/Hildenbrandia_Ben/morphology.html | title = Hildenbrandia Ben: Morphology | publisher = washington.edu}} 4. ^{{cite journal | author = Cabioch, J. | author2 = Giraud, G. | year = 1982 | title = La structure hildenbrandioïde, stratégie adaptative chez les Florideés | language = French | journal = Phycologia | volume = 21 | issue = 3 | pages = 308–315 | doi=10.2216/i0031-8884-21-3-307.1}} 5. ^1 {{Cite journal| last1 = Pueschel | first1 = C.| title = Ultrastructural observations of tetrasporangia and conceptacles in Hildenbrandia (Rhodophyta: Hildenbrandiales)| journal = European Journal of Phycology| volume = 17| issue = 3| pages = 333–341| year = 1982| doi = 10.1080/00071618200650331}} 6. ^1 2 {{Cite journal| last1 = Sherwood | first1 = A. R.| last2 = Sheath | first2 = R. G.| title = Microscopic analysis and seasonality of gemma production in the freshwater red alga Hildenbrandia angolensis (Hildenbrandiales, Rhodophyta)| journal = Phycological Research| volume = 48| pages = 241| year = 2000| doi = 10.1046/j.1440-1835.2000.00208.x}} 7. ^{{Cite journal | doi = 10.1080/00071618800650021 | title = Cell sloughing and chloroplast inclusions in Hildenbrandia rubra (Rhodophyta, Hildenbrandiales) | year = 1988 | last1 = Pueschel | first1 = C. | journal = European Journal of Phycology | volume = 23 | pages = 17–23 }} 8. ^{{Cite journal| last1 = Sherwood | first1 = A. R.| last2 = Sheath | first2 = R. G.| title = Systematics of the Hildenbrandiales (Rhodophyta): Gene Sequence and Morphometric Analyses of Global Collections| journal = Journal of Phycology| volume = 39| pages = 409–422| year = 2003| doi = 10.1046/j.1529-8817.2003.01050.x}} 9. ^1 {{Cite journal| url = http://www.oandhs.org/files/60.pdf| journal = International Journal of Oceanography and Hydrobiology | volume= XXXIII| issue=1 | ISSN = 1730-413X | pages = 47–54| year = 2004 | title = Indicator value of freshwater red algae in running waters for water quality assessment| author1 = Eloranta, P.| author2 = Kwandrans, J.}} 10. ^1 {{Cite journal| last1 = Sherwood | first1 = A. R.| last2 = Shea | first2 = T. B.| last3 = Sheath | first3 = R. G.| title = European freshwater Hildenbrandia (Hildenbrandiales, Rhodophyta) has not been derived from multiple invasions from marine habitats| journal = Phycologia| volume = 41| pages = 87| year = 2002| doi = 10.2216/i0031-8884-41-1-87.1}} 11. ^{{Cite journal| last1 = Saunders | first1 = G. W.| last2 = Bailey | first2 = J. C.| title = Molecular Systematic Analyses Indicate That the Enigmatic Apophlaea is a Member of the Hildenbrandiales (Rhodophyta, Florideophycidae)| journal = Journal of Phycology| volume = 35| pages = 171| year = 1999| doi = 10.1046/j.1529-8817.1999.3510171.x}} 12. ^{{Cite book| last1 = Garbary | first1 = D. | chapter = The Margin of the Sea| pages= 173–191| year = 2007 | doi = 10.1007/978-1-4020-6112-7_9| title = ALGAE AND CYANOBACTERIA IN EXTREME ENVIRONMENTS| series = Cellular Origin, Life in Extreme Habitats and Astrobiology| volume = 11| issue= 3}} 13. ^1 2 3 4 {{Cite journal | last1 = Wayne Nichols | first1 = H. | title = Culture and Development of Hildenbrandia rivularis from Denmark and North America | journal = American Journal of Botany | volume = 52 | issue = 1 | pages = 9–15 | year = 1965 | doi = 10.2307/2439969}} 14. ^{{cite web|last=Guiry|first=M.D.|last2=Guiry|first2=G.M.|year=2008|title=Hildenbrandia|work=AlgaeBase|publisher=World-wide electronic publication, National University of Ireland, Galway|url=http://www.algaebase.org/search/genus/detail/?genus_id=22|accessdate= 2009-04-18}} 15. ^{{cite web | url=http://www.dailymail.co.uk/sciencetech/article-2624129/Stonehenge-LONDON-Mesolithic-River-Avon-acted-like-A-Road-ancient-log-boats-expert-claims.html | title=Stonehenge was the 'LONDON of the Mesolithic': River Avon acted like an 'A-Road' for ancient log boats, expert claims}} 16. ^{{cite web|url=http://www.silversaffron.co.uk/wp-content/uploads/2014/07/02_Jacques_VespasiansCamp.pdf|title=Mesolithic settlement near Stonehenge: excavations at Blick Mead, Vespasian’s Camp, Amesbury|website=www.silversaffron.co.uk|format=pdf}} 17. ^{{cite journal|last1=Jacques|first1=David|title=Mesolithic settlement near Stonehenge: excavations at Blick Mead, Vespasian’s Camp, Amesbury|journal=Wiltshire Archaeological and Natural History Magazine|date=2014|volume=107 |pages=7–27}} External links{{Commons category}}
1 : Red algae genera |
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