Rhodochorton

Taxobox
name = "Rhodochorton"
domain = Eukaryota
regnum = Plantae
subkingdom = Biliphyta
phylum = Rhodophyta
subphylum = Rhodophytina
classis = Florideophyceae
ordo = Acrochaetiales
familia = Acrochaetiaceae
genus = "Rhodochorton"
genus_authority=Nägeli [Dixon, 1982:64]
subdivision_ranks=Species
subdivision=Species include:
*"R. entozoicum" (Reinsch) De Toni
*"R. kurilense" Nagai
*"R. lepadicola" (Welwitsch) De Toni
*"R. mesocarpum"
*"R. parkeri" Gibson
*"R. subsimplex" (Harvey ex Agardh) De Toni

"Rhodochorton" is a genus of filamentous red alga adapted to low light levels. It may form tufts or a thin purple "turf" up to 5 millimetres high. The filaments branch infrequently, usually at the tips.Citation
author = Fritsch, F. E.
year = 1945
title = The structure and reproduction of the algae
isbn = 0521050421
publisher = Cambridge Univ. Press
location = Cambridge
oclc = 223742770]

Morphology

In most species of "Rhodochorton", the spore does not persist in the mature plant; instead, a basal web of filaments acts as a holdfast. Indeed, all "Rhodochorton" species have distinct basal threads, usually forming a disc, and upright threads, which are typically thinner. Lateral branches usually occur at or near the top of the patent cell, and branching is concentrated towards the tips of threads.

Ecology

The organism may encrust bare rock surfaces, or be parasitic upon frondose algae - particularly "Laminaria hyperborea". [http://www.horta.uac.pt/Species/Algae/Rhodochorton_purpureum/Rhodochorton_purpureum.htm] It typically grows in the shadow of these larger algae, in the intertidal zone,citation
author = Breeman, A. M.; Hoeksema, B. W.
year = 1987
title = Vegetative propagation of the red alga "Rhodochorton purpureum" by means of fragments that escape digestion by herbivores
journal = Mar. Ecol. Prog. Ser.
volume = 35
pages = 197–201
doi = 10.3354/meps035197
url = http://www.int-res.com/articles/meps/35/m035p197.pdf] and its adaption to low light levels means it is also common in caves.It reproduces in winter using tetrasporangia and don't bear any monosporangia. [cite journal|doi=10.1111/j.1529-8817.1969.tb02569.x|title=The Life Histories Of Rhodochorton Purpureum And R. Tenue In Culture|year=1969|author=West, John A.|journal=Journal of Phycology|volume=5|pages=12] "Rhodochorton" is typically marine, but "R. investiens" dwells in fresh water.citation
author = Swale, E. M. F.; Belcher, J. H.
title = Morphological Observations on Wild and CulturedMaterial of "Rhodochorton investiens "(Lenormand)nov. comb. ("Balbiania investiens" (Lenorm.) Sirodot)
year = 1963
journal = Annals of Botany
volume = 27
issue = 2
pages = 282–290
url = http://aob.oxfordjournals.org/cgi/content/abstract/27/2/282
publisher = Annals Botany Co] Sexual reproduction has never been observed. [cite journal|doi=10.1111/j.0022-3646.1970.00368.x|title=A Monoecious Isolate Of "Rhodochorton purpureum"|year=1970|author=West, John A.|journal=Journal of Phycology|volume=6|pages=368]

It suffers predation pressure from gastropods and amphipods, but amazingly fragments of the algae are able to pass through the predators' digestive tracts alive - predation may actually form a mode of dispersal for the organism.

Life history

"Rhodochorton investiens" displays a relatively simple life cycle for a red alga.citation|author=Lee, R.E.|title=Phycology, 4th edition|year=2008|isbn= 978-0521638838|publisher= Cambridge University Press]

In the Carposporophyte: a spermatium merges with a trichogyne (a long hair on the female sexual organ), which then divides to form carposporangia - which produce carpospores.

Carpospores germinate into gametophytes, which produce sporophytes. Both of these are very similar; they produce monospores from monosporangia "just below a cross wall in a filament"and their spores are "liberated through apex of sporangial cell."

The spores of a sporophyte produce either tetrasporophytes. Monospores produced by this phase germinate immediately, with no resting phase, to form an identical copy of parent. Tetrasporophytes may also produce a carpospore, which germinates to form another tetrasporophyte.Verify source|date=August 2008

The gametophyte may replicate using monospores, but produces sperm in spermatangia, and "eggs"(?) in carpogonium.

ee also

The following species closely resemble "Rhodochorton": "Rhodothamniella "

References