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Name derivation:
Porphyra= Gr. porphyra: a purple dye umbilicalis= L. umbilicatus: navel like or a central stalk
Classification:
Porphyra C. Agardh 1824; 60 of 268 species descriptions are currently accepted taxonomically (Guiry and Guiry 2014). Order Bangiales; Family Bangiaceae
Morphology:
The foliose blades or gametophytes are red-brown, brown, grey-brown, or olive green, or brown-purple when dried, and also shiny when dry on the intertidal rocks. Blades are attached by a minute, tough, holdfast. Blades are usually round, sometimes elongate, with a slight to extreme cordate base that overlaps and appears peltate, 1 (monostromatic) or 2 (distromatic) cells thick, and rubbery or elastic. Margins are flat to slightly ruffled. Algae are monoecious or dioecious, with marginal sori; neutral sporangia may also occur. Spermatangia are in packets of 4 by 4 in surface view and 8 by 8 in transverse section (e.g. 128 spermatia). Zygotosporangia are in packets of 2 x 4 in surface view and 2 x 2 in transverse section (e.g. 16 zygotospores) (Dawes and Mathieson 2008). “Conchocelis rosea” is the sporophytic stage of Porphyra spp. It grows within shells and forms rounded red spots that are often confluent.
Similar genera:
Similar genera: Bangia, Chroodactylon, Erythrocladia, Erythrotrichia, Porphyropsis, Porphyrostromium, and Stylonema
Chloroplast genes:
Extensive DNA sequencing of the chloroplast genome of the red alga Porphyra purpurea has resulted in the detection of more than 125 genes. Fifty-eight (approximately 46%) of these genes are not found on the chloroplast genomes of land plants. These include genes encoding 17 photosynthetic proteins, three tRNAs, and nine ribosomal proteins. In addition, nine genes encoding proteins related to biosynthetic functions, six genes encoding proteins involved in gene expression, and at least five genes encoding miscellaneous proteins are among those not known to be located on land plant chloroplast genomes (Reith 1993).
Antioxidant activity:
Sulfated polysaccharide fraction F2 from Porphyra haitanesis (Rhodophyta) showed inhibitory effect on the in vitro lipid peroxidation. In the present study, the age-related changes in the antioxidant enzyme activity, lipid peroxidation, and total antioxidant capacity (TAOC) in different organs in mice were investigated and the in vivo antioxidant effect of F2 in aging mice was checked (Zhang 2003).
Integrated aquaculture:
For rapid growth and appropriate pigmentation,Porphyra requires the constant availability of nutrients, especially in summer when temperate waters are generally nutrient depleted. Cultivation near salmon cages allows the alleviation of this seasonal depletion by using the significant loading of fish arms, which is then valued (wastes become fertilisers) and managed (competition for nutrients between desirable algal crops and problem species associated with severe disturbances). Porphyra, being an extremely efficient nutrient pump, is an excellent candidate for integrated aquaculture for bioremediation and economic diversification (Mathieson etal 1999).
Habitat:
Common; an aseasonal annual, growing on rocks and pilings on the upper (spray zone) intertidal to the low tide mark on exposed coasts and within in estuaries; often heavily epiphytized in late summer.
References:
Agardh, C.A. (1824). Systema Algarum. pp. [i]-xxxvii, [1]-312. Lundae [Lund]: Literis Berlingianis [Berling]. Brodie, J. and L. M. Irvine. 2003. Seaweeds of the British Isles, Vol. 1. Rhodophyta, Part 3B. Bangiophycidae. xiii + 167 pp., 54 figs., 6 tables Dawes, C.J. and A.C. Mathieson 2008. Seaweeds of Florida. University Press of Florida (592 pp). Guiry, M.D. and G.M. Guiry 2013. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 07 May 2013. Mathieson, Arthur. Developing Porphyra/salmon integrated aquaculture for bioremediation and diversification of the aquaculture industry." Journal of Applied Phycology Vol. 11.No. 5: 463.472. Reith, M., and J. Munholland. "A high-resolution gene map of the chloroplast genome of the red alga Porphyra purpurea." The Plant Cell Vol. 5.No. 4 465-475. Taylor, W. R. 1957. Marine Algae of the Northeastern Coast of North America. Revised edition. Univ. Michigan Press., Ann Arbor, ix + 509 pp. Zhang, Q. 2003. In Vivo Antioxidant Activity of Polysaccharide Fraction from Porphyra Haitanesis (Rhodophyta) in Aging Mice. Pharmacological research 48(2):151–155.