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Porphyra is a It is a foliose red algal genus of about 70 species.[1] It lives in the intertidal, typically between the upper intertidal to the splash zone. It is used to make nori, the most commonly eaten seaweed.
[edit] Life cycle
It displays a heteromorphic alternation of generations. The thallus we see is the haploid generation, it can reproduce asexually by forming spores which grow to replicate the original thallus. It can also reproduce sexually. Both male and female gametes are formed on the one thallus. The female gametes while still on the thallus are fertilized by the released male gametes, which are non-motile. The fertilised, now diploid, carposporangia produce spores (carpospores) which settle, they bore into shells, germinate and form a filamentous stage which was originally thought to be a different species of alga, and was referred to as Conchocelis rosea. It is now known to be the diploid stage of Porphyra. After reduction division (meiosis) spores are produced, released and when they settel in a suitable site grow to become the plant which we know as Porphyra. [1][2]
Most human cultures with access to Porphyra use it as a food or somehow in the diet, it is probably the most domesticated of the marine algae. [3] The marine red alga Porphyra, which is called Nori in Japanese, has been cultivated extersively in many oriental countries as an edible seaweed used to wrap the rice and fish that compose the Japanese food sushi. In Japan, the annual production of Porphyra spp. is valued at 100 billion yen (US$ 1 billion).[4]
[edit] References
- ^ a b Brodie, J.A. and Irvine, L.M. 2003. Seaweeds of the British Isles. Volume 1 Part 3b. The Natural History Museum, London.ISBN 1 898298 87 4
- ^ Thomas, D. 2002. Seaweeds. The Natural History Museum, London. ISBN 0 565 09175 1
- ^ Mumford, T.F. and Miura, A. 4.Porphyra as food: cultivation and economics. in Lembi, C.A. and Waaland, J.R. 1988. Algae and Human Affairs. Cambridge University Press, Cambridge. ISBN 0-521-32115-8
- ^ Aoki, Y. and Kamei, Y. 2006 Preparation of recombinant polysaccharide-degrading enzymes from the marine bacterium, Pseudomonas sp. ND137 for the production of protoplasts of Porphyra yezoensis Eur. J. Phycol. 41: 321 - 328
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