• ALGAE
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• v.26 no.2
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• pp.193-200
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• 2011

The stress tolerance ability of Pelvetia canaliculata (L.) Dcne. Et Thur. and Fucus spiralis L. to temporary and periodic emersion stress was examined in order to test the following hypotheses: The upper shore alga, P. canaliculata is more tolerant to desiccation than F. spiralis in the germling stage and the former outgrows the latter under desiccation stress; Germling stress tolerance of the two species is age-specific; Crowding of germlings protects them from desiccation, irrespective of the species involved. Germling growth of the two species was retarded with increasing exposure period and was age-specific, as they were air-exposed at an earlier stage. After 16 days, the length of Pelvetia germlings was similar between 2-day-old germlings (125-140 ${\mu}m$) and 7-day-old germlings (134-140 ${\mu}m$), which were air-exposed during the same period (0, 6, 12, 24, 48, and 72 h) at the two different ages. However, Fucus germlings were significantly larger at 7-day-old germlings (211-277 ${\mu}m$) than at 2-day-old germlings (184-278 ${\mu}m$), especially in the treatments of 48 and 72 h. These results indicate that Fuscus grow faster than Pelvetia and that the growth response of germlings to temporary emersion stress is more sensitive in Fucus than that in Pelvetia. Growth of germlings of both species was reduced with increasing density under favorable growth conditions (submerged control and 6 h / 12 h exposure treatments) in the periodic air-exposed experiments using tidal tanks, but was enhanced under severe emersion stress conditions. P. canaliculata showed better growth at 6 h exposure treatment than that of the control, under continuous submergence, indicating that Pelvetia germlings require a periodic exposure period. Fucus germlings always grew faster than those of Pelvetia and did best in mixed cultures, whereas Pelvetia did least well when mixed with Fucus germlings. The adverse effects of F. spiralis on P. canaliculata were greater than those of Pelvetia cohorts. The outcome of interspecific competition between F. spiralis and P. canaliculata gemlings was slightly altered by exposure period but not to such an extent as to change the outcome.

• Journal of Life Science
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• v.19 no.3
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• pp.311-316
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• 2009

The brown algae, or phaeophytes, are a large group of multicellular algae, including many notable types of seaweed. We analysed intra- and interspecific phylogenic studies within the genus Pelvetia in Korea and compared them with results of both same and different species in GenBank. The sequences for P. babingtonii in Korea were generally similar to those for P. babingtonii AF102957, and the sequences of P. siliquosa in Korea were also similar to those of P. siliquosa AF102958. Sequence variation within the Pelvetia is mostly due to nucleotide substitutions, although several small indels and some large indels can be found. Another source of sequence divergence is length variation due to stretches of short repeats that occur at the ITS1 or ITS2 in all the Pelvetia. NJ analysis consists mainly of two clades. One of them contains P. canaliculata and P. limitata, and is sister to the rest of the genus (P. siliquosa, P. compressa, and P. babingtonii). P. babingtonii is not grouped one clade. In the MP analysis, ten accessions or populations were fully resolved and all accessions from the same species formed with 99% or 100% bootstrap supports.