Life history and morphological studies of Punctaria tenuissima (Chordariaceae, Phaeophyceae), a new record for the Azores

Parente, M.I. and Fletcher, R.L. and Neto, A.I. and Tittley, I. and Sousa, A.F. and Draisma, S. and Gabriel, D. (2010) Life history and morphological studies of Punctaria tenuissima (Chordariaceae, Phaeophyceae), a new record for the Azores. Botanica Marina, 53 (3). pp. 223-231.

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Punctaria tenuissima (Chordariaceae, Phaeophyceae) is reported for the first time from the Azores. Erect thalli were collected on the Island of Sao Miguel; they were up to 3 cm long, flattened and often twisted. The plurilocular sporangia were formed from surface cells that were quadrate or rectangular in surface view. Unilocular sporangia were not observed in the field. In culture, the plurispores of P. tenuissima developed into Hecatonema-like, tufted, prostrate thalli that formed plurilocular sporangia. The plurispores of the prostrate thalli cultured at 15 degrees C with a long day (LD) photoperiod developed into new prostrate thalli, which in turn formed plurilocular sporangia. This cycle was repeated 5 times, resulting in several generations of reproductive prostrate thalli. When these cultures were cooled to 10 degrees C with a short day (SD) photoperiod, new erect thalli developed from the prostrate thalli resembling the thalli collected in the field. These erect blades produced unilocular and plurilocular sporangia on the same or on different thalli. The plurispores and unispores produced by the erect thalli at 10 degrees C under SD conditions once again developed into new prostrate thalli. This is the first report of unilocular sporangia formed in cultures of P. tenuissima. Sexual reproduction was not observed. The culture conditions, particularly temperature and daylength, appeared to influence the formation of erect blades. The Punctaria-like thalli were produced in 10 degrees C/SD conditions, whilst the Hecatonema-like thalli were produced under 10 degrees-15 degrees C/LD and SD conditions. These results are similar to those reported for P. tenuissima from other locations and suggest the occurrence of both direct and heteromorphic life histories in the Azorean algae.

Item Type: Article
Uncontrolled Keywords: Hecatonema terminale; life history; morphology; Phaeophyceae; Punctaria tenuissima
Subjects: R Medicine
Depositing User: Mr Faizal 2
Date Deposited: 20 Apr 2015 02:42
Last Modified: 20 Apr 2015 02:42

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