See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/271076653 1986 de Paula & West Phycologia Data · January 2015 CITATIONS READS 0 32 2 authors, including: John A. West University of Melbourne 278 PUBLICATIONS 5,615 CITATIONS SEE PROFILE Some of the authors of this publication are also working on these related projects: Revision of the genera Sirodotia and Batrachospermum (Rhodophyta, Batrachospermales): sections Acarposporophytum, Aristata, Macrospora, Setacea, Turfosa and Virescentia View project Taxonomy and phylogeny of freshwater red algae View project All content following this page was uploaded by John A. West on 19 January 2015. The user has requested enhancement of the downloaded file. Phycologia (1986) Volume 25 (4), 482-493 Culture studies on Pedobesia ryukyuensis (Derbesiales, Chlorophyta), a new record in Brazil EDISON J. DE PAULA' AND JOHN A. WEST2 , Departamento de Botdnica et Centro de Biologia Marinha, Universidade de Siio Paulo, Caixa Postal 11461, Siio Paulo. SP, Brazil 2 Department of Botany, University of California, Berkeley, California 94720, USA E.J. DE PAULAAND J.A. WEST. 1986. Culture studies on Pedobesia ryukyuensis (Derbesiales, Chlorophyta), a new record in Brazil. Phycologia 25: 482-493. Pedobesia ryukyuensiswas collected in 1982 and 1983 from the Centro de Biologia Marinha (CEBIMAR), Sao Sebastiao, SP, Brazil and placed in unialgal culture. These isolates exhibit a direct sporophytic recycling life history typical of Pedobesia with three developmental stages: an encrusting calcified basal disc; branched rugose filaments arising from the base; and smooth filaments bearing sporangia. Comparisons of the Brazilian material with the known species of Pedobesia revealed the greatest morphological affinity with P. ryukyuensis(yamada et Tanaka) Kobara & Chihara and P. feldmannii Abelard, but difficulties in distinguishing the two entities are discussed. Although the life history is considered as a direct sporophytic type, specialized intracellular meiotic and gametic events may exist. INTRODUCTION Codomier (1974) and Feldmann et al (1975) de­ scribed the morphology, fine structure and cell The genus Pedobesia was established by MacRaild wall chemistry of Pedobesia lamourouxii (J. & Womersley (1974) based on culture studies of Agardh) Feldmann from the Mediterranean. In Derbesia clavaeformis (J. Agardh) De Toni iso­ 1982 Abelard described a new species, P. feld­ lated in Australia. Pedobesia differs from Der­ mannii Abelard, from the Galapagos Islands. besia and Bryopsidellain two major ways: Chihara & Kobara (1982) and Kobara & Chihara (1) Life history: Pedobesia has a direct spo­ (1981, 1984) have also investigated the culture rophytic recycling, whereas Derbesia and and taxonomy of P. lamourouxii and P. ryu­ Bryopsidellaspecies usually exhibit a hetero­ kyuensis (Yamada & Tanaka) Kobara & Chihara morphic life history with the diploid sporo­ in Japan. Womersley (1981) and Hawkes (1983) phyte as a branched filamentous stage, bearing deal with the occurrence of P. clavaeformis (J. sporangia that produce stephanokont meio­ Agardh) MacRaild & Womersley in New Zea­ zoospores, and the gametophyte as vesicular land. coenocyte (Halicystis) or a plumose branched Pedobesia is not known with assurance in the phase (Bryopsidella).However, some Derbesia western Atlantic and the first author's initial dis­ marina isolates (Kornmann 1966, 1970; Sears covery of plants in the aquarium at the Centro & Wilce 1970) also exhibit direct sporophytic de Biologia Marinha (CEBIMAR) da Universi­ recycling. For a complete discussion see Tan­ dade de Sao Paulo, and later in the field at Praia ner (1981). do Segredo, Sao Sebastiao, in the State of Sao (2) Morphology: Pedobesia has a unique dis­ Paulo in Brazil, resulted in the present paper. coid basal system with cell walls composed partially of calcium carbonate (aragonite) from which an intermediate non-calcified filamen­ MATERIALS AND METHODS tous stage arises before the upright, sporangia­ bearing filaments are produced. The first specimens were obtained as fragments Since 1974 there has been a sharp assurgency of the basal disc from an aquarium at CEBIMAR of interest in this distinctive genus. Feldmann & in early April 1982. These were cultured in 125 482 de Paula and West: Culture studies on Pedobesia 483 ml Erlenmeyer flasks with unenriched sterile sea­ cause of overgrowth by adjacent discs. These water, 20DC 16: 8 h light-dark (LD) cycle and ca. plants died in an aquarium accident in December 10-1 5/Lmol m-2 S-1 daylight fluorescent lighting. 1982, but other discs were observed in another With fortnightly changes of the medium, upright aquarium in April 1983. rugose filaments 5-10 mm long were formed in In late April and early May 1983, living plants 2 months. were obtained in the lower intertidal zone of the Apices were excised to obtain unialgal cultures exposed shore at Praia do Segredo. This locality but the coccolithophorid Ochrosphaera sp. was is characterized by intense grazing by the sea a serious contaminant tending to overgrow Pe­ urchin Echinometra lucunter and molluscs, Ac­ dobesia. In June 1982, isolation efforts were maea subrugosa Orbigny and Astrea olfersii Phi­ continued using Provasoli's ES medium-PES lippi, resulting in poor algal growth except for (McLachlan 1973) diluted to Yto strength (2 mliL Paragoniolithon solubile (Foslie & Howe in Howe) sterile seawater) in 2.0 x 4.5 cm Petri dishes, 20- Adey, Townsend & Boykins. Pedobesia is re­ 40 /Lmol m-2 S-1 daylight fluorescent illumina­ stricted to crevices, Acmaea shells and shells of tion, 12: 12 LD at 23DC. Unialgal cultures were dead Balanus. In most instances it grows as small obtained only in experiments where diatoms and (5-8 mm), irregular discs over Paragoniolithon a filamentous tuft of Pedobesia were inoculated and is commonly associated with Derbesia sp., in Erlenmeyer flasks with bubbling aeration in Halicystis sp. and Bryopsis pennata Lamouroux. 125 ml of Yto PES medium. The diatoms ap­ The discs were seen only after careful examina­ parently outcompeted the other contaminant tion of the shells under the stereoscopic micro­ Ochrosphaera. After 1 week, apices were excised scope. No adult sporangium-bearing thalli were and transferred to a fresh culture medium with found in the field despite a bimonthly survey of Ge0 (1 mg/L) to eliminate the diatoms, thus the area. 2 producing a unialgal culture of Pedobesia. Unialgal cultures used for the life history stud­ Culture studies ies were maintained in 4.5 x 2.0 cm Petri dishes, 10-20 and 30-45/Lmol m-2 S-I, 16: 8 LD at 20- Although various conditions were tested, the 25DC, with weekly to biweekly changes of the complete life history was observed only under culture medium (PES, 1";0 to 'h strength). 10-20 and 30-45 /Lmol m-2 S-1 daylight flu­ Adult sporangium-bearing filaments were pro­ orescent illumination, 20-25DC, 16: 8 LD. Both duced 15-30 days after PES enrichment was in­ basal discs and rugose filaments (Fig. 1) grew in creased from Yto to 'h strength. When apical seg­ all conditions tested, but the discs were initiated ments were excised and returned to 1";0 strength at higher PFD (30-45 /Lmol m-2 S-I) and the enrichment PES medium and low photon flux filaments were initiated at low PFD (l0-20 /Lmol density (PFD), 10-20 /Lmol m -2 s-', they con­ m-2 S-I). Conversion from the discoid to the tinued to grow without sporangium formation. filamentous habit was induced by reversing the However, segments returned to higher PFD (30- culture conditions. 45 /Lmol m-2 S-I), '/4 to 'h strength enrichment Apices of these filaments were used as inoc­ medium, continued to grow vegetatively, and also ulum and in low PFD they continued to grow formed sporangia again in 2-7 days. and branch irregularly in all directions. Those growing upward were more uniform in shape than those growing downward. The growth of these filaments was slow, only a few millimetres per RESULTS month. When transferred to higher PFD they showed a sharp negative phototropism growing General and field observations downward and attaching to the substrate. The In April 1982, numerous green crustose discs calcified basal discs developed from these at­ (20-30 mm diam.) of Pedobesia were seen at­ tached apices (Fig. 1). tached to the glass wall and the white PVC tubing Upon initial contact, filament apices became in a display aquarium at CEBIMAR. The con­ more tortuous and produced a digitate process. figuration of these discs was semicircular to ir­ Whenever one process contacted another, cir­ regular, possibly because of grazing by the sea cular to ovoid pores developed between them. urchin Echinometra lucunter Linnaeus or be- No septation occurred and the disc protoplast 484 Phyc% gia,Vol. 25 (4), 1986 lOOIJM ; -- 4 Figs 1-6. Pedobesia ryukyuensis. Fig. 1. Rugose branched filaments and discs. Fig. 2. Young fan-shaped disc. Fig. 3. Discs showing lines of growth, lines of regrowth and radial lines. Fig. 4. Individual disc showing new young discs that overgrow the older parts. Fig. 5. Portion of disc showing the pores. Fig. 6. Portion of disc showing the pores and elevated translucent patches (pillars) near the pore. was continuous with that of the filaments. Con­ and later became semicircular in outline (Figs 3, tinued growth produced a fiat, prostrate, perfo­ 14). rate stage that was initially fan-shaped (Fig. 2) Periodic changes of the culture medium may de Paula and West: Culture studies on Pedobesia 485 have resulted in the concentric growth lines in (Fig. 8) they were rare and appeared singly on the discs (Fig. 3). Marginal growth of the disc the unbranched erect siphon. However, sporan­ was either uniform or variable, resulting in con­ gial development varies a great deal. A reduction vex segments that contacted adjacent segments series of the sporangial development is shown in forming radial lines between them (Fig. 3).