Taxonomy and distribution of Thorea (Thoreaceae, Rhodophyta) in Brazil

Necchi, Orlando; Zucchi, Marcelo Ribeiro

doi:10.1127/algol_stud/84/1997/83

Cited by 12 publications

(15 citation statements)

References 5 publications

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“…The characteristics described above agreed with the general descriptions of spermatangia, carpogonia and carposporophytes for Thorea given by Yoshizaki (1986), Necchi (1987), Necchi and Zucchi (1997a), and Entwisle and Foard (1999).…”

Section: Morphological Analysissupporting

confidence: 88%

“…We included all morphological characters previously considered to be of taxonomic importance, and the microscopical analyzes followed the same procedures described by Sheath etal. (1993) and Necchi and Zucchi (1997a). To examine the frequency of secondary branches, we evaluated the branch density for the whole plant (dense vs sparse branching), and also enumerated the branches m a 30 mm length (Sheath etal.…”

Section: Methodsmentioning

confidence: 99%

“…They are elliptical or obovoidal, 10.0-25.8 |jm in length and 7.0-18.0 ^jm in diameter. The real existence of monosporangia in Thorea has been questioned {Necchi 1987; Necchi and Zucchi 1997a). as they could be spermatangia or carposporangia.…”

Section: Morphological Analysismentioning

confidence: 99%

“…Necchi (1987) described in detail the sexual reproduction in T. violacea (as Thorea bachmannii Pujals). Necchi and Zucchi (1997a) reported the occurence of T. violacea with descriptions, as well as environmental and geographical information, whereas Necchi etal. (1999) listed T. violacea from hard water regions in Sao Paulo State, including environmental data.…”

Section: Introductionmentioning

confidence: 99%

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Systematics and distribution of Thorea (Thoreaceae, Rhodophyta) from central Mexico and south-eastern Brazil

Carmona¹,

Necchi²

2001

Phycological Res

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SUMMARY Thirteen populations of Thorea were analyzed from central Mexico and south‐eastern Brazil. All populations were considered as belonging to a single species [Thorea hispida (Thore) Desvaux], with wide variation of morphological features. Secondary branches varying in frequency were observed in several populations with an overlapping in the range of branch density for Thorea violacea Bory and T hispida (0–9 and 11–41 per 30 mm, respectively). As this is the most distinguishing character and on the basis of the overlapping (within a same population or even a single plant), we regarded T. violacea as a synonym of T hispida.‘Chantransia’ stage in culture, as well as gametophyte and carposporophyte were described in detail. We confirmed tine coexistence of asexual monosporangia with sexual reproductive structures (carpogonia and spermatangia) and carposporangia. Size, content, arrangement and chromosome number were the most distinctive characteristics among spermatangia, carposporangia and monosporangia. Monosporangia can be promptly differentiated from spermatangia by their granulated content and larger size but they are similar to carposporangia in shape and size; however, monosporangia are not arranged in fascicles. Structures resembling bisporangia were observed in female plants of some populations. Chromosome numbers were n = 4 for spermatangia and fascicle cells, and 2n ca 8 for gonimoblast filaments, carpospores and the ‘Chantransia’ stage cells. The populations of Thorea from central Mexico and south‐eastern Brazil corroborated the known world distribution for T. hispida, consisting dommantly of tropical to subtropical rainforests, sometimes extending into warm temperate areas. Thorea hispida occurred in warm (temperature 17.6–28.O°C), neutral to alkaline (pH 7.0–8.0), high ion content (specific conductance 59–2140 μS cm−1), moderate flowing (current velocity 17–43 cm/s) and shallow waters (depth <50cm); these data are essentially similar to previous reports.

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Section: Morphological Analysissupporting

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Morphological Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Systematics and distribution of Thorea (Thoreaceae, Rhodophyta) from central Mexico and south-eastern Brazil

Carmona¹,

Necchi²

2001

Phycological Res

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“…Several studies have focused on the morphology, systematics, and distribution of several species of Thorea; morphological variations among natural populations were investigated (Necchi & Zucchi 1997), and on the basis of those variations, species descriptions were revised (Sheath et al 1993;Carmona & Necchi 2001), new species were erected (Entwisle & Foard 1999;Müller et al 2002), and habitat environments were investigated . There have been few reports on the life history of members of the genus Thorea (Arasaki 1937;Swale 1962;Yoshizaki 1986;Necchi 1987), and no detailed study is known on the seasonality or reproductive ecology of natural populations.…”

Section: Introductionmentioning

confidence: 99%

Somatic meiosis and development of the juvenile gametophyte in members of the Batrachospermales sensu lato (Rhodophyta)

Necchi

Jrménez

2002

Phycologia

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A. HIGA, F. KASAI, M. KAWACHI, S. KUMANO, H. SAKAYAMA, M. MIYASHITA AND M.M. WATANABE. 2007. Seasonality of gametophyte occurrence, maturation and fertilization of the freshwater red alga Thorea okadae (Thoreales, Rhodophyta) in the Kikuchi River, Japan. Phycologia 46: 160-167.We investigated the seasonality of life history stages in the freshwater red alga Thorea okadae in the Kikuchi River (Kumamoto, Japan), a broad (24-72 m wide), stony stream with marked annual variation in current velocity and discharge (10-350 m 3 s Ϫ1 ). Gametophytes were observed from early autumn (September) to late spring (April-May), and gametangial formation began in December and peaked in March. Fertilization occurred primarily in March and April, and despite a sparse distribution of gametophytes in the river, a high percentage of female gametophytes were fertilized (82%). Chantransia stages (sporophytes) persisted year-round, although their estimated percent cover on rocks in the warm season (August-September) was greater than in the cold season (January-May). The appearance of gametophytes paralleled a decrease in day length, and consequently, a decrease in total irradiance and water temperature. We suggest that these environmental conditions were proximate factors affecting phenological changes in T. okadae and that variation in river discharge (unstable and high vs stable and low) may ultimately have driven these life history patterns in this macroalga. In situ growth measurements indicated that no elongation and sometimes a length reduction occurred in gametophytes during the growing period, while rapid growth of gametophytes (65-cm increase in 43 days) was observed at the same time. These results and in situ observations suggest that the distal portions of gametophytes were frequently broken off and that many gametophytes were entirely swept away even in the growing season.

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A PROPOSAL FOR A NEW RED ALGAL ORDER, THE THOREALES¹

Müller

Sherwood

Pueschel

et al. 2002

Journal of Phycology

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Representatives of the freshwater red algal familyThoreaceae were studied to resolve their taxonomic and phylogenetic status. Three specimens of Nemalionopsis and five collections of Thorea were examined for pit plug ultrastructure and analyzed for the sequences of the genes coding for the large subunit of RUBISCO ( rbc L) and the small subunit of rRNA (18S rRNA). The phylogenetic trees generated from the two genes, and a combined tree all showed the Thoreaceae to be contained in a well-supported monophyletic clade that is separate from the other two families currently classified in the Batrachospermales, the Batrachospermaceae and the Lemaneaceae. In addition, secondary structure elements of the 18S rRNA gene were observed at positions 650 and 1145 ( Escherichia coli numbering system) that are not present in other members of the Rhodophyta. The pit plugs of the gametophytic and chantransia stages of the Thoreaceae contain two cap layers, the outer one of which is typically plate-like, though occasionally inflated ones have been seen. No pit plug cap membrane has been observed. These findings indicate the Thoreaceae has been misclassified in the Batrachospermales and should be placed in its own order, the Thoreales. This order is characterized by having freshwater representatives with multiaxial gametophytes, a uniaxial chantransia stage, and pit plugs with two cap layers, the outer one of which is usually plate-like.

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Taxonomy and distribution of Thorea (Thoreaceae, Rhodophyta) in Brazil

Cited by 12 publications

References 5 publications

Systematics and distribution of Thorea (Thoreaceae, Rhodophyta) from central Mexico and south-eastern Brazil

Systematics and distribution of Thorea (Thoreaceae, Rhodophyta) from central Mexico and south-eastern Brazil

Somatic meiosis and development of the juvenile gametophyte in members of the Batrachospermales sensu lato (Rhodophyta)

A PROPOSAL FOR A NEW RED ALGAL ORDER, THE THOREALES¹

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Taxonomy and distribution of Thorea (Thoreaceae, Rhodophyta) in Brazil

Cited by 12 publications

References 5 publications

Systematics and distribution of Thorea (Thoreaceae, Rhodophyta) from central Mexico and south-eastern Brazil

Systematics and distribution of Thorea (Thoreaceae, Rhodophyta) from central Mexico and south-eastern Brazil

Somatic meiosis and development of the juvenile gametophyte in members of the Batrachospermales sensu lato (Rhodophyta)

A PROPOSAL FOR A NEW RED ALGAL ORDER, THE THOREALES1

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A PROPOSAL FOR A NEW RED ALGAL ORDER, THE THOREALES¹