Summary: Cystoseira tamariscifolia thalli collected from rocky shores and rockpools in winter and summer in Southern Spain were incubated for 7 days in UV transparent cylindrical vessels under outdoor conditions. Photosynthetic activity estimated as in vivo chlorophyll a fluorescence of photosystem II, photosynthetic pigments, antioxidant activity (DPPH assay), phenolic compounds and total internal C and N contents were determined after short-term (3 d) and mid-term (7 d) periods. Maximum quantum yield of PSII (F v /F m ) was significantly higher in field-collected algae and after 7 d incubation in winter than in summer. In rocky shores and rockpools thalli, maximum electron transport rate (ETR max ) and photosynthetic efficiency (a ETR ) were much higher in summer than in winter. ETR of outdoor-grown thalli (in situ ETR) showed a daily pattern, with a decrease at noon in both winter and summer (3 rd and 7 th days). We found much higher antioxidant activity in thalli collected in summer than in winter. However, the concentration of internal UV screen substances (polyphenols) was higher in winter than in summer, whereas the release of phenolic compounds was lower. The highest capacity of acclimation in C. tamariscifolia found in summer and RS with emersion periods was explained by the highest dynamic photoinhibition, energy dissipation (non-photochemical quenching) and antioxidant activity (EC 50 ).Keywords: antioxidant activity; Cystoseira tamariscifolia; phenolic compounds; photoinhibition; photoprotection. Patrones estacionales de fotoaclimatación en el alga intermareal, Cystoseira tamariscifolia (Ochrophyta)Resumen: Talos de Cystoseira tamariscifolia recolectados en pozas y plataformas rocosas intermareales (Sur de España) en invierno y en verano se incubaron bajo radiación solar durante 7 días en recipientes cilíndricos de metacrilato transparentes a la radiación UV. Se estimó la actividad fotosintética a través de la fluorescencia de la clorofila a asociada al fotosistema II, el contenido de pigmentos fotosintéticos y compuestos fenólicos, actividad antioxidante y el contenido total en C y N internos tras 3 y 7 días de incubación. Los valores iniciales del rendimiento cuántico máximo (F v /F m ) fueron significativamente mayores en algas recolectadas en invierno que en verano mientras que la tasa de transporte electrónico máximo (ETR max ) y la eficiencia fotosintética fueron mayores en verano que en invierno en ambas zonas. Por otra parte, la tasa de transporte electrónico determinada bajo radiación solar presentó un patrón diario, con una disminución a mediodía, tanto en invierno como en los períodos de verano. La actividad antioxidante fue mayor en algas recogidas en verano; sin embargo, la concentración interna de compuestos fenólicos fue mayor en invierno que en verano, mientras que en la tasa de excreción se observó lo contrario. La alta capacidad de aclimatación en C. tamariscifolia en algas sometidas a emersión en las plataformas rocosas en verano se explica por su alta fotoinhibición dinámica, su c...

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Resumen.-Durante los últimos años se ha producido un notable progreso en el número de registros sobre el tamaño del genoma para el grupo de las plantas. Sin embargo, todavía se requiere más información. Concretamente, en el caso de las algas rojas (Rhodophyta), de las ~7.000 especies descritas hasta la fecha, sólo existen datos para 196 (~3%). Esta investigación representa la primera estimación del tamaño del genoma del alga roja endémica del Pacífico Sudeste Gelidium chilense, proporcionando además características nucleares de la especie tales como tamaño y número por célula. Los contenidos de ADN nuclear fueron estimados a partir de las observaciones realizadas en 153 núcleos teñidos con DAPI. Las células de G. chilense mostraron una variación del contenido de ADN nuclear intraplanta de 0,2-4,0 pg. En total, 6 niveles de ploidía fueron observados en esta especie. El nivel 1C fue observado solo en las células corticales mientras que el mayor nivel de ploidía (16C) fue observado en los tetrasporangios. Los valores obtenidos en los tetrasporangios indicaron que el tamaño del genoma aumenta durante la tetrasporogenesis mediante endopoliploidía (desde 4C a 16C). Por otra parte, el menor nivel de ploidía observado en las tetrasporas correspondió al 3C, lo que confirma la hipótesis de que la meiosis no ocurre en los esporangios de G. chilense. Este trabajo de investigación contribuye al conocimiento de las estrategias reproductivas relacionadas con el ciclo biológico en las especies del orden Gelidiales.Palabras clave: Contenido de ADN nuclear, endoreduplicación, Gelidium, ciclo biológico, poliploidía Abstract.-There has been progress in novel additions of algal data to the Plant DNA C-values database during recent years; however more information is still required. Specifically, in the case of red algae (Rhodophyta), from ~7000 species described up to date, DNA C-values for only 196 species have been incorporated (~3%). This research represents the first estimation of genome size for the Southeast Pacific endemic red alga Gelidium chilense and provides nuclear features such as number per cell and size. Nuclear DNA content estimates were obtained from measurements of 153 DAPI-stained nuclei. The cells of G. chilense showed intra-plant variation with DNA content values ranging from 0.2-4.0 pg and a total of 6 ploidy levels were found. The lowest level (1C) was observed only in outer cortical cells whereas tetrasporangia displayed the highest levels (16C). The nuclear DNA contents obtained in tetrasporangia indicated that the genome size increases during tetrasporogenesis by endopolyploidy (from 4C to 16C). In addition, the minimum value observed in tetraspores corresponds to a 3C. Our results confirm the hypothesis that meiosis does not occur within the sporangia in G. chilense. This study contributes to knowledge of reproductive strategies related with the life history of Gelidiales.

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New data on synonymy and typifi cation of Dasya species of the western Mediterranean are provided, including: D. baillouviana (S. G. Gmel.) Mont., D. corymbifera J. Agardh, D. hutchinsiae Harv., D. ocellata (Gratel.) Harv., D. rigescens Zanardini, D. rigidula (K ü tz.) Ardiss., D. sessilis Yamada and D. punicea (Zanardini) Menegh. in Zanardini. Data on synonymy and a brief nomenclatural story are shown for each species, a lectotype and a neotype are selected respectively for D. rigidula and D. punicea and clarifi cation of neotype designation is discussed for D. corymbifera .Dasya C. Agardh includes red algae with hairy and delicate appearance and rigid to fl accid texture. Th e thalli are 0.5 -30.0 cm high and deep red or brownish to purplishred with axes erect, with sympodial branching and radially organized, polysiphonous, with (4 -) 5 periaxial cells, slightly to strongly corticated by rhizoidal fi laments. Th e pseudolaterals are spirally arranged, one per segment and subdichotomously branched. Th e tetrasporangia appear in modifi ed axes (stichidia), arranged in whorls (4 -7 per segment) and the gametophytes are dioecious. Th e spermatangia are borne in whorls, in monosiphonous axes.

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A detailed study of the original material of Dasya ocellata and related taxa revealed that the current concept of the species is not fully coincident with that of its basionym, Ceramium ocellatum. The original material is conserved at LD, and consist of two specimens affixed on the same voucher and these do in fact belong to two different species. One of them, which was selected as the lectotype, fits the current concept of D. ocellata whilst the other corresponds to D. hutchinsiae. Although the former specimen is not apparently the best to fit the protologue, it is not in serious conflict with it, and that choice ensures the traditional usage of the name. Several nomenclatural and historical features related to the name are also discussed.