Twelve stream segments were sampled four times in 1998-1999 (one sampling per season) in the drainage basin of the upper São Francisco River (19 masculine 45'-21 masculine 25'S, 49 masculine 05'-51 masculine 30'W), situated in Serra da Canastra National Park, at altitudes ranging from 1,175 to 1,400 m. The macroalgae survey resulted in 30 species, with a predominance of Cyanophyta (12 species = 40%) and Chlorophyta (11 species = 36.5%) and a lower proportion of Rhodophyta (seven species = 23.5%). Two species, Klebsormidium rivulare (Chlorophyta) and Kyliniella latvica (Rhodophyta), were new records for Brazil. Capsosira sp. and Stigonema sp. (Cyanophyta) and the "Chantransia" stage of Batrachospermum (Rhodophyta) were the most widespread macroalgae, occurring in six sampling sites, whereas 11 species were found at only one site. The proportion of macroalgal morphological types were as follows: mats (33%), free filaments (27%), gelatinous filaments (27%), crusts (7%), tufts (3%), and gelatinous colonies (3%). The flora revealed few species in common (4%-8%) with stream macroalgae from other Brazilian regions. The macroalgal communities proved to have species richness values close to the highest values reported in previous studies. The patterns typical for stream macroalgal communities (patchy distribution and dominance of few species) were also found in this basin. However, the stream variables most influential in macroalgal distribution in this study (rocky substratum, low pH, high COD, water color, and current velocity) were essentially the same that best describe the limnological characteristics of this lotic ecosystem. In addition, this combination of variables differed sharply from results of previous studies in other Brazilian stream ecosystems.

Photoacclimation of photosynthesis was investigated in a tropical population of C. glomerata (São Paulo State, southeastern Brazil, 20° 48' 24" S and 49° 22' 24" W) by chlorophyll fluorescence parameters and chlorophyll a content. Plants were acclimated to two levels of irradiance: low (65 ± 5 mmol.m -2 .s -1 ) and high (300 ± 10 mmol.m -2.s -1 ) and exposed short-term (4 days) and long-term (28 days) under a light-dark cycle of 12:12 hours. Photosynthesis-irradiance (PI) curves revealed distinct strategies of photoacclimation. In long-term exposure, plants acclimated by altering the photosynthetic units (PSU) number and keeping fixed the PSU size, revealed by increased rates of maximum photosynthesis (P max ), lower photosynthetic efficiency (alpha) and higher values of the saturation parameter (I k ) under high irradiance. The short-term acclimation strategy consisted of changing the PSU size, with a fixed number of PSUs, as revealed by similar P max but higher alpha and lower I k under low irradiance. Chlorophyll a contents followed the general pattern reported in green algae of higher concentrations under lower irradiance. Dark/light induction curves revealed consistently higher values of potential quantum yield under low irradiance. Initial and final values showed a higher recovery capacity in the short (84.4-90.6%) term exposure than in the long-term case (81.4-81.5%). ETR (electron transport rate) and NPQ (non-photochemical quenching) values were consistently higher under low irradiance. ETR showed a continuous and steady increase along the light exposure period in the short and long-term experiments, whereas NPQ values revealed a rapid increase after 15 seconds of light exposure, kept a slightly increasing trend and stabilized in most treatments. Lower photosynthetic performance (ETR) and recovery capacity of potential quantum yield were observed, particularly in long-term exposure, suggesting that this population is constrained by the typical high light environment of tropical regions.Keywords: acclimation, Cladophora, light, macroalgae, photosynthesis, tropical. ) e expostas a curto período (4 dias) e longo período (28 dias) em fotoperíodo de 12 horas. Curvas de fotossíntese-irradiância (FI) revelaram estratégias distintas de fotoaclimatação. Plantas expostas a longo período aclimataram pela alteração do número de unidades fotossintéticas (UF) e mantiveram fixo o tamanho das UF. Estas características foram reveladas por menores taxas de fotossíntese máxima (F max ), menor eficiência fotossintética (alfa) e valores mais altos do parâmetro de saturação (I k ) em alta irradiância. A estratégia de aclimatação em curto período consistiu em mudança no tamanho das UF, com número fixo de UF, conforme revelado por taxas semelhantes de fotossíntese máxima (F max ), maiores valores de alfa e menores de I k em baixa irradiância. Os conteúdos de clorofila a seguiram o padrão geral reportado para algas verdes de maiores concentrações em baixa irradiância. Curvas de indução escuro/luz revelaram valores consi...

RESUMO -(Novas morfoespécies aerofíticas de Cyanobacteria de fragmentos de fl oresta tropical na região noroeste do Estado de São Paulo, Brasil). Algas e cianobactérias podem colonizar uma grande variedade de ambientes terrestres e a composição fl orística das comunidades desses habitats é praticamente desconhecida. Durante o estudo das algas e cianobactérias aerofíticas de fragmentos fl orestais na região noroeste do estado de São Paulo, seis populações de cianobactérias não puderam ser identifi cadas em nível específi co e, após estudos morfológicos e métricos, revelaram-se novos morfotipos para a Ciência. Quatro desses pertencem ao gênero Aphanothece (A. excentrica, A. coacervata, A. densa e A. vaginata), um a Phormidium (P. arboricola) e um a Hapalosiphon (H. santannae). Este estudo apresenta a descrição, comparação e proposição das novas morfoespécies e contribui com o conhecimento da diversidade do grupo. Palavras-chave: Cyanobacteria aerofíticas, fl oresta estacional semideciadual, novas morfoespécies ABSTRACT -(New aerophytic morphospecies of Cyanobacteria from tropical forest fragments in northwestern São Paulo state, Brazil). Algae and Cyanobacteria can colonize a wide variety of terrestrial environments and the assemblages from aerophytic habitats are very poorly known. During the survey of aerophytic algal and cyanobacterial communities in forest fragments in northwestern São Paulo state, six cyanobacteria populations could not be identifi ed at species level and, after morphological and metrical analysis, proved to be new morphotypes to Science. Four belong to the genus Aphanothece (A. excentrica, A. coacervata, A. densa and A. vaginata), one to Phormidium (P. arboricola) and one to Hapalosiphon (H. santannae). This study presents the description, comparison and proposition of the new morphospecies and improves taxonomic knowledge of the diversity of the group. Key words: Aerophytic Cyanobacteria, new morphospecies, seasonal semidecidous forest 917 Lemes-da-Silva et al.: New aerophytic morphospecies of Cyanobacteria from tropical forest fragments in northwestern... Material and methodsSampling was carried out between March and May, 2007, in seasonal semideciduous forest fragments occurring in northwestern São Paulo state (Tab. 1).Detailed description of collection, preservation and study can be found in Lemes-da-Silva et al. (2010). In short, visible growths of algae, cyanobacteria and bryophytes were collected from randomly selected tree bark. The dried material was taken to the laboratory, rehydrated and analyzed under stereoscope microscope and light microscope. For each population found, at least 20 observations of each qualitative or quantitative taxonomic characteristic were made. The taxa found were described according to the patterns adopted for each group and the following abbreviations were used for species description in text and tables: diam. (diameter) and L/D (cell length/diameter ratio).The classifi cation system used was that of Hoffmann et al. (2005); holotypes are deposited in the...

-(Corticolous green algae from tropical forest remnants in the northwest region of São Paulo State, Brazil). The algae inhabit a wide variety of terrestrial environments and substrates; however the taxonomic knowledge for tropical regions is still scarce. This survey was conducted in ten forest remnants in São Paulo State where visible growths of algae and bryophytes were collected and studied for the main algal components of the communities. Results reveal the occurrence of nine species of green algae, distributed through the class Trebouxiophyceae (one species), Charophyceae (one species) and Ulvophyceae (seven species). Desmococcus olivaceus (Persoon ex Archerson) J. R. Laundon and Printzina effusa (Krempelhüber) Thompson & Wujek are new records for Brazil. The most frequent organisms found in the areas pertain to Trentepohliales that is mainly represented by Trentepohlia species. On the basis of results found, it is recommended that such communities receive more attention in future investigations to improve the knowledge about this important group of primary producers.Key words -Brazil, seasonal semideciduous forest, terrestrial algae, Trentepohlia RESUMO -(Algas verdes corticícolas de remanescentes de fl oresta tropical na região noroeste do Estado de São Paulo, Brasil). As algas habitam uma grande variedade de ambientes e substratos terrestres; entretanto o conhecimento taxonômico para as regiões tropicais ainda é escasso. Esse levantamento foi conduzido em 10 fragmentos fl orestais no Estado de São Paulo, onde crescimentos visíveis de algas e briófi tas foram coletados e os principais componentes da comunidade algal foram estudados. Os resultados revelaram a ocorrência de nove espécies de algas verdes, distribuídas nas classes Trebouxiophyceae (uma espécie), Charophyceae (uma espécie) e Ulvophyceae (sete espécies). Desmococcus olivaceus (Persoon ex Archerson) J. R. Laundon e Printzina effusa (Krempelhüber) Thompson & Wujek são novos registros para o Brasil. Os organismos mais frequentes nas áreas pertencem a Trentepohliales, que foi representado principalmente por espécies de Trentepohlia. Baseado nos resultados encontrados, é recomendado que tais comunidades recebam mais atenção em investigações futuras para aumentar o conhecimento sobre esse importante grupo de produtores primários.Palavras-chave -algas terrestres, Brasil, fl oresta estacional semidecidual, Trentepohlia 1.

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