Adições à Brioflora do Parque Estadual do Ibitipoca, Minas Gerais, Brasil

O presente estudo trata das briófitas do Parque Estadual do Ibitipoca, coletadas por diferentes pesquisadores e depositadas no Herbário Maria Eneyda P. Kauffmann Fidalgo (SP). São reportados 238 táxons de briófitas, dos quais 136 são hepáticas (em 16 famílias) e 102 são musgos (em 25 famílias), sendo 30 novas referências para o estado de Minas Gerais (09 espécies de musgos e 21 espécies de hepáticas). Estes dados representam uma adição de cerca de 15% do total de táxons indicados para a área

Morphology of pollen grains and orbicules of two threatened species of Cedrela P. Browne (Meliaceae A. Juss.)

Abstract Pollen grain morphology and the characterization of additional structures related to pollen dispersion can help to understand the strategies presented by species as well as their taxonomic circumscription. This work investigates the morphology of pollen grains and orbicules of Cedrela fissilis Vell. and Cedrela odorata L., two threatened species of the genus Cedrela P. Browne (Meliaceae A. Juss.) in Brazil. Observations of pollen grains and orbicules of the species were carried out pre- and post-chemical treatment of the samples, under light and scanning electron microscopy, aiming at recognizing structures, detailing morphological characterizations and taking measurements, the last of which were submitted to statistical treatment. The results demonstrate that the pollen grains of the two species are medium in size (measuring between 25 and 50µm), radially symmetrical, isopolar, prolate-spheroidal and 4,5-colporate with subcircular to subquadrangular amb and psilate ornamentation; the orbicules also have a smooth surface and measure about 7 to 10µm. Variation was observed in the size of pollen grains, which presented high coefficient of variation and in the orbicules, as well as in the number of apertures

Sex Differences in Desiccation Tolerance Varies by Colony in the Mesic Liverwort \u3ci\u3ePlagiochila porelloides\u3c/i\u3e

Water scarcity, a common stress factor, negatively impacts plant performance. Strategies to cope with it, such as desiccation tolerance, are becoming increasingly important to investigate. However, phenomena, such as intraspecific variation in stress responses have not received much attention. Knowledge of this variability and the environmental drivers can be leveraged to further investigate the mechanisms of desiccation tolerance. Here we tested for variation in desiccation tolerance in Plagiochila porelloides among colonies and sexes within the same riparian zone. Field-collected dehardened plants were subjected to a desiccation event, under controlled conditions and then rehydrated. Plant water status, photosynthetic rates, net carbon gain, and efficiency of photosystem II (PSII) were assayed to evaluate tissue desiccation, basic metabolic processes and plant recovery. To establish a linkage between plant response and environmental factors, field light conditions were measured. We detected intraspecific variation, where a more exposed colony (high percentage of open sky, large temporal range of light quantity, and high red/far-red ratio) showed sex differences in desiccation tolerance and recovery. Overall, PSII recovery occurred by 72 h after rehydration, with a positive carbon gain occurring by day 30. This within species variation suggests plastic or genetic effects, and likely association with light conditions

Spore morphology of Polytrichaceae Schwägr. (Bryophyta) from Brazil

Spore morphology is described for all six genera of Brazilian Polytrichaceae based on light and scanning electron microscopy study of 13 species of the approximately 30 species of the family native to the country. Discussion on its taxonomic importance is also provided. Spores were analyzed before and after the acetolysis method. Polytrichaceae is eurypalynous. The spore surface of Atrichum androgynum (Müll. Hal.) A. Jaeger has regular granules and isolated gemmae. The spores of Itatiella P. Beauv. and Oligotrichum Lam. & DC. species are small to medium size, with bacula, elongated processes, clavae and pila on the surface. Species of Pogonatum P. Beauv. gathers spores of very small to small size, granulate surface. Polytrichadelphus pseudopolytrichum (Raddi) G. L. Sm. spores are very small to small size, and ornamentation formed by reduced smooth spines. In Polytrichum Hedw. species the spores are small and ornamentation is formed by ornamented spine-like processes to granules.A morfologia dos esporos é descrita para todos os seis gêneros de Polytrichaceae ocorrentes no Brasil baseando-se no estudo, em microscopia de luz e eletrônica de varredura, de 13 das aproximadamente 30 espécies da família nativas para o país. Também é apresentada a discussão sobre sua importância taxonômica. Os esporos foram estudados antes e após o método da acetólise. Os resultados indicam Polytrichaceae como euripalinológica. A superfície dos esporos de Atrichum androgynum (Müll. Hal.) A. Jaeger é formada por grânulos regulares, com gemas isoladas. Os esporos de Itatiella ulei P. Beauv. e das espécies de Oligotrichum Lam. & DC. são de tamanho pequeno a médio, com báculos, processos alongados, clavas e pilos na superfície. Espécies de Pogonatum P. Beauv. possuem esporos de tamanho muito pequeno a pequeno, com superfície granulada. Os esporos de Polytrichadelphus pseudopolytrichum (Raddi) G. L. Sm. são de tamanho muito pequeno a pequeno, com ornamentação formada por diminutos espinhos lisos. Nas espécies de Polytrichum Hedw., os esporos são de tamanho pequeno e a ornamentação é formada por processos espinhosos ornamentados a grânulos

Spores morphology from Sematophyllaceae Broth. from three fragments of Mata Atlântica, in Rio de Janeiro, Brazil

In the present work the spores of seven species of the family Sematophyllaceae Broth. (Bryophyta) from three areas of Mata Atlântica were analyzed. For the spores' external morphology analysis, the direct method in glycerined gelatin was used and for the measurements the method of acetolysis was used. The largest and smaller diameters (in polar view) and the thickness of the wall were measured. The analysis was carried under optical microscope and scanning electronic microscope. The spores are isomorphic, from small to medium size, heteropolars, of subcircular amb, with proximalapertural region and granulated surface. The apertural region is irregular. The variations found between the spores of the different species are related to the size of the spores and the distribution of the trimming elements.No presente trabalho foram analisados os esporos de sete espécies da família Sematophyllaceae Broth. (Bryophyta) ocorrentes em três áreas de Mata Atlântica. Para análise da morfologia externa dos esporos, utilizou-se o método direto em gelatina glicerinada e para as medidas foi utilizado o método de acetólise. Foram medidos os diâmetros maior e menor (em vista polar) e a espessura da parede. As análises foram realizadas sob microscópio de luz e microscópio eletrônico de varredura. Após a realização das medidas, realizou-se a análise estatística e estas foram apresentadas em tabelas. Os esporos são isomórficos, de tamanho pequeno a médio, heteropolares, de amb subcircular, com região apertural proximal e superfície granulada. A região apertural é irregular. As variações encontradas entre os esporos das diferentes espécies estão relacionadas ao tamanho dos esporos e à distribuição dos elementos de ornamentação

Spore germination, early development and some notes on the effects of in vitro culture medium on Frullania ericoides (Nees) Mont. (Frullaniaceae, Marchantiophyta)

In bryophytes, establishment can occur by a sexual or asexual process, but the production of spores enables colonization of a wider range of habitats and substrates than can asexual propagules. Successful germination is critical for establishment in a new environment. This paper addresses germination and sporeling development in Frullania ericoides, a leafy liverwort species. Fresh spores were inoculated in vitro in different culture strengths of Knop’s nutrient solution (one-fourth strength, half strength, full strength, one and a half strength and double strength), in order to evaluate the effects of this solution on spore germination and on the development of external protonema. On the first assessment, spore germination was observed at all the concentrations. Germination was endosporic, with cell division and proliferation, resulting in a globular protonema, within the spore wall. Beginning at the fourth week, the development of tightly concave primordial leaves was observed in all but the double-strength medium. Throughout the period of study, the treatments with lower concentrations exhibited external protonema with greater lengths. The double-strength treatment was statistically different from other treatments in at least two parameters. The results of this study demonstrate the potential of in vitro culture techniques for bryophyte spore studies and germplasm preservation.

Briófitas da Serra de Ibitipoca(MG): estudo taxonômico do acervo do Herbário Professor Leopoldo Krieger, da Universidade Federal de Juiz de Fora

-As plantas terrestres criptogâmicas, avasculares que apresentam uma alternância de gerações na qual o gametófito haplóide, clorofilado é a fase dominante do ciclo de vida são, em conjunto, chamadas de “briófitas”. A reprodução sexual é oogâmica (o gameta masculino é flagelado); os órgãos sexuais (arquegônios e anterídios) apresentam uma parede de células estéreis. Após a fertilização, a parede do ventre do arquegônio aumenta, formando uma capa de proteção (a caliptra) em torno do embrião em desenvolvimento, que não apresenta fase de dormência. Dados de diferentes autores indicam que o maior número de trabalhos sobre briófitas no Brasil tem sido desenvolvido nas regiões sul e sudeste do país; no entanto, há importantes lacunas no conhecimento da flora briológica do estado de Minas Gerais. Desta forma, o estudo do acervo dos diferentes herbários do estado possibilitam um incremento das informações sobre estas plantas. As listas das espécies de “briófitas” do Parque Estadual do Ibitipoca (MG), aqui apresentadas, resultam do estudo do acervo do Herbário Prof. Leopoldo Krieger, da Universidade Federal de Juiz de Fora. Tal estudo compreendeu o resgate da coleção briológica, a organização das exsicatas, o levantamento do material botânico, a identificação das espécies e a informatização dos dados obtidos. Foram observadas 83 espécies de hepáticas e musgos; antóceros não foram registrados na coleção até o momento. As hepáticas presentes no acervo perfazem um total de 31 espécies, incluídas em 11 famílias: Bryopteridaceae R. Stotler, Herbertaceae Müll. Frib. ex Fullford & Hatcher, Jubulaceae H. Klinggr., Lejeuneaceae Cas.-Gil, Lepidoziaceae Limpr., Marchantiaceae (Bisch.) Lindl., Metzgeriaceae H. Klinggr., Pallaviciniaceae Mig., Plagiochilaceae (Jörg.) Müll. Frib. & Herzog, Porellaceae Cavers e Radulaceae (Dumort.) K. Müller. No que diz respeito aos musgos, compreendem 52 espécies pertencentes a 22 famílias: Bartramiaceae Schwägr., Brachytheciaceae Schimp., Bryaceae Schwägr., Calymperaceae Kindb., Daltoniaceae Schimp., Dicranaceae Schimp., Entodontaceae Kindb., Grimmiaceae Arn., Hypnaceae Schimp., Lembophyllaceae Broth., Leucobryaceae Schimp., Neckeraceae Schimp., Orthotrichaceae Arn., Phyllogoniaceae Kindb., Pilotrichaceae Kindb., Polytrichaceae Schwägr., Pottiaceae Schimp., Rhacocarpaceae Kindb., Rhizogoniaceae Broth., Sematophyllaceae Broth., Sphagnaceae Dumort. e Thuidiaceae Schimp. Foi possível observar que o substrato preferencial foi o corticícola, seguido do terrestre e do rupícola e, as plantas epixilas foram as menos coletadas. Acredita-se que isto reflita o menor esforço de coleta nas áreas de florestas nebular e ombrófila. Neste momento, iniciamos o desenvolvimento de um projeto que prevê a realização de coletas no Parque Estadual do Ibitipoca, visando enriquecer os dados acerca das espécies que ocorrem na área, especialmente, nas regiões de floresta

Distribution of bryophytes in south-eastern Brazil: an approach on floristic similarity and environmental filtering

The south-eastern Brazil comprises the Atlantic forest (a region mainly characterized by tropical evergreen forest), subtropical forest, mangroves, and scrub sandbanks. Sandy areas are found at sea level, and high altitude grassland spots and rocky outcrops occur above 2000 m. This region is important because the richness, diversity, and endemism of species, including bryophytes. The similarity of bryophytes occurring on these different areas has not been evaluated yet. This study aimed to analyse the bryofloristic similarity between 12 different areas in south-eastern Brazil, assessing the environmental factors that influence their distribution. Floristic similarity was analysed under cluster and Detrended Correspondence Analysis; multi-response permutation procedures were employed to test the groups’ significance. In order to test whether the geographical distance between the areas is a relevant factor to test the similarity of the species, Spearman correlation analysis was performed, and to determine the relationship between the floristic composition and the environmental variables (altitude, temperature, annual rainfall and distance from the ocean), canonical correspondence analysis was applied. A low similarity between the 12 studied areas was observed, but two groups were revealed, the so-called inland areas and coastal areas. The annual precipitation and annual temperature influenced floristic similarity in the coastal areas and, the distance from the ocean and altitude were the variables that most influenced inland areas.</p