Resumo em Inglês:

This work is part of a survey of the desmid flora in a tributary of the Itaipu Reservoir, in the state of Paraná, Brazil. The objective was to expand the knowledge base regarding the genus Cosmarium (Desmidiaceae, Zygnematophyceae). We conducted a qualitative analysis of 60 samples of phytoplankton, which were collected from along the banks of the São Francisco Falso River between July of 2003 and June of 2004. We identified, drew, and described 18 taxa of Cosmarium. Of those 18 taxa, 8 represent new records for the state of Paraná: C. angulosum Bréb. var. angulosum, C. bireme Nordst. var. bireme, C. clepsydra Nordst. var. clepsydra, C. cf. galeritum Nordst. var. borgei, C. ginzbergeri, C. norimbergense Reinsch var. norimbergense, C. protractum (Nägeli) De Bary var. protractum, and C. rectangulare var. hexagonum (Elfving) G.S. West & West.

Resumo em Inglês:

Butia catarinensis Noblick & Lorenzi is a small palm (approximately 2 m high when full-grown) endemic to the southern coast of Brazil. Local farmers use the fruit and pulp for various purposes, and this extractive activity complements their income. The objective of this study was to understand the relationships between local people and B. catarinensis in its natural environment. Ethnobotanical and ethnoecological data were collected through participant observation, participatory research tools and semi-structured interviews. The density of B. catarinensis was measured in two areas, each containing twelve 10 m × 20 m plots. Interviewees recognized different varieties of the palm, its phenological stages, as well as potential pollinators and seed dispersers. Eighteen different uses for the palm were registered and three different collection practices were observed, depending on the purpose for which the fruit was used. The mean density in the two areas studied ranged from 38.6 to 7.9 adults per plot. The rate of production (per hectare) can be as high as 927 kg of fruit and 190 kg of pulp. The local community can contribute to the conservation of this coastal ecosystem through extractive activities of some scale, with potential environmental, economic and socio-cultural sustainability.

Resumo em Inglês:

Plants subjected to stressful environments tend to be more asymmetric with reduced defenses and are therefore more vulnerable to herbivory. This study investigates the relationship between herbivory and fluctuating asymmetry (FA) in Poincianella pyramidalis in two contrasting habitat types in the Brazilian caatinga (shrublands). We tested the following hypotheses: that FA occurs in P. pyramidalis; that FA of P. pyramidalis leaves is greater in individuals located in pasture than in those located in secondary tropical dry forest; that herbivory by insects (leaf chewers and leaf miners) increases in parallel with increases in the level of FA; and that herbivory is more common in pasture than in secondary tropical dry forest. In each of the two environments, we sampled 20 plants and evaluated 400 leaflets. We submitted FA data to the Shapiro-Wilk test of normality, and we investigated the other variables using generalized linear models. We found that FA was present in all P. pyramidalis individuals evaluated but was greater in those located in the more degraded habitat (pasture). In addition, although herbivory was similar between the two habitats, there was positive relationship between FA and herbivory. This indicates that herbivores select plants that are more asymmetric, regardless of the type of habitat involved, which might be attributable to the mechanisms posited in the plant stress hypothesis.

Resumo em Inglês:

Regnellidium diphyllum Lindm. is a heterosporous fern growing in wetlands and humid soils that are being converted to agricultural activities. Many products that are used in agriculture contain copper, resulting in surface and groundwater contamination. Germination and initial development tests were performed using Meyer's solution containing copper sulphate at concentrations of 0 (control), 1, 5, 10, 50 and 100 mg L-1. The experiment was conducted in a growth chamber at 25 ± 1ºC for 28 days, with a 12/12-hour light/dark cycle and a photon flux density of 100 µmol m-2 s-1. The lowest germination rate (6%) was observed at 100 mg L-1. Primary root growth was significantly reduced at > 10 mg L-1. Secondary leaves of sporophytes grown in concentrations > 5 mg L-1 were progressively shorter than were those formed by the control plants. We conclude that the release of pollutants containing copper into the natural habitats of R. diphyllum can cause phytotoxicity, threatening the establishment of populations and worsening the already vulnerable conservation status of this species.

Resumo em Inglês:

We analyzed specimens identified as Amanita muscaria, some recently collected and others already deposited in herbaria, in Brazil. We concluded that two subspecies of A. muscaria occur in Brazil: A. muscaria var. muscaria; and A.muscaria var. flavivolvata. The first taxon was found in association with Castanea sativa, and the second (one specimen only) was found in association with Pinus and Eucalyptus spp. Morphologically, A. muscaria var. flavivolvata is distinguished by a shallower subhymenium and by basidiospores that are more elongated than are those of A. muscaria var. muscaria, which is the more widely known subspecies. We present descriptions, discussions, illustrations and a dichotomous key for these two subspecies.

Resumo em Inglês:

The native forests once occupying the coastal levees of the Lower Delta islands of the Paraná River (in Argentina) have been replaced by commercial forests. Many of those forests have been abandoned, resulting in secondary forest formation that is subject to numerous invasive exotic species. A priori observations suggest that successional trends do not lead to recovery of the original forest. The aim of the present study was to analyze the role of invasive exotic species in these environments and the likelihood of recovery of the original forest cover. Therefore, we examined the composition of the seed bank and of the standing vegetation, as well as the population structure of tree species. Secondary forests are described as being in an intermediate successional stage, with few exotic species (mainly trees) but with a high abundance of standing vegetation and seed banks. These exotic species will likely continue to successfully predominate in different forest strata over the next stages. Because of the low density of native tree species, it is difficult to predict their future persistence. In conclusion, ecological restoration strategies will be needed in order to increase native tree species richness and biodiversity of the forests in the Lower Delta of the Paraná River.

Resumo em Inglês:

Most studies conducted to test the allelopathic activity of plant parts have made use of water as solvent. However, the presence of polar, water-soluble substances, such as proteins and carbohydrates, tends to hamper the purification of active compounds. In this study, we present a simple purification procedure that separates the active fraction of the extract from the undesirable substances, thus facilitating the search for active molecules through standard chromatographic methods. Aqueous leaf extracts of three Cerrado species (Caryocar brasiliense, Qualea parviflora and Eugenia dysenterica) were prepared at 5% concentration (w/v) and stored at 4ºC (crude extracts). After 24 h, these solutions were filtered and freeze-dried. The powder obtained was dissolved in methanol, filtered again, evaporated and dissolved in water for bioassays (purified extracts). For the bioassays, seedlings of Sesamum indicum were grown for five days in aqueous solutions prepared from crude and purified extracts at concentrations ranging from 0.1% to 1.0% (w/v). Seedling growth in distilled water was set as a control. In comparison with the control, we found that test solutions prepared from both crude and purified extracts significantly inhibited sesame seedling growth. However, solutions prepared from purified extracts were two to ten times more inhibitory to seedling growth than were those prepared from crude extracts. The inhibition of root growth ranged from 35% to 77%, depending on the plant species, at a concentration as low as 0.1%. Roots were more affected than were shoots. The effects of purified extracts on seedling morphology were similar to those observed when crude extracts were employed, indicating that the procedure of purification of crude extracts did not interfere with the mode of action of the active substances

Resumo em Inglês:

Allelopathy is a type of biotic interference wherein a plant releases bioactive metabolites into an environment, thereby affecting the adjacent biota. Stressful environments stimulate the production of these metabolites. The present study tests the novel weapons hypothesis, which postulates that species belonging to the same genus and from the same environment have similar allelopathic effects. The aim of this study was to assess the allelopathic effects that the aqueous leaf extracts of 15 species belonging to five genera of the Myrtaceae family have on the seed germination and initial seedling growth of lettuce (Lactuca sativa L.), tomato (Solanum lycopersicum L.) and onion (Allium cepa L.). Germination rates, average germination times, informational entropy of germination and allelopathic effects, as quantified with a response index, were calculated. A taxonomic distance matrix based on Gower dissimilarity and a Euclidean distance matrix were constructed. The results revealed that all extracts from donor species significantly increased average germination time or reduced the germination rate of eudicotyledonous plant species. The only extracts that showed no effect on monocotyledonous seeds were those of Campomanesia pubescens O. Berg and Psidium cinereum Mart. We conclude that eudicotyledonous and monocotyledonous plants were both significantly affected by the presence of all extracts tested. Our results make it clear that each species behaves distinctly in relation to allelopathic activity, with no apparent grouping by genus or subtribe. Therefore, the hypothesis was rejected, because plants from the same environment and with taxonomic proximity do not necessarily display similar production of secondary metabolites.

Resumo em Inglês:

The aim of this study was to evaluate the phytotoxic potential of aqueous extract of young leaves of Sapindus saponaria L. (soapberry) on the diaspore germination and seedling growth Lactuca sativa L. (lettuce) and Allium cepa L. (onion), as well as to determine, by bioassay-guided fractioning, whether the fractionated extracts of those leaves are phytotoxic to Triticum aestivum L. (wheat) coleoptiles. The aqueous extract was prepared using 100 g of dried plant material dissolved in 1000 ml of distilled water, resulting in a concentration of 10.0%. Distilled water was added in order to obtain dilutions of 7.5%, 5.0%, and 2.5%. The extraction was carried out with young leaves (in powder form) and organic solvents of various polarities. We fractioned the ethyl acetate extract using column chromatography. The phytotoxic potential of the aqueous extract of young leaves S. saponaria varied according to the receiving species and the concentration-dependent inhibitory effect. The ethyl acetate extract, specifically fraction 6 (57-70), had the greatest inhibitory effect on the elongation of wheat coleoptiles, indicating that the compounds responsible for the phytotoxic effect reside within this fraction.

Resumo em Inglês:

The aim of this work was to evaluate the floristic composition, richness, and diversity of the upper and lower strata of a stretch of mixed rain forest near the city of Itaberá, in southeastern Brazil. We also investigated the differences between this conservation area and other stretches of mixed rain forest in southern and southeastern Brazil, as well as other nearby forest formations, in terms of their floristic relationships. For our survey of the upper stratum (diameter at breast height [DBH] > 15 cm), we established 50 permanent plots of 10 × 20 m. Within each of those plots, we designated five, randomly located, 1 × 1 m subplots, in order to survey the lower stratum (total height > 30 cm and DBH < 15 cm). In the upper stratum, we sampled 1429 trees and shrubs, belonging to 134 species, 93 genera, and 47 families. In the lower stratum, we sampled 758 trees and shrubs, belonging to 93 species, 66 genera, and 39 families. In our floristic and phytosociological surveys, we recorded 177 species, belonging to 106 genera and 52 families. The Shannon Diversity Index was 4.12 and 3.5 for the upper and lower strata, respectively. Cluster analysis indicated that nearby forest formations had the strongest floristic influence on the study area, which was therefore distinct from other mixed rain forests in southern Brazil and in the Serra da Mantiqueira mountain range.

Resumo em Inglês:

The Brazilian shrublands area (restinga) is composed of marine coast vegetation on Quaternary sandy plains, where the species composition can vary depending on the surrounding ecosystems. The aims of this study were to describe the structure and floristic composition of a restinga near the community of Itaúnas, in the northern part of the state of Espírito Santo, to identify any relationships between this restinga and surrounding plant formations, and to determine which are the species that occur preferentially in the coastal forests of Espírito Santo. We sampled woody plants with a diameter at breast height > 2.5 cm, excluding lianas, in 50 plots of 100 m². We selected studies of coastal forests in the states of Espírito Santo and Bahia to prepare a database that would reveal patterns of floristic variation among these areas. We used t wo-way indicator species analysis for the identification of the species that occur preferentially in the coastal forests of Espírito Santo. We identified 114 species belonging to 38 families. Species richness was greatest for Myrtaceae (26 species), followed by Fabaceae (10). The Shannon index for the study area was 3.96. The estimated total density was 3,330 individuals/ha and basal area was 32.02 m²/ha. The highest importance value (IV) was for Protium heptaphyllum (IV, 23.4), indicating that it is characteristic of the Espírito Santo restinga. The results of our floristic analysis indicate that the species composition of the Itaúnas restinga is influenced by the so-called tabuleiro forests (coastal lowland forests on Tertiary deposits), which are most common in northern Espírito Santo. This seems to be the main factor responsible for the gradual reduction in floristic similarity between the restingas in the north of Espírito Santo and those in the south of the state, each constituting a distinct floristic block. In addition, we generated lists of species that occur preferentially in the restinga and tabuleiro forests. Those lists could inform decisions regarding environmental restoration programs.

Resumo em Inglês:

This study represents a taxonomic survey of class Bacillariophyceae diatoms found in samples collected in the Iguaçu River (Iguaçu National Park, municipality of Foz do Iguaçu, in the state of Paraná, Brazil) between August 2007 and July 2008. Two sampling stations were utilized, the first located upstream of Iguaçu Falls (Cais Bananeiras Station) and second downstream of the falls (Cais Macuco Safari Station). The study resulted in the identification of 86 taxa, including 74 at the specific level and seven taxonomic varieties. Two of these had never before been documented in the state of Paraná: Gomphonema gibberum Hustedt and Pinnularia meridiana Metzeltin & Krammer. Nine are first-time records for Brazil: Cymbella charrua Metzeltin, Lange-Bertalot & García-Rodríguez, Placoneis ovillus Metzeltin, Lange-Bertalot & García-Rodríguez, Gomphonema affinopsis Metzeltin, Lange-Bertalot & García-Rodríguez, , Gomphosphenia lingulatiformis (Lange-Bertalot & Reichardt) Lange-Bertalot, Luticola aequatorialis (Heiden) Lange-Bertalot & Ohtsuka, Sellaphora garciarodriguezii Metzeltin & Lange-Bertalot, Eolimna submuralis (Hustedt) Lange-Bertalot Kulikovskiy, Geissleria neosubtropica Metzeltin, Lange-Bertalot & García-Rodríguez and Stauroneis cf. sylviabonillae Metzeltin, Lange-Bertalot & García-Rodríguez.

Resumo em Inglês:

This study aims to investigate the richness and ecological aspects (ecosystem and substrate) of mosses and liverworts at two municipalities on Marajó Island, in the state of Pará, Brazil. The study area (6615 km²) encompasses the municipalities of Soure and Cachoeira do Arari. Bryophytes were collected from the 10th to the 16th of January, 2007, during random visits along existing trails or during the forging of new trails, from all possible types of vegetation, regardless of the type of substrate. The ecosystems visited in the study area were capoeira (secondary vegetation, growing on land that has been burned or cleared), teso (vegetation growing on areas of land at an elevation slightly higher than the water line during flood season), floodplain forest, mangrove forests, cerrado (savanna) and natural grasslands (pure and mixed). In total, 11 families, 30 genera, and 67 species were recorded, of which 39 represented new records for the island. Cololejeunea panamensis G. Dauphin & Pocs represented a new record for South America; Microlejeuneasubulistipa Steph. represented a new record for the northern region of Brazil, and Cololejeuneaverwimpii Tixier and Mastigolejeuneainnovans (Spruce) Steph. represented new records for the state of Pará.

Resumo em Inglês:

The abundance and distribution of resources for pollinators modulate the reproduction of plants. This study attempted to determine whether and how the fruiting success of Tibouchina trichopoda flowers varies due to plant size, number of flowers produced, distance between individuals and cardinal orientation of the flowers. From July 2009 to February 2010, we conducted monthly evaluations of 21 plants in an area of regenerating forest within the Atlantic Forest biome, located near the municipality of Antonina, in southern Brazil. Floral density was monitored weekly. During the study period, the species bloomed twice: once during the cool, dry season, showing an extended flowering period with scattered flowering individuals; and once during the hot, rainy season, showing a brief flowering period with a high density of flowering individuals. Plant size was not found to influence fruiting success. There was greater production of flowers and fruits during the brief flowering period. The extent of the floral display positively affected the fruiting success of the flowers, the effect being greater when the density of flowers was low and tending to stabilize at higher densities. The northern-facing portions of tree crowns produced more flowers and therefore had greater fruiting success than did the southern-facing portions. However, the proportion of fruits produced per flower was the same.

Resumo em Inglês:

Syagrus romanzoffiana (Cham.) Glassm. is a species native to Brazil that is of ecological and aesthetic importance. This study aims to describe the biometric characteristics of S. romanzoffiana fruits and to assess the effects that treatments meant to overcome dormancy and partial drying have on seed germination. For biometric characterization, each repetition consisted of 50 fruits from eight clusters (total, 400 fruits). To evaluate methods for overcoming dormancy, seeds representative of populations were treated by perforation of the operculum; perforation of the operculum and immersion in water for 24 hours; cracking; exposure to fire for three minutes; and non-removal of fibers. There was also a control group. In a second experiment, seeds were partially dried. We determined the proportional moisture content of newly harvested seeds (20.2%) and dried them down to moisture contents of 15.5% and 12.7%. All seeds were subjected to a germination test at 30ºC. The fruits showed biometric variations, with an average of 21.7 mm in longitudinal diameter and 19.7 mm in polar diameter, and a fresh mass of 5.61 g, of which 59.29% was pulp. The highest germination rates and vigor to overcome dormancy occurred after the operculum was perforated and the seeds were soaked in water for 24 hours. The results of the partial drying treatments did not differ sufficiently to discourage dormancy in any significant manner.

Resumo em Inglês:

Distyly is a genetically controlled floral dimorphism, characterized by the reciprocal positioning of pin and thrum morphs, a heteromorphic incompatibility system and a balanced morph ratio (isoplethy). This study aimed to investigate the phenology, features of distyly, reproductive biology, and floral visitors of Psychotria goyazensis Mull. Arg. (Rubiaceae), an intramorph self-compatible species, in a tropical semideciduous forest in the municipality of Catalão, located in the state of Goiás, Brazil. The phenology was recorded for a sample of individuals, the floral morphology being described using fresh and fixed material. The incompatibility system was tested using controlled hand pollinations. Floral visitors were collected and identified. Blooming began in November 2009 and ended in April 2010. Fruits developed from December 2009 to March 2010. The population presented atypical distyly, because only plants with pin flowers were found. The intramorph and open pollinations set more fruits than did spontaneous self-pollinations. The main flower visitors were Systropus sp. (Diptera), as well as Hymenoptera and Lepidoptera species. Morphological variations in distyly can occur by breakdown/permutation of the gene that controls the polymorphism. However, some authors argue that, in Rubiaceae, genetic control of the incompatibility system can operate independently of the morphological factor, and species might respond in different ways to the same selective pressures.

Resumo em Inglês:

Few studies have adequately described the floristic and structural features of natural grasslands associated with shallow basalt soils in southern Brazil. This study was carried out on natural grazing land used for livestock production in the municipality of Santana do Livramento, in the Campanha region of the state of Rio Grande do Sul, Brazil. The aim of the study was to describe the floristic and structural diversity of the area. The floristic list obtained comprises 229 plant taxa from 40 botanical families, with a predominance of the families Poaceae (62), Asteraceae (28), Fabaceae (16) and Cyperaceae (12). The estimated diversity and evenness in the community were 3.00 and 0.874, respectively. Bare soil and rock outcrops accounted for 19.3% of the area, resulting in limited forage availability. Multivariate analysis revealed two well-defined groups among the sampling units. One group showed a high degree of internal aggregation, associated with deep soils, and was characterized by the presence of tussocks, whereas the other was less aggregate and was characterized by prostrate species growing on shallow soil. Ordination analysis indicated a gradient of moisture and of soil depth in the study area, resulting in different vegetation patterns. These patterns were analogous to the vegetation physiognomies described for Uruguayan grasslands. Overall, the grassland community studied is similar to others found throughout southern Brazil, although it harbors more winter forage species. In addition, the rare grass Paspalum indecorum Mez is locally dominant in some patches, behaving similarly to P. notatum Fl., a widespread grass that dominates extensive grassland areas in southern Brazil.

Resumo em Inglês:

To study forest composition and structure, as well as to facilitate management plans and monitoring programs, we conducted a phytosociological survey in the PE Caverna do Diabo State Park and the Quilombos do Médio Ribeira Environmentally Protected Area, both located within the state of São Paulo, Brazil. We analyzed 20 plots of 400 m² each, including only individuals with a circumference at breast height > 15 cm. We employed cluster analysis and ordination (principal component analysis and correspondence analysis), including species data and abiotic data. We evaluated 1051 individuals, belonging to 155 species in 48 families. Of those 155, 18 were threatened species, 33 were endemic species, and 92 (59.4%) were secondary species. The overall Shannon index was 4.524, one of the highest recorded for a dense rainforest in southeastern Brazil. We found that our sample plots fell into three blocks. The first was forest in which there had been human disturbance, showing low species richness, minimal density, and a small relative quantity of biomass. The second was undisturbed mature forest, showing a comparatively larger quantity of biomass. The third was mature forest in which there had been natural intermediate disturbance (dead trees), showing higher species richness and greater density. We identified various groups of species that could be used in monitoring these distinct forest conditions.

Resumo em Inglês:

In tropical forests with low seasonality, climatic variables generally exert a weak influence on the phenology of species. The seasonality of phenophases in closely related taxa can be controlled by phylogenetic constraints in such environments. In this study, our aim was to describe the phenology of Rubiaceae in the understory of the Atlantic Forest in the southern part of Bahia, Brazil, as well as to evaluate the seasonality and phenological synchrony of this family. For two years, we observed 90 individuals belonging to 13 species, in an area of 0.2 ha. Leaf flushing and leaf fall did not demonstrate any seasonality, were continuous for most species and correlated with few of the climatic variables. Flowering was seasonal and correlated positively with all climatic variables. Species exhibited seasonality for this phenophase with high flowering overlap among species of Psychotria, indicating an aggregated pattern for this genus. Fruiting was also seasonal and correlated with all the climatic variables, unripe fruit development peaking at the beginning of the season during which humidity is highest and fruit ripening peaking in the season during which humidity is slightly lower. The vegetative and flowering patterns observed in the study area are commonly seen in other tropical forests. The reproductive seasonality of this family can facilitate the attraction of biotic agents, as postulated in the facilitation hypothesis. Our results demonstrate that climatic variables influenced the phenological patterns observed here, although the high reproductive seasonality and interspecific synchrony, especially in congeneric species, raises the possibility that phylogenetic proximity plays a role in the pattern of the family Rubiaceae.

Resumo em Inglês:

We analyzed the floristics and phytosociology of three palm swamps in the municipality of Bela Vista de Goiás, located in the state of Goiás, Brazil, in the central part of the Brazilian savanna (Cerrado). The floristic surveys were conducted monthly from May 2008 to April 2009, and 310 species were recorded (seven bryophytes, 15 ferns and 288 angiosperms). Bryophytes belonged to five genera and five families; ferns belonged to nine genera and nine families; and angiosperms belonged to 134 genera and 45 families. The angiosperm families with the highest species richness were Poaceae, Cyperaceae, Asteraceae, Eriocaulaceae, Xyridaceae, Lentibulariaceae, Melastomataceae, Rubiaceae and Fabaceae. The palm swamps were divided into three zones of increasing humidity: edge, middle and core. The number of species was higher in the middle than at the edge and the core. The families with the highest cover values were Cyperaceae, Melastomataceae, Arecaceae and Poaceae. Although the palm swamps had been disturbed to varying degrees, those disturbances did not affect the flora in the middle or the core. Floristic similarity was high between these two zones within a given palm swamp and low between the edges of different palm swamps.

Resumo em Inglês:

Mistletoe can have a major impact on the fitness of the host plant. If there is more than one species of mistletoe on the same host tree, the overall impact might be amplified. We report the occurrence of more than one species of mistletoe on the same host tree. Although it is not a rule in the field, to our knowledge, there have been no studies of this topic. In most cases, two species of mistletoe were recorded on the same host tree, although we recorded three species of mistletoe on one occasion. This demonstrates that different species of mistletoe can be compatible with the same host species. Therefore, compatibility (structural and physiological) might be an important factor for the occurrence of mistletoe. Recent studies have shown that if the mistletoe does not "recognize" the host species, the deposited seeds will germinate but the haustorium will not penetrate the host branch. This is probably the primary mechanism in the establishment of more than one species of mistletoe on the same host, which can trigger a cascade of harmful effects for the host species.

Resumo em Inglês:

We report here the first occurrence of Bangiopsis subsimplex (Mont.) F.Schmitz (Rhodophyta) for the northeastern coast of Brazil. The specimen was isolated from a laboratory sample of mollusk shells collected in Baía de Todos os Santos (Bimbarras Island, Brazil) and was held in sterilized seawater (33 UPS) enriched with 25% Provasoli solution. In the American Atlantic region, B. subsimplex presents a northern distribution limit at French Guiana and a southern limit at São Paulo. We conclude that the distribution of B. subsimplex has expanded, since the species was once known only to the southeastern Brazil, specifically to São Paulo.