Scielo RSS <![CDATA[Acta Botanica Brasilica]]> vol. 28 num. 3 lang. <![CDATA[SciELO Logo]]> <link></link> <description>Passiflora subg. Decaloba supersect. Decaloba sect. Xerogona (Passifloraceae) is a tropical and subtropical group comprising 14 species that occur in tropical biomes throughout Latin America, including the Atlantic Forest. The section Xerogona comprises herbaceous vines characterized by a lack of petiole glands on their leaves, of bracts and of ocelli on their leaf blades, as well as by their capsular fruits. We analyzed the phylogeny on the basis of morphological characters (including pollen characters) and molecular data. The inferred phylogeny was used in order to characterize, circumscribe and delimit the section and the species. We examined the phylogenetic relationships among the species, evaluating the circumscription of the section on the basis of the trnL-trnF intergenic spacer region of chloroplast DNA and the internal transcribed spacer region of nuclear ribosomal DNA. We constructed phylogenetic trees on the basis of the morphological and molecular data. We found that P. subg. Decaloba supersect. Decaloba sect. Xerogona appears to be monophyletic only in the molecular analyses. The phylogenetic analyses performed here also indicated that P. subg. Decaloba is monophyletic.</description> </item> <item> <title/> <link></link> <description>The ability of plants to generate fertile offspring is influenced by morpho-physiological and ecological factors. Hence, reproductive success is directly linked to factors affecting quantity and quality of their progeny. In the Cerrado (savanna) of Brazil, the Vochysiaceae is a widely distributed and ecologically important family. Factors affecting pre-dispersal seed predation and abortion were studied for populations of Callisthene fasciculata, C. major, Qualea multiflora and Q. parviflora. To characterize differences between genera, as well as among species, study areas, and individuals, we quantified pre-dispersal seed predation and abortion. Differences of seed abortion among the species were related to intrinsic reproductive features and not to area or other factors. In contrast, seed predation varied not only among species but also among areas and among individuals. Only C. fasciculata showed no seed predation. In Qualea species, insect predators were found inside the seeds; whereas predators of Callisthene species were outside seeds. In both genera, seed abortion correlated negatively with area size, as did pre-dispersal seed predation, which suggest seed abortion may be a counter-measure to avoid predation. Although seed abortion and predation reduced the progenies of the studied species, seed production did not differ from other Cerrado species.</description> </item> <item> <title/> <link></link> <description>Orchidaceae is one of the largest and most diverse plant families in the world. The number of floristic studies of this family in Rio de Janeiro state, Brazil, has increased significantly in recent years. However, only a few such studies have been conducted in areas of restinga vegetation and none of those have examined the similarity, in terms of orchid diversity, among such areas. The present study sought to improve our knowledge of the Orchidaceae diversity occurring in Grumari restinga, as well to compare the diversity of orchids among Grumari and other restinga areas using cluster analysis. We found 15 genera and 19 species. Cluster analysis demonstrated that restingas located on islands are considerably different from those on the mainland, and no relationship was observed between floristic similarity and geographical proximity. As such, the present study shows that each area of restinga hosts different Orchidaceae species, demonstrating the importance of preserving this threatened ecosystem and this plant group.</description> </item> <item> <title/> <link></link> <description>This paper describes the vegetative and reproductive morphology of Cabombaceae species in Brazil, discussing its strategies for survival in an aquatic habitat. Through studies in the field, in cultivation and in the herbarium, we examined the following species: Cabomba aquatica, C. caroliniana, C. furcata and C. haynesii. In cultivation, only C. aquatica, C. furcata and C. haynesii produced flowers. In those three species, the flowers opened during the day on two consecutive days, submerging during the night, although the stigmata of the first two were receptive only on the first day, their anthers dehiscing on the following day. The flowers of C. haynesii remained unreceptive on the first day of anthesis, the stigmata and anthers maturing only on the second day, at different times. Fruit developed when the flowers were submerged. The data provided here are useful for the identification of these species, as well as laying the groundwork for future taxonomic and ecological studies.</description> </item> <item> <title/> <link></link> <description>The genus Menisporopsis S. Hughes is characterized by synnematous conidiomata around a central seta, phialidic conidiogenous cells and falcate to lunate 0- to 1-septate conidia with terminal setulae. Currently, nine species are included in the genus. In the course of investigating conidial fungi associated with decaying plant material in the semi-arid region of Brazil, we identified five Menisporopsis species: M. kobensis Matsush.; M. novae-zelandiae S. Hughes & Kendr.; M. pirozynskii Varghese & Rao; M. profusa Piroz. & Hodges; and M. theobromae S. Hughes. Ours represents only the second record of M. kobensis for the world. We present descriptions, comments, geographic distributions and illustrations for all five species, as well as a key to the recognized species.</description> </item> <item> <title/> <link></link> <description>This study evaluated the effect of salt stress on the growth of Lippia gracilis Schauer, a species native to the caatinga (shrublands) of Brazil and rich in essential oils, as well as on the quality of its oil. We exposed individuals of L. gracilis to NaCl, in the following concentrations, for a period of 40 days: 25 mM; 50 mM; 75 mM; and 100 mM. An additional group of plants was not exposed to NaCl (controls). Data were collected on days 20 and 40. We evaluated relative growth rate; shoot and root dry weight; relative water content; proline concentration in leaves; and chemical composition of the essential oil. At all concentrations, NaCl reduced the relative growth rate in comparison with that observed for the controls. No significant difference in relative water content was observed among treatments. In all treatments, the proline concentration in leaves was highest on day 40. Salt stress did not affect the yield or the concentrations of the constituents of the essential oil of L. gracilis, carvacrol and thymol showing the highest concentrations in all treatments.</description> </item> <item> <title/> <link></link> <description>We analyzed the pollen grains of 11 species within the subfamily Bombacoideae. The pollen grains were acetolyzed, after which they were analyzed and photographed under light microscopy. Unacetolyzed pollen grains were analyzed and photomicrographed under scanning electron microscopy. We studied pollen characters such as shape, size, exine ornamentation and aperture type. The species were separated by a pollen key, which considers the presence or absence of "calotte" in the pollen grains. This attribute separated Ceiba and Eriotheca from the other genera. Some species are differentiated by specific characters: in Bombacopsis glabra and B. stenopetala, the sexine is rugulate or "vermiculate" with isolated pilate elements; in B. calophylla, the pollen grains are sinu-aperturate; Ceiba speciosa show atypical, duplicolumellate sexine; C. erianthos is the only species with 5-colporate pollen grains and a pentagonal amb; in Pachira aquatica the reticulum has muri with spiculaspinulose muri ("reticulum cristate"). The variation in the pollen morphology confirms the eurypalynous status of the genera studied here.</description> </item> <item> <title/> <link></link> <description>The temporal expression of gene sor1 and the inhibitory effect of Sorghum bicolor L. Moench against weeds were studied by semiquantitative polymerase chain reaction and intercropping management, respectively. To quantify sor1 expression, seeds were sown in pots and RNA was collected from the roots at 5, 10, 15, 20 and 30 days after emergence (DAE). In the inhibition assay, cotton and three weeds were evaluated during single cropping and during intercropping with S. bicolor. The assay was completely randomized, with eight replications. We found early expression of sor1 in most S. bicolor accessions by 5 DAE, and a gradual reduction thereafter. Only one of the accessions showed sor1 expression up to 30 DAE. In the inhibition assay, the most significant effects were related to the dry matter production (shoots and roots) of the weeds Cenchrus echinatus and Cynodon dactylon. The intercropping of cotton and S. bicolor had no apparent deleterious effects.</description> </item> <item> <title/> <link></link> <description>Karyotype studies were performed in 18 populations of eight Helichrysum species in Iran. Those species showed chromosome numbers of 2n = 2x = 14; 2n = 4x = 24, 28 and 32; 2n = 6x = 36; 2n = 7x = 42; 2n = 8x = 48; 2n = 9x = 54; and 2n = 10x = 60. The chromosome numbers of H. davisianum, H. globiferum, H. leucocephalum and H. oocephalum are reported here for the first time. New ploidy levels are reported for H. oligocephalum (2n = 4x = 24) and H. plicatum (2n = 4x = 32). The chromosomes were metacentric and submetacentric. An ANOVA among H. globiferum and H. leucocephalum populations showed significant differences for the coefficient of variation for chromosome size, total form percentage and the asymmetry indices, indicating that changes in the chromosome structure of Helichrysum species occurred during their diversification. Significant positive correlations among the species and populations studied, in terms of the total chromosome length, lengths of the short arms and lengths of the long arms, indicate that these karyotypic features change simultaneously during speciation events. The genome sizes of Helichrysum species are reported here for first time. The 2C DNA content ranged from 8.13 pg (in H. rubicundum) to 18.4 pg (in H. leucocephalum and H. davisianum). We found that C-value correlated significantly with ploidy level, total chromosome length, lengths of the long arms and lengths of the short arms (p<0.05), indicating that changes in chromosome structure are accompanied by changes in DNA content.</description> </item> <item> <title/> <link></link> <description>In the course of preparing the taxonomic revision of the Rhamnaceae of Brazil for the Catalogue of Plants and Fungi of Brazil, several problems related to typification were detected. Taxonomic observations and nomenclatural notes are here reported based on the analysis of type material, as well as classic and recent collections, in 63 herbaria in Brazil and abroad, together with analyses of virtual herbaria. Types were sought, the majority of which were located and studied. Eleven synonymies, 37 lectotypes and one neotype are designated and defined for seven genera in the family.</description> </item> <item> <title/> <link></link> <description>Accurate knowledge of floristic composition is crucial when planning and designing research projects and public policies. In this study, our goal was to assess tree sampling accuracy and to identify sites with higher concentrations of rare tree species, as well as those with the highest tree species richness, in the state of Santa Catarina, Brazil. We determined sampling accuracy using the first-order jackknife and Chao 2 estimators, calculated the number of rare species (singletons and doubletons) and applied sampled-based rarefaction. We found that sample accuracy (estimated vs. observed values) was over 90% for the state as a whole, the best estimates having been obtained for the areas of rain forest (first-order jackknife: 91%; Chao 2: 95%). Of the tree species identified, 16.6% were considered rare in the state and only 4% were found in all forest types. Among the various forest types, semideciduous forests showed the highest proportions of rare tree species. Tree species richness was highest in the rain forests and lowest in the dwarf cloud forests. Our results make an important contribution to the conservation of tree species within one of the "hottest" biodiversity hotspots in the world.</description> </item> <item> <title/> <link></link> <description>We documented litter production and seed rain in fragments of semideciduous forest (SDF) in the western part of the state of Paraná, Brazil: a late successional fragment (LF); an early successional fragment (EF); and a reforested late successional fragment (RLF). In each fragment, we established three permanent plots with four litter traps each, corresponding to 12 litter traps per fragment. Botanical material was collected monthly between June 2011 and May 2012. We sorted the material by category: leaves; branches; reproductive structures; and miscellaneous. We analyzed the seed rain using the reproductive structures. Annual production was highest (11,560 kg.ha-1) in the LF, followed by the RLF, with 9330 kg.ha-1, and the EF, with 7838 kg.ha-1. The RLF yielded 7167 diaspores, from 33 species, compared with 4751 diaspores, from 38 species, for the EF; in both fragments, pioneer and anemochorous species predominated. The LF yielded 2173 diaspores, from 49 species, among which late secondary and climax species with zoochorous dispersal predominated. We observed asynchrony in the frequency of diaspore production of trees and lianas. Our data describe the dynamics of plant assemblages in SDF fragments and provide information on successional stages, dispersion syndromes, patterns of asynchrony, deciduousness, reproductive periods, and resource availability for frugivores.</description> </item> <item> <title/> <link></link> <description>The fern genus Elaphoglossum has received a great deal of attention in Brazil over the last two centuries. Nevertheless, many of the early names remain inadequately typified. In this paper, the nomenclature of some Brazilian species of Elaphoglossum sect. Polytrichia is discussed under the rules and recommendations of the International Code of Nomenclature for algae, fungi, and plants. Lectotypes are designated for the following names: Acrostichum amplissimum Fée; A. apodum Kaulf. var. sprucei Baker; A. glaziovii Fée; A. lindbergii Mett. ex Kuhn; A. prestonii Baker; Elaphoglossum spannagelii Rosenst.; and Elaphoglossum ulei H. Christ. Most of these types were collected in Brazil during the 19th century and are now preserved in several European herbaria.</description> </item> <item> <title/> <link></link> <description>We assessed the allelopathic effects of the aqueous extract of Sonchus oleraceus dry shoots on the germination and seedling growth of Trifolium alexandrinum, three weed species (Brassica nigra, Chenopodium murale and Melilotus indicus) and S. oleraceus itself. We assayed four different concentrations of the aqueous extract (w v-1): 1%, 2%, 3% and 4%. To determine whether the effects of the extract were attributable to the presence of allelopathic compounds, its osmotic potential or both, we prepared concentrations of polyethylene glycol (PEG) with osmotic potentials equivalent to those of the aqueous extract. All concentrations of the plant extract completely inhibited the germination and seedling growth of C. murale. The lowest concentration of the plant extract partially inhibited germination and seedling growth of B. nigra, M. indicus and S. oleraceus, whereas the higher concentrations inhibited those parameters completely. The germination of T. alexandrinum was not affected by the aqueous extract at 1% or 2%. In general, the aqueous extracts were more effective in inhibiting seed germination and seedling growth than were the PEG solutions. Phytochemical analyses revealed that phenols and alkaloids were the most abundant compounds in S. oleraceus dry matter. Our results suggest that the aqueous extract of S. oleraceus has an allelopathic effect on some weeds, and its usefulness as a bioherbicide therefore merits further study.</description> </item> <item> <title/> <link></link> <description>Here, we investigated the population structure of the exotic palm Roystonea oleracea in a swamp on an island within the Atlantic Forest Biome, evaluating its influence on the seedling recruitment of other plant species. The population structure was analyzed in six 4 × 30 m plots, within which we categorized all individuals by ontogenetic stage. The influence of R. oleracea on the seedling recruitment of other plant species was evaluated in 2 × 2 m plots established beneath palm crowns and in adjacent areas without palms. We recorded 53 R. oleracea individuals. The majority (56.6%) of the R. oleracea population was composed of immature adults, followed by mature adults. The density, richness and diversity of seedling species differed significantly between areas beneath and away from palms, the values being lower beneath R. oleracea crowns. Our results indicate that R. oleracea recruitment does not require human intervention, the number of reproductive individuals characterizing successful naturalization. This underscores the need for management policies aimed at palm eradication in order to avoid reductions in biodiversity.</description> </item> <item> <title/> <link></link> <description>The evaluation of the post-germination phases of plants allows the recognition of transitional structures that support the relationships among taxa and their establishment. Together with fruit and seeds, seedlings and saplings provide useful characters for identifying many species. This study aimed to describe and characterize the morphology of the fruits, seeds, seedlings and saplings of Macrolobium acaciifolium, M. bifolium and M. pendulum, as well as to evaluate the ecological, taxonomic and phylogenetic value of the structures identified. In this work, the seeds were sown in plastic trays with sterilized sand and sawdust, without pre-germination treatment. The fruits of the three species are woody legumes, dehiscent fruit or indehiscent fruit. The seeds have seed coats with or without venation and variable embryos, with plumules differing among the three species; this trait can be helpful in distinguishing among the species studied. The seedlings are of the cryptocotylar-hypogeal-reserve or phanerocotylar-epigeal-reserve type. Macrolobium bifolium and M. pendulum are similar species, differing in only a few characters. These characters have taxonomic value and aid species identification. The characteristics of M. pendulum are described here for the first time.</description> </item> <item> <title/> <link></link> <description>Dimorphandra wilsonii Rizzini is a rare species. Although cited as endemic to the Brazilian state of Minas Gerais, it has been recorded only for the municipalities of Paraopeba and Caetanópolis and therefore has not been extensively studied. This long-term, intensive survey, conducted from 2004 to 2012 in the central region of the state, was aimed at assessing its distribution, describing its habitat, and verifying its endemism, as well as assessing threats and determining its conservation status. Given the considerable size of the area to be studied and the difficulty of locating individuals of the species, we adopted popular participation as a complementary tool and we employed spatial distribution modeling. Communities were mobilized through the dissemination of print materials, and interviews were conducted. We visited 74 municipalities and addressed 900 people in search of this species. We found that D. wilsonii is endemic to the cerrado (savanna) and Atlantic Forest in the central region of Minas Gerais, occurring in 16 municipalities. Is not present in any fully protected conservation area, and its population (fewer than 250 individuals) is declining due to habitat destruction, caused mainly by agricultural/livestock and urban expansion, and its conservation status is "critically endangered".</description> </item> <item> <title/> <link></link> <description>The present study was carried out on three trails, each presenting a different degree of disturbance, within the Pau-Ferro Forest Environmentally Protected Area, a 600 ha area of highland forest located in the municipality of Areia (06°58'12"S; 35°42'15"W; elevation, 400-600 m), in the state of Paraíba, Brazil. In 2005, we analyzed the species richness, abundance, constancy and phenology of myxomycetes over seven consecutive months (rainy and dry seasons) in five types of microhabitats: dead tree trunks, the bark of living trees, basidiomata, ground litter and aerial litter. A total of 753 specimens of 48 species were obtained from the trails known as Flores (4 km), Boa Vista (3 km) and Cumbe (700 m). The Sørensen similarity coefficient revealed that the three trails are similar. The most constant and abundant species were Hemitrichia calyculata, H. serpula, Arcyria cinerea, A. denudata and Ceratiomyxa fruticulosa. Although myxomycetes sporulate throughout the year, some species have well-defined sporulation seasons. In terms of the constancy and abundance of species, Trichiaceae is the most important family in the rain forest studied, which is representative of the highland forests of northeastern Brazil.</description> </item> <item> <title/> <link></link> <description>We analyzed the community structure of an upper montane cloud forest (elevation, 1900 m) in the Serra da Mantiqueira Mountain Range, in the state of Minas Gerais, Brazil. Our objective was to determine the comparative tree species richness and floristic diversity within this forest, which is at one of the higher elevations in the range, in relation to surrounding forests that are at lower elevations, adjusting for elevational gradients. Within 15 permanent plots (40 × 10 m each), we tagged all tree individuals with a diameter at breast height > 5 cm, registering their height and diameter. To compare the study area with neighboring cloud forests, we used the Sørensen similarity coefficient and phytosociological parameters. We sampled 1250 individuals distributed among 89 species, 55 genera, and 34 families. Canonical correspondence analysis revealed no gradients related to the vegetation or soil. We found that tree species richness and diversity were high in the study area. There was structural and floristic heterogeneity among the communities evaluated, underscoring the importance of conservation of these high-elevation ecosystems, which are so unique and irreplaceable.</description> </item> <item> <title/> <link></link> <description>The waterlogging of soils creates selective environments for plant species. The frequency and duration of flooding influence the responses to ecological processes, determining the structure and floristic composition of vegetation formations. We investigated the relationship between floristic composition and environmental heterogeneity of native field, one physiognomic type found interspersed with semideciduous forest in the plains in the northern part of the state of Espírito Santo, Brazil, which is characterized by varying degrees of waterlogging. Our results indicate that the differentiation of physiognomic types of native field is related to the frequency and duration of waterlogging to which each is subjected, resulting in a somewhat shared flora, dominated by phanerophytes. Flooding was also found to account for differences between the areas analyzed in terms of the soil pH, which ranged from strongly acid to extremely acid. The geographic proximity between the native field studied and areas of muçununga (or mussununga, a coastal forest ecosystem associated with the Atlantic Forest) did not increase the floristic similarity between the two.</description> </item> <item> <title/> <link></link> <description>This study tested the ecological apparency hypothesis in the community of Barroquinha, in the municipality of Lagoa, Paraíba State, Brazil. We used the Use Value (UV) by testing the information obtained through three types of calculations: UVgeneral, UVcurrent, and UVpotential. The botanical sampling was conducted in two areas of the community (Preserved - A1; Degraded - A2), and interviews were carried out with 66 people, who signed a Free and Transparent Consent form, required by the Research Ethics Committee. The Spearman's correlation test was performed to relate phytosociological data to ethnobotanical data. We used the Pearson Correlation to test the correlation between genders and the Use Values (UVs). Fifteen useful species were recorded in A1 and 16 species in A2. Positive correlations were found in both areas between species and the phytosociological data: in A1 between UVcurrent with basal area and dominance (p < 0.05) and in A2 between UVgeneral and UVcurrent with all parameters (p < 0.05). Only the forage category showed a positive correlation in A1 between UVpotential and density and frequency (p < 0.05). In A2, the fuel category was correlated with UVcurrent and basal area and dominance (p < 0.05). There was positive correlation between UVgeneral/UVcurrent, UVgeneral/UVpotential, UVcurrent/UVpotential (p < 0.0001). Men and women considered the same species as the most important (p < 0.0001). According to the results of this study, we can conclude that ecological apparency best explains the relationship between use and availability of species used for timber.</description> </item> <item> <title/> <link></link> <description>The aim of this study was to characterize the wood of Aniba species from the Brazilian Amazon, on the basis of specimens in the wood collection of the Herbarium of the Museu Paraense Emílio Goeldi, in the city of Belém, Brazil. The species were found to present a homogeneous structure in the secondary xylem, as defined by the location of oil cells; the presence of tyloses and crystals; and singularities of the radial and axial parenchyma.</description> </item> </channel> </rss> <!--transformed by PHP 11:12:42 20-12-2014-->