Scielo RSS <![CDATA[Acta Botanica Brasilica]]> vol. 32 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Scientometrical review of Dinoflagellate studies in Brazil]]> ABSTRACT Scientific production in developing countries is currently increasing, but there is still an unbalanced distribution of scientific production between developed and developing countries. With the need to elucidate disparities in scientific production, this paper aims to review publications on dinoflagellates in Brazil by discussing spatial and temporal trends. A search for papers referring to dinoflagellates was performed in the Scopus database up to the year of 2016. A total of 125 papers were found, but only 106 were selected according to established criteria. A linear regression was used to evaluate the increasing temporal trend in production and non-parametric ANOVA for comparisons among study categories. Dinoflagellate and toxic taxa-based publications have increased from 1990 to 2016 for Brazil, yet a discrepancy in performance with other countries is evident. There is a constant increase in the number of functional ecology studies focusing on toxin-producing species related to blooms. The spatial distribution of production in Brazil revealed that the Southeast and South regions are the most productive, where there more graduate programs and advanced research centers. Investments in this ecological subject are fundamental to the management of biodiversity, and a call for more equal resource distribution in developing countries is imperative. <![CDATA[DNA fingerprinting based on SSR amplification profiles for <em>Piper</em> species identification (Piperaceae)]]> ABSTRACT DNA fingerprinting based on SSR amplification profiles was applied to native species of Piper from the Atlantic Forest to compare the utility of this type of molecular marker with the morphological characters traditionally applied in Piper taxonomy and identification. Fifty-one SSR markers developed for four species of Piper native to Asia and Mesoamerica were applied to 16 species, together with 63 morphological characters, for species characterization. Molecular and morphological data were analysed by cluster analysis, followed by a cluster sharpness test and the construction of a heat map to visualize the association of characters with species groups. A multivariate regression tree determined the number of loci needed for species identification. Forty-five primers were transferable to at least four species. Molecular data were more efficient in detecting sharp groups than morphological data. Species groups delimited by a set of shared morphological characters were differentiated based on molecular data. The sixteen studied species could be separated by nine primers, demonstrating the cross-species transferability of SSR markers and the usefulness of DNA fingerprinting for both the delimitation and the identification of species of Piper. <![CDATA[Nomenclatural novelties in <em>Lessingianthus</em> (Asteraceae - Vernonieae): an extraordinary new species, a lectotypification, and a new combination from a resurrected synonym]]> ABSTRACT Lessingianthus spinifolius is here described and illustrated as a new species of the tribe Vernonieae (Asteraceae) from Chapada dos Veadeiros, State of Goiás, Brazil. The new species is thus far known only from the type locality. The characteristics that most differentiate L. spinifolius from congeners are: (i) leaf blade strongly revolute; and (ii) leaf blade with spines on the margins. The new species is similar to L. onopordioides due to both having a similarly shaped involucre and the involucre being eximbricate with lanceolate phyllaries. Taxonomic and ecological comments, a distribution map, conservation status assessment, and illustrations of the new species are provided. Additionally, Vernonia araneosa is resurrected from the synonymy of L. durus, and a new combination, L. araneosus based on V. araneosa, is proposed, a lectotype designated, and its affinities with L. durus discussed. <![CDATA[Palm species richness, latitudinal gradients, sampling effort, and deforestation in the Amazon region]]> ABSTRACT Palms are most diverse in warm and humid regions near the equator. Though palms remain relatively well conserved, they are under increasing pressure from deforestation. Here, we analyze patterns of palm species richness relative to latitudinal gradient, sampling effort, and deforestation in the Amazon, and compare patterns of richness and floristic similarity among Amazonian sub-regions. We built a database of 17,310 records for 177 species. The areas with the greatest richness were in the western, central and northeastern Amazon, principally at latitudes 0-5ºS. Species richness and the number of records were highly correlated (R2=0.76, P&lt;0.005). The highest rates of deforestation (&gt;2000 km2) were found in the southern and eastern Amazon of Brazil, which coincide with low richness and gaps in records. Similarity analyzes resulted in two groups of sub-regions: the first included the Amazon s.s., the Andes and the Guiana, while the second included the Plateau and Gurupi. We conclude that the highest species richness is at low latitudes, and observed richness is affected by sampling effort and is vulnerable to deforestation. Therefore, areas with low species richness, especially areas with data deficiency, need to be further studied for a better understanding of their patterns of diversity and richness. <![CDATA[New combinations and taxonomic notes for <em>Tarenaya</em> (Cleomaceae)]]> ABSTRACT Tarenaya clade includes 37 species based on phylogenetic relationships and on the stipular spine synapomorphy, however only 10 species thought to belong to the genus have had names established in Tarenaya. Besides the two new species are being described, we present 25 new combinations for the species and refine the typification of 13 species. Ten lectotypes and three neotypes are designated here. One generic synonym is also typified. <![CDATA[Expression analysis of cell wall assembly and remodelling-related genes in <em>Arabidopsis</em> roots subjected to boron stress and brassinosteroid at different developmental stages]]> ABSTRACT Plant cell walls are affected by many biotic and abiotic stress conditions. The aim of this study is to determine the effects of 24-Epibrassinolide (EBL) on some cell wall-related genes in root tissue of five- and ten-week-old Arabidopsis thaliana plants exposed to boron (B) deficiency (0 µM) or toxicity (3000 µM) at the transcriptional level. Expressions of the genes that encode cellulose synthase (CESA1, CESA4, CESA6 and CESA8), cellulose synthase-like (CSLB5), expansin (EXPA5, EXPA8 and EXPA14) and cell wall protein (SEB1) decreased under conditions of B deficiency and toxicity. EBL treatments, in general, led the expressions of these genes to reduce significantly. Expressions of xyloglucan endotransglucosylase/hydrolase genes (XTH21 and XTH23) changed only under conditions of B toxicity. Boron stress and/or EBL treatments caused different responses in expression of pectin methylesterase (PME2 and PME41) genes. As a result of B stress, the expression levels of investigated genes changed more in roots of five-week-old plants than in roots of ten-week-old plants. Results of the present study include new findings that support the ability of BRs to increase molecular aspects of tolerance to stress in plants. <![CDATA[Survival and development of reintroduced <em>Cattleya intermedia</em> plants related to abiotic factors and herbivory at the edge and in the interior of a forest fragment in South Brazil]]> ABSTRACT Biotic and abiotic factors, such as luminosity, temperature, air humidity, and herbivory, can affect the establishment of reintroduced plants in natural habitats. This study evaluated the effects of these factors on the survival and growth of Cattleya intermedia plants reintroduced into a forest fragment in South Brazil. Plants of C. intermedia were obtained from in vitro seed germination in asymbiotic culture. Eighty-eight plants were reintroduced at both the forest edge and forest interior. Plants with greater shoot heights and number of leaves and pseudobulbs suffered more damage from herbivores at the edge. There were no significant differences in morphometric parameters between damaged and non-damaged plants in the interior. Tenthecoris bicolor, Helionothrips errans, Ithomiola nepos, Molomea magna and Coleoptera larvae damaged C. intermedia. Luminosity was higher at the edge, while air humidity and temperature were the same in both environments. Herbivory associated with abiotic factors increased plant mortality in the interior, while abiotic factors were determinative of plant survival at the edge. Luminosity is important to the survival of reintroduced epiphytic orchids, and herbivory affects the success of reintroduction. <![CDATA[Unraveling algae and cyanobacteria biodiversity in bromeliad phytotelmata in different vegetation formations in Bahia State, Northeastern Brazil]]> ABSTRACT Knowledge of algal and cyanobacterial diversity of phytotelmata remains poorly-known, especially for bromeliads from different vegetation formations. We investigated the microalgae communities of four species of tank bromeliads from different vegetation formations in Bahia State, Northeast Brazil, highlighting the composition, richness and diversity of taxa. Sampling of water stored in bromeliads was carried out quarterly between 2014 and 2016, and abiotic variables and morphometric attributes of bromeliads were measured. A total of 89 taxa of algae and cyanobacteria were recorded for the four bromeliad species studied. The microalgae communities of the phytotelmata varied among vegetation formations, with one tank bromeliad, Alcantarea nahoumii, with more complex architecture (higher number of leaves and thus more cavities), being distinguished by its high species richness (73 taxa). The bromeliads exhibited little similarity in species composition, with only one species (Phacus polytrophos) occurring in all four species. Throughout the entire sampling period, classes with higher species richness, especially due to A. nahoumii, were Zygnematophyceae, Cyanophyceae and Chlorophyceae, which accounted for about 80 % of all species inventoried. Our results contribute to the knowledge of microalga communities of bromeliad phytotelmata in Brazil with regard to species richness and composition, as well as significant environmental characteristics. <![CDATA[Together yet separate: variation in soil chemistry determines differences in the arboreal-shrub structure of two contiguous rupestrian environments]]> ABSTRACT Rupestrian landscapes are characterized by vegetation mosaics comprised of different plant communities and strongly linked to environmental filters. These environments are nutrient-impoverished, and possess water retention deficits and high solar exposure. This study aimed to determine whether chemical properties of the soil shape the arboreal-shrub vegetation structure in two neighboring habitats; a rupestrian cerrado and a rupestrian grassland. We hypothesized that the habitat with higher soil chemical properties would have higher parameters for vegetation structure, and different species composition. We expected higher chemical properties of the soil to favor a greater variety of plant life-forms. A total of 1349 individuals of 85 species belonging to 24 families were recorded; 1141 individuals (65 species) in the rupestrian cerrado, and 208 individuals (20 species) in the rupestrian grassland. Overall, Asteraceae, Fabaceae and Melastomataceae had greater species richness in both areas. Both habitats floristic composition was strongly influenced by differences in soil chemistry. In the cerrado, species richness, composition, soil nutrient availability and acidity were greater than in the grassland. We demonstrated that variation in soil chemistry influences plant species richness and composition, and structural complexity of vegetation, in both contiguous rupestrian environments, and that soil chemistry heterogeneity yields different plant life-form strategies. <![CDATA[Potential effects of mechanically removing macrophytes on the phytoplankton community of a subtropical reservoir]]> ABSTRACT Intensive growth of aquatic macrophytes interferes with water quality and ecosystem dynamics worldwide. Although mechanically removing macrophytes is the most commonly used method for their eradication, it can also cause undesirable disturbances in aquatic reservoir communities. We performed laboratory incubations of phytoplankton sampled before and after macrophytes were mechanically removed from the Piraquara II reservoir, South Brazil. We analyzed changes in growth and composition of the main phytoplankton groups with respect to nutrient shifting. Prior to removing the macrophytes, the phytoplankton community was dominated by low cell abundances of diatoms and flagellates. In contrast, growth rates of cyanobacteria (mainly Cylindrospermopsis raciborskii, Pseudanabaena sp., and Geitlerinema sp.) and of colonial chlorophytes were favored after macrophyte removal, while the abundances of diatoms and flagellates decreased. Our results suggest that removing macrophytes causes dramatic changes in phytoplankton composition and biomass and selects for toxigenic species of cyanobacteria. These changes were probably associated with the disturbance caused by removing the macrophytes, which immediately created new environmental conditions prone to species competition. These findings indicate that the use of mechanical techniques to manage macrophytes should be carefully considered, along with monitoring of harmful species and changes of limnological parameters. <![CDATA[Changes in the taxonomic structure of periphytic algae on a free-floating macrophyte (<em>Utricularia foliosa</em> L.) in relation to macrophyte richness over seasons]]> ABSTRACT Periphyton has a strong relationship with aquatic macrophytes, which are key components of spatial heterogeneity in the littoral zone. We evaluated the relationship between the community structure of periphytic algae on Utricularia foliosa and macrophyte richness and coverage and limnological variables in a shallow reservoir. Water sampling for physical, chemical and biological analyses was performed at sites with contrasting macrophyte coverage and richness in each of the four main seasons of the year. Periphytic algae were evaluated for density and species composition. High densities of diatoms and filamentous cyanobacteria in the periphyton were observed at sites with high macrophyte coverage and richness, while high abundances of flagellates of Chrysophyceae and Chlorophyceae were found at sites with low macrophyte richness. Light and nutrient availability were determining factors of the temporal variability of the periphytic algae community. We concluded that the interaction between seasonality and spatial heterogeneity (macrophyte community structure and limnological variables), explained the variability in species composition and algal density of the periphyton. Therefore, seasonality and spatial heterogeneity acted as determining factors for periphyton structure on a free-floating macrophyte with high structural complexity. <![CDATA[The presence of Fabaceae in the pollen profile of propolis produced in northeastern Brazil]]> ABSTRACT Propolis is a resin-like substance composed mainly of resin, wax, essential oils, pollen grains and specific plant parts collected by the honeybee Apis mellifera, which mixes them with fluids they secrete. The components and chemical properties of propolis vary among regions. Therefore, in order assess variation in the botanical composition of propolis, 26 samples of propolis (brown, red, and green) produced throughout northeastern Brazil were analyzed by acetolysis specifically adapted for propolis. In total, 196 pollen types were recorded, representing 123 genera and 47 families, with types of Fabaceae and Rubiaceae being present in 100 % of the samples. Fabaceae was the richest group with 49 pollen types, followed by Malvaceae (10 types), particularly related to the high frequencies of Mimosa pudica (84.62 %), Alternanthera, Borreria verticillata, and Myrcia (80.77 %). Remarkably, 34 % of the pollen types with frequencies above 50 % belonged to Fabaceae, even though this family has been traditionally regarded as less important with regard to propolis production, given that most of its included taxa are classified as polliniferous or nectariferous. Similarity analyses revealed clusters of propolis samples that share pollen types associated with plants having apiculture potential. <![CDATA[UV-B radiation as an elicitor of secondary metabolite production in plants of the genus <em>Alternanthera</em>]]> ABSTRACT Ultraviolet B radiation has been described as a potential elicitor agent of the synthesis of secondary metabolites in plants. Thus, the present study aimed to investigate the production of betalains and total flavonoids, as well as the antioxidant activity, of Alternanthera sessilis, A. brasiliana, A. tenella and A. philoxeroides exposed to different periods of UV-B radiation (280-315 nm). Plants of these four species were exposed to UV-B radiation for 0, 2, 4, 6, and 8 hours, which amounts to 0, 10, 20, 30, and 40 J cm−2 of radiation, respectively. Significant increases in betacyanin and betaxanthin levels were observed in A. sessilis and A. brasiliana during the period of UV-B exposure, while no differences were observed for the others species. The highest estimated flavonoid levels were for A. sessilis exposed to UV-B radiation for 8 h, followed by a 24-h recovery period. In conclusion, the action of UV-B radiation as an inducer of defence responses in plants is influenced by increasing exposure periods followed by a recovery period. Both increase the levels of these composts, yet this increase is different among the four Alternanthera species, having a greater influence on the species A. sessilis and A. brasiliana. <![CDATA[Phenotypic similarity between fruits of <em>Gevuina avellana</em> (Proteaceae) and wasp-induced galls of <em>Nothofagus dombeyi</em> (Nothofagaceae) does not protect fruits from predation by rodents]]> ABSTRACT Fruits of Gevuina avellana (Proteaceae) seem to mimic wasp-induced galls of Nothofagus dombeyi (Nothofagaceae) to escape predation by rodents, which may change both spatially and temporarily. The objective of this study was to evaluate the similarity between the fruits of G. avellana and the galls of N. dombeyi and to determine if this similarity protects fruits from predation by rodents in a disturbed temperate forest. We evaluated: i) the similarity between fruits and galls by measuring length, diameter, weight and color; and ii) the effects of galls on fruit predation by offering them to rodents in varying proportions, in a forest and a meadow, over two years. Fruits and galls showed similar phenotypes but fruits were more consumed than galls, even at low fruit frequencies, suggesting that their similarities are not due to mimicry. Fruits escaped predation more in the meadow than in the forest, particularly during the second year, thus indicating spatio-temporal variability in the phenomenon. The similarity between fruits and galls seems to be the result of phylogenetic and/or developmental constraints, rather than the result of a Darwinian coevolutionary pathway mediated by rodents. However, mimicry may happen with other dry-fruited plants inhabiting deforested habitats, which encourages further studies. <![CDATA[Management priorities for exotic plants in an urban Atlantic Forest reserve]]> ABSTRACT Biological diversity is directly affected by alien species, even though the diagnosed impacts vary with scale. Early identification of the invasion of natural patches is essential for effective conservation actions. We aimed to determine the exotic plant species present inside Fontes do Ipiranga State Park (PEFI), an urban protected area located in the city of São Paulo, Brazil, and their relative proportions of occurrence in the native forest. Our goal was to use these data to assess their invasion status according to specific literature and to define management priorities for them. Therefore, we surveyed the presence of exotic plants within the canopy layer and understory of three native forest areas with different levels of disturbance. We found ten exotic plant species. The species found in both strata (60 %) were considered non-dominant ruderal. We assessed the density:coverage ratio to try to distinguish groups of priority, and found Livistona chinensis, Archontophoenix cunninghamiana, and Syzygium jambos to be classified as high priority for management. The early stage of the invasion process at PEFI indicates it is an area of high conservation value, and so we provide recommendations for management priorities prior to severe changes in the composition of the natural plant community. <![CDATA[Fruit of <em>Lepidaploa</em> (Cass.) Cass. (Vernonieae, Asteraceae): anatomy and taxonomic implications]]> ABSTRACT Lepidaploa is a taxonomically complex genus of Vernonieae, which is difficult to delimit morphologically due to vegetative and reproductive characters that overlap with Chrysolaena and Lessingianthus. Anatomical studies of cypselae are taxonomically useful for delimiting subtribes, genera and species of Asteraceae, and especially within Astereae and Eupatorieae. Given the importance of cypselae to the taxonomy of tribes of Asteraceae, we searched for morphological patterns among the species of Lepidaploa. Using light microscopy, we analyzed fruits of 21 species of Lepidaploa to evaluate the taxonomic position of the genus and species of questionable placement in the group. Our results showed that the morphologies of the cypselae of species of Lepidaploa are homogeneous and similar to other species of Vernonieae. However, pappus vascularization and the number of mesocarp layers could be useful for differentiating the sister groups Chrysolaena, Lepidaploa and Lessingianthus, which present similar macro- and micro-morphological, palynological and chromosomal characters. Also, the presence of glandular trichomes and idioblasts in the cypsela, and lignified cells in the carpopodium exocarp, can be used to separate closely related species. <![CDATA[Mycological Diversity Description I]]> ABSTRACT Here, Quambalaria fabacearum and Neopestalotiopsis brasiliensis are introduced as new species from Brazil, isolated as endophyte from Mimosa tenuiflora and causing post-harvest rot disease on fruits of Psidium guajava, respectively. Diaporthe inconspicua is emended to include a more detailed morphological description. Neopestalotiopsis egyptiaca is reported as new to the Americas and as causing post-harvest rot disease on fruits of Psidium guajava, while Umbelopsis isabellina is reported as endophyte. <![CDATA[A methodological proposal for the recovery of palynomorphs from snow and ice samples]]> ABSTRACT The procedures for a set of techniques to recover grains of pollen 26 and spores from liquid samples are described. Liquefied samples of matrices, such as melting lakes, snow and ice, can provide a record of climatic and environmental events at different geographic and temporal scales. The need for standardization of techniques was demonstrated in research carried out with matrices of snow and water of thawing lakes and snow collected on King George and Joinville islands (Antarctica). The use of the methods described can permit increased rescue of palynomorphs from liquid matrices, thereby adding greater reliability to palynological data and its use as a biotracer of environmental events. Methods of sieving and centrifugation were tested, and sieving proved more efficient for the matrices analyzed. <![CDATA[Plant architecture influences gall abundance in a tropical montane plant species]]> ABSTRACT Sessile and host-specific herbivores, such as gall-inducing insects, are usually patchily distributed within the populations of their host plants, and it has been suggested that both inter- and intra-plant variation affect gall abundance, distribution and survivorship. Variation in plant traits, such as size and architecture, has been previously demonstrated as a determinant of gall distribution. We examined the influence of architectural complexity of the tropical plant Galianthe brasiliensis (Rubiaceae) on the abundance of the stem-galler Lopesia sp. (Diptera, Cecidomyiidae) along an elevation gradient where both insect and plant were distributed. A total of 120 plants were sampled along the gradient and more than 580 galls were counted, while plant architectural complexity was determined by a combination of height and branch ramification. Increased elevation did not influence plant complexity nor gall abundance (both P&gt;0.05), but plant architectural complexity explained more than 60% of the variation in gall abundance along the gradient (R2=0.62, P&lt;0.001). We suggest that the greater availability of meristematic tissues in more architecturally complex plants explains the results found, as this is a key resource for gall occurrence and establishment.