Scielo RSS <![CDATA[Acta Botanica Brasilica]]> vol. 33 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Sustainable production of bioactive alkaloids in <em>Psychotria</em> L. of southern Brazil: propagation and elicitation strategies]]> ABSTRACT Psychotria is the largest genus in Rubiaceae. South American species of the genus are promising sources of natural products, mostly due to bioactive monoterpene indole alkaloids they accumulate. These alkaloids can have analgesic, antimutagenic, and antioxidant activities in different experimental models, among other pharmacological properties of interest. Propagation of genotypes with relevant pharmaceutical interest is important for obtaining natural products in a sustainable and standardized fashion. Besides the clonal propagation of elite individuals, the alkaloid content of Psychotria spp. can also be increased by applying moderate stressors or stress-signaling molecules. This review explores advances in research on methods for plant propagation and elicitation techniques for obtaining bioactive alkaloids from Psychotria spp. of the South Region of Brazil. <![CDATA[A literature review of the pollination strategies and breeding systems in Oncidiinae orchids]]> ABSTRACT Oncidiinae is an exclusively Neotropical orchid subtribe with about 1600 described species and an impressive array of vegetative and floral morphological adaptations. We present the results of a literature survey on the pollination strategies and breeding systems of this orchid subtribe. The flowers are pollinated by a wide range of insects (mostly bees) and, sometimes, hummingbirds. Several genera reward their pollinators with floral resources such as oils, nectar or perfumes. Whereas pollination by oil-gathering bees likely evolved several times within Oncidiinae, exclusive pollination by perfume-gathering male Euglossine bees is likely restricted to a set of closely-related genera. Pollination by food or sexual deception is also present within the subtribe. Up to date, the pollen-vectors of the 92 species of Oncidiinae studied so far are as follows: 84.7 % are pollinated by bees, 6.5 % by wasps, 4.3 % by hummingbirds, 3.2 % by butterflies and 3.2 % by flies. Oncidiinae orchids are preferentially self-incompatible (69.4 % of the species studied so far), some may also present protandry as a mechanism to promote cross-pollination. Fruiting success is generally low. The rate of visitation with subsequent pollination is low, in general, which contributes to the low reproductive success of this plant group. <![CDATA[Updates on extratropical region climbing plant flora: news regarding a still-neglected diversity]]> ABSTRACT Most studies concerning climbing plants have focused on lianas, forest ecosystems, and tropical regions. Thus, the majority of existing information is not relevant to all climbing plants (lianas and vines) or all ecoregions of the world (forested and non-forested). We provide an update on floristic and distributional data available for climbing plants in Rio Grande do Sul, Brazil’s southernmost state, which is located within subtropical and temperate zones and includes a variety of forest and non-forest vegetation types. A total of 448 climbing plant species were confirmed and documented by voucher specimens, revealing a diversity similar to that registered for trees in the state (533). The significant contribution of climbing species to the regional flora, the differences in floristic composition and species richness among the state’s eight vegetation types, and the high number of endangered species found in this extratropical region reveal the requirement to expand studies of climbing plants to include environments beyond tropical forests. Furthermore, the importance of herbaceous climbing species in subtropical and temperate floras demonstrates that they should be included in ecological studies of climbing plants, and that future analyses could detect unique or divergent patterns between herbaceous and woody climbers. <![CDATA[Invasion and establishment of <em>Ceratium furcoides</em> (Dinophyceae) in an urban lake in Porto Alegre, RS, Brazil]]> ABSTRACT Ceratium furcoides has received attention due its invasive behavior in South America and consequent alterations in local phytoplankton communities. Pedalinhos Lake had been dominated by chlorophytes until 2015, when the first occurrence of this dinoflagellate was detected. In order to investigate the colonization process of this species, we monitored the meteorological variables and phytoplankton abundance of this urban lake on a weekly basis from September 2015 to September 2018. At the beginning of the invasion process (Year 1), a peak density of 10,170 ind.mL-1 was recorded, with a significant decrease to 23 ind.mL-1, indicating an initial, unstable process of adaptation, with notable oscillation and reduction of cyanobacterial blooms. At this time, abundance of C. furcoides revealed inverse correlations with cyanobacteria, temperature, and insolation. InYear 2 therewere a stabilization of the density of C. furcoides accompanied by increased cell size. Year 3 (starting in September 2017) was again marked by oscillations in the density of this dinoflagellate. This study contributes to improved understanding of the adaptation process of this dinoflagellate in an invaded environment and its effects on the local phytoplankton community. <![CDATA[Genetic diversity in <em>Calibrachoa pygmaea</em> (Solanaceae): A hawkmoth-pollinated nightshade from the Pampas]]> ABSTRACT Calibrachoa pygmaea is a unique species of Calibrachoa, especially concerning its flower morphology and the environment where it occurs. The species is self-incompatible and is narrowly distributed in wet and flooded fields of the Pampas region. We characterize the genetic diversity of the species based on traditional plastid markers and newly developed nuclear microsatellites to identify drivers that guide its evolution. Our results identified markers that are informative and useful for studying the population structure of C. pygmaea, as well as that of other species of Calibrachoa. Both marker sets were congruent in developing conclusions regarding the evolutionary scenario of C. pygmaea, and revealed that the genetic variability and population structure of the species could be explained by common allele fixation or shared ancestral polymorphism, while its diversification can be attributed mainly to the species’ dispersal ability and certain ecological features. <![CDATA[Synflorescence morphology of species of <em>Typha</em> L. (Typhaceae): anatomical and ontogenetic bases for taxonomic applications]]> ABSTRACT The inflorescence of plants of the genus Typha L. consists of a polytelic system with the fertile region containing staminate flowers in the terminal portion and pistillate flowers in the basal portion. Although some useful morphological information has been provided to characterize species of the genus, various divergent typologies have arisen due to mistaken interpretations that ignore the different degrees of branching in this indeterminate system. The present study aimed to identify structural homologies by comparing the morphology and ontogeny of the synflorescences of Typha domingensis, T. latifolia and their putative hybrid, T. x provincialis, using standard micro-techniques for light and electron microscopy. Analysis revealed that the synflorescence of species of Typha should be considered a homothetic triple raceme. New diagnostic characters are proposed for both the pistillate and staminate portions. Differences among the apices of the pistillate portions are compared for the first time, and mainly involve the rate of lengthening of the second order branch, which is species specific. The data and interpretations proposed in this study should serve as a basis for proposing homologies for different structures of the synflorescences of species of Typha. <![CDATA[Catalogue of the vascular epiphytic flora of Uruguay]]> ABSTRACT We provide an updated list of the vascular epiphytic flora occurring in native environments of Uruguay based on literature review, herbarium specimens, and fieldwork throughout the country. The catalogue provides standardized information for each species, including accepted name, synonyms used within Uruguay, epiphytic category, distribution within the country, habitat, conservation status, observations, and a voucher citation. The effort documented 73 species for the epiphytic flora of Uruguay (3 % of the flora), distributed among 29 genera and 12 families. Bromeliaceae was the richest family (17), followed by Polypodiaceae (16) and Orchidaceae (12). Tillandsia stood out as the most speciose genus with 15 species. Characteristic holoepiphytes was the most diverse ecological category. More than half of the epiphytic species documented for Uruguay (53 %) reach their southernmost geographic distribution in the country, whereas only two mostly epipetric species of Tillandsia - T. arequitae and T. uruguayensis - are endemic to the country. Almost half of the epiphytic species found are presently under categories of threat of extinction, with 60 % of them occurring in national protected areas. Both the richest epiphytic families and the predominance of characteristic holoepiphytes coincide with findings from floristic and ecological studies previously carried out in humid subtropical regions. <![CDATA[Aquatic vascular plants of South Brazil: checklist and a comparative floristic approach]]> ABSTRACT Aquatic ecosystems support species diversity, and knowledge of plant communities is essential for wetland conservation programs. This study provides a checklist of aquatic vascular plants of South Brazil and establishes their floristic affinities with bordering South America phytogeographical domains. The checklist was based on 52 sources, including 35 floristic lists, 17 regional taxonomic studies, and information from an electronic database on wetlands of South Brazil. Floristic similarities with published checklists for neighbouring regions were assessed. A total of 780 species distributed in 277 genera and 85 families of vascular plants were reported for South Brazil. Families with higher species richness were Cyperaceae (128), Poaceae (102), Asteraceae (69), Plantaginaceae (21), Lentibulariaceae (20), and Onagraceae (20). The most represented genera were Eleocharis (41) and Cyperus (24). A cluster analysis revealed high similarity with Iberá (Argentinian Chaco), Pampa and Atlantic Forest, and low similarity with Pantanal, Caatinga and the Amazon Rainforest. The high number of aquatic plant families recorded relative to temperate and tropical climates suggests a zone of biogeographical overlap in Southern Brazil. The compiled data set reveals high biodiversity of wetlands of South Brazil, provides a baseline for future research, and highlights the need for regional conservation planning. <![CDATA[A new glandular <em>Mimosa</em> species from Southern Brazil and insights about its glandular trichomes micromorphology]]> ABSTRACT Mimosa baptistae is a new species presenting stalked glandular trichomes that give it a glutinous appearance, mainly with respect to the leaflets. Furthermore, it is an aculeate species, with multijugate leaves, white stamens, and fruits also covered by glandular trichomes. A herbaria survey and fieldwork only recorded this species as occurring on sandstone outcrops of the city Caçapava do Sul, Brazil. The species may be confused with other species of Mimosa sect. Batocaulon ser. Stipellares such as M. bifurca, M. sobralii and M. lepidota. However, features such as absence/presence of aculei, stamens color, habitat, and flower features are useful for distinguishing them from the new species. Here, we provide notes on morphology, geographic distribution, as well as anatomical detail of its glandular trichomes and content. Finally, we discussed the taxonomic significance of the micromorphology of glandular trichomes and their content in Mimosa ser. Stipellares as well as the potential applicability of such features to better understand the morphology of this series. <![CDATA[Species boundary and extensive hybridization and introgression in <em>Petunia</em>]]> ABSTRACT Studying the role of hybridization in the speciation of plants is one of the most thrilling areas of evolutionary biology. Hybridization in natural populations can act in opposition to divergence, contribute to adaptation through introgression or foster the emergence of new lineages via hybrid speciation. Species of the plant genus Petunia grow in open areas in southern South America. Some natural interspecific hybrid events have been described for the genus, such as between the endemic P. exserta and the widespread P. axillaris. Both species occur in sympatry in Serra do Sudeste (Brazil), where they occur in diverse habitats and exhibit floral divergence, which has been related to the attraction of different primary pollinators. The present study evaluates the maintenance of the species boundaries front of hybridization and introgression. Direct and indirect methods of estimating gene exchange employed genotyping 720 reproductive plants and 611 progenies of both species with eight microsatellite loci. Gene exchange was found to be frequent and bidirectional between the species, indicating that introgression changes their genetic constitution in areas of sympatry. Limits of the studied species are being maintained because of the high level of inbreeding and backcrosses that are habitat-dependent. <![CDATA[Morphological and genetic perspectives of hybridization in two contact zones of closely related species of <em>Petunia</em> (Solanaceae) in southern Brazil]]> ABSTRACT Interspecific hybridization has several consequences for parental species, from blurring species limits to the emergence of new taxa. Petunia axillaris and P. exserta occur in sympatry in southernmost Brazil and naturally hybridize despite their different pollination syndromes and habitat requirements. We employed genetic and morphological analyses to characterize two contact zones between the species with the aim of determining the effect of interspecific hybridization. Microsatellite loci and a morphometric evaluation of the corolla shape were used to classify individuals based on their origin as pure parental or hybrids. Corolla color was used to classify individuals a priori (white, red or intermediate, for P. axillaris, P. exserta or hybrid, respectively). Corolla color was found to be a good indicator of the genetic component of each species and their hybrid, while the shape of the corolla did not always correspond to genetic origin. Hybridization increased the variability, and introgression occurred in both directions in this system. <![CDATA[A taxonomic synopsis of <em>Cypella</em> (Iridaceae) in Brazil]]> ABSTRACT A taxonomic synopsis of Cypella (Iridaceae) in Brazil is presented with recognition of 16 species, two of them represented by two subspecies. An identification key to the taxa is provided and species are described and illustrated. New synonyms are indicated, and eight lectotypes, two epitypes and one neotype are designated. Results include distribution, habitat, phenology, conservation status, notes and examined specimens of all taxa, as well as comments on dubious and misused names. The resulting framework revealed that most of the Brazilian species of Cypella occur in the state of Rio Grande do Sul and in the Pampa Biome, although Río de la Plata grasslands (RPG) is the most species-rich biogeographic unit of the genus. <![CDATA[Future uncertainties for the distribution and conservation of <em>Paubrasilia echinata</em> under climate change]]> ABSTRACT Paubrasilia echinata is a widely cultivated endangered tree species with small populations restricted to a narrow strip of habitats along the Brazilian coast. The potential impacts of climate change on the distribution of P. echinata have yet to be investigated, and so it remains unknown whether protected areas will ensure the persistence of the species in the future. Here, we estimate the impacts of climate change on the distribution of P. echinata inside and outside of protected areas considering different climate change scenarios and two different sets of presence records: natural distribution and cultivated records. Future scenarios showed a gradual reduction in climatically suitable area both inside and outside of protected areas. Projections indicate a trend for a shift to the highlands of Southeast Brazil, and the loss of several areas throughout the entire distribution of the species. Predicted climatic conditions will be unsuitable for P. echinata inside most protected areas. Information provided here will be relevant in planning future national actions for this species, which is a must to properly protect this long-exploited tree. <![CDATA[Functional patterns of tree communities in natural <em>Araucaria</em> forests and old monoculture conifer plantations]]> ABSTRACT A functional perspective of tree communities is helpful for understanding forest dynamics, especially vegetation recovery after other land uses. Knowledge about ecological filters and survival strategies of trees are also important for the restoration of degraded areas. This study aimed to evaluate the functional composition and structure of adult and regenerative components of natural Araucaria forests, Araucaria plantations and plantations of exotic Pinus in subtropical southern Brazil. Differences in functional diversity and functional richness, and in community weighted mean trait values, including leaf traits and reproductive traits, were analyzed. RLQ analysis was used to assess the association between community structure, plant traits and environmental variables. Clear differences were found for most traits and for functional richness for the regenerative component, while the adult component was more similar among forest types. A clear separation in RLQ ordination associated with trait variation, for the adult component but not for regenerative trees, also indicates that communities are becoming functionally more similar with time. Plantations were shown to function as environmental filters by directly influencing species recruitment, richness and functional diversity. We conclude that passive restoration may be the best strategy for restoration of Araucaria forests. <![CDATA[Grassland vegetation sampling - a practical guide for sampling and data analysis]]> ABSTRACT Grassland and savanna ecosystems are the original vegetation types of more than 30% of the Brazilian territory, but conservation and training of future professionals has largely focused on forests. In fact, no standard protocols exist for sampling grassland vegetation for environmental planning or licensing. Neglecting non-forest ecosystems may have deleterious consequences for the maintenance of biodiversity and the provisioning of ecosystem services. Herein, we provide practical guidelines on how to conceive and develop ecological studies of grassland vegetation for scientific, monitoring or technical purposes. Using examples mostly from southern Brazil, we explain and discuss the various components of the research process, from the question to be investigated to defining and implementing the sampling design, performing data analyses and presenting the results. Our guidelines should prove useful for training technicians and researchers working on grassland ecosystems and other non-forest ecosystems in Brazil and surrounding regions.