Resumo em Inglês:

ABSTRACT This work validates two Waltheria species endemic to campo rupestre with complete descriptions, illustrations, updated geographical distributions and comments on taxonomic affinities. Waltheria biribiriensis and Waltheria terminans are restricted to the Southern Espinhaço Province in eastern South America, occurring on mountain tops where campo rupestre vegetation prevails. Furthermore, Waltheria brachypetala, a species of dry deciduous forests in Brazil that was long considered as conspecific with W. ferruginea due to its shrubby lifeform and similar indumentum, is re-established based on differences of phyllotaxy, blade shape and inflorescence type. The first occurrence records of W. brachypetala in the state of Paraíba are also provided, as well as the first record in the Atlantic Forest domain. Lastly, a lectotype is designated for W. ferruginea.

Resumo em Inglês:

ABSTRACT This study presents a systematic review to assess the main similarities and gaps in efforts to evaluate the impacts of heavy metals on benthic marine seaweeds. A total of 91 studies were compiled, the main parameters (abiotic, biological, ecotoxicological, and heavy metals) and descriptors of which were evaluated by quantitative and qualitative analyses. Our results indicate the importance of diversifying searches by including different languages (i.e. English, Portuguese and Spanish). Most of the studies were field characterizations, with few abiotic parameters and/or seasonality evaluations being employed. In contrast, the assessment of ecotoxicological parameters was highly frequent, which seems incoherent considering the absence of data to support the use of these results in biomonitoring applications. The genera Sargassum, Ulva and Enteromorpha were widely studied worldwide, apart from a small fraction of studies assessing higher levels of biological organization. Moreover, the use of different parameters and descriptors by the evaluated studies precludes making conclusive or reliable comparisons. These findings highlight the importance of greater efforts to construct a concise baseline of knowledge using similar parameters so that global evaluations of the impacts of heavy metals on photosynthetic organisms can be undertaken.

Resumo em Inglês:

ABSTRACT This study investigated the suitability of honey sample collection methods for determining the botanical origin of honey through palynological analysis. We used three methods to collect honey samples in three different modes viz. extracted honey using a honey extractor, squeezed honey and pipetted honey (collected by micropipette/dropper from honey cells only) during 2017 to 2019 in West Bengal, India. We considered two native honey bee species (Apis dorsata and Apis florea) and one introduced bee species (Apis mellifera). Pollen composition differed significantly, both quantitatively and qualitatively, among the honey samples of the different methods. The number of pollen grains in extracted honey and squeezed honey was significantly higher than that of pipetted honey. Furthermore, some pollen types of nectar deficient, but polleniferous plants (viz. Capparis zeylanica, Echinochloa frumentacea, Papaver somniferum, Poaceae type, Nelumbo nucifera, Solanum melongena, and Solanum sisymbriifolium), were also present in extracted and squeezed honeys. We concluded that some pollen grains present in extracted and squeezed honey samples came from stored pollen loads or bee bread in the hive. Hence, the pollen spectrum for pipetted honey samples was more accurate in depicting the bees foraging on nectariferous plants.

Resumo em Inglês:

ABSTRACT Soil nutrients are one of the main drivers of plant species composition and distribution, mainly due to the role they play in plant survival and reproductive success. However, the nutritional requirements of plants inhabiting their native ecosystems are still poorly known. This is the case for most species of campo rupestre vegetation, which are found on infertile soils of quartzitic and ferruginous origin. The present study evaluated the effects of macronutrients and substrates on survival and growth of the micro-endemic Vellozia nanuzae (Velloziaceae). Plant mortality was about 95 % higher in soil enriched with macronutrients and almost 100 % in soils with added manure in the first 30 days. Individual plants from treatments with added nutrients had lower growth (53 % less) compared to individuals on natural substrates. In conclusion, Vellozia nanuzaesurvived and developed better on soil of its original habitat even though it is acidic and poor in nutrients. Our results show that more nutrients are not always better for the survival and development of native species that inhabit harsh ecosystems.

Resumo em Inglês:

ABSTRACT Ferruginous Rocky Outcrops have high levels of species richness and endemism, but have been threatened by several anthropic actions, especially mining. Eragrostis polytricha, a common grass species in the vegetation of these outcrops, has shown promising features for use in the recovery of mining areas. However, in order to fully understand the species’ potential for such use, its requirements for germination, seed dormancy break and seedling development must be determined. Thus, we aimed to: (1) assess the temperature conditions needed for seeds of E. polytricha to germinate; (2) evaluate the effects of KNO₃ in breaking seed dormancy; and (3) analyze the germination efficiency of seeds that are still in spikelets. The experiment included seven treatments: 15-35 ºC with KNO₃, 20-30 ºC with KNO₃, 15 ºC with KNO₃, 25 ºC with KNO₃, 35 ºC with KNO₃, 20-30 ºC with water, and 20-30 ºC with KNO₃ using spikelets. The treatments with alternating temperatures associated with KNO3 yielded the highest germination rates, suggesting that these two factors combined can break seed dormancy. Seeds inside spikelets exhibited a high germination percentage, and thus represent an interesting alternative for seedling production.

Resumo em Inglês:

ABSTRACT Areas of cerrado (Brazilian savanna) in the Amazon have been poorly studied from the perspective of fire impacts on environmental sustainability, especially with regard to disturbances to soil and vegetation structure. This study aimed to analyze the influence of edaphic variables and fire together on the composition and structure of tree and shrub vegetation of three cerrado remnants in the Amazon. Eight plots were systematically installed in burned and unburned environments in each remnant. Data were submitted to floristic diversity, similarity, and diametric and altimetric structural assessments. Phytosociological parameters were obtained and submitted to Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA). A total of 808 individuals (34 species, 30 genera, and 21 families) were recorded. The CCA indicated that the distribution of species is influenced by edaphic factors, as confirmed by the strong direct correlation of tree and shrub species with the reduced nutrition and high acidity of the soils common in the analyzed remnants. Our results support the hypothesis that fire plays a relevant role in structuring vegetation since it contributed to good indicators of soil properties and caused changes in the composition of woody species.

Resumo em Inglês:

ABSTRACT A molecular phylogeny of the subfamily Ambavioideae (Annonaceae) was reconstructed using up to eight plastid DNA regions (matK, ndhF, and rbcL exons; trnL intron; atpB-rbcL, psbA-trnH, trnL-trnF, and trnS-trnG intergenic spacers). The results indicate that the subfamily is not monophyletic, with the monotypic genus Meiocarpidium resolved as the second diverging lineage of Annonaceae after Anaxagorea (the only genus of Anaxagoreoideae) and as the sister group of a large clade consisting of the rest of Annonaceae. Consequently, a new subfamily, Meiocarpidioideae, is established to accommodate the enigmatic African genus Meiocarpidium. In addition, the subfamily Ambavioideae is redefined to contain two major clades formally recognized as two tribes. The tribe Tetramerantheae consisting of only Tetrameranthus is enlarged to include Ambavia, Cleistopholis, and Mezzettia; and Canangeae, a new tribe comprising Cananga, Cyathocalyx, Drepananthus, and Lettowianthus, are erected. The two tribes are principally distinguishable from each other by differences in monoploid chromosome number, branching architecture, and average pollen size (monads). New relationships were retrieved within Tetramerantheae, with Mezzettia as the sister group of a clade containing Ambavia and Cleistopholis.

Resumo em Inglês:

ABSTRACT The Neotropical genera Aspidogyne and Microchilus (Goodyerinae, Cranichideae, Orchidaceae) comprise ca. 200 rainforests terrestrial species. Although species of Goodyerinae are described with similar anatomy to other taxa of Cranichideae, some anatomical characteristics appear to be specific to the subtribe. Our goal was to characterise the anatomical structure of the vegetative organs of Aspidogyne and Microchilus to identify specific characters of Goodyerinae. Root, stem and leaf samples from eleven species were analysed using light and scanning electron microscopy. The leaves are hypostomatic and glabrous with predominantly anisocytic or tetracytic stomata, thin cuticle, homogeneous mesophyll with chromoplast and raphides, and collateral vascular bundles with parenchyma sheath and collenchyma in the midrib. Spiranthosomes were cofirmed for all species and some specific characteristics were identified in the root, such as the presence of collenchyma in both the cortex and the stele, vascular tissue with fibre-tracheids in the centre of the vascular cylinder, and the presence of a true endodermis with Casparian strips in the stem. Therefore, the root and stem were the organs that showed more taxon-specific characteristics for Goodyerinae, which can be used to better delimited the subtribe.

Resumo em Inglês:

ABSTRACT Although knowledge about halophytic Solanaceae is scarce, it is known that several species within genus Lycium tolerate salinity. Lycium humile grows in highly saline soils in mudflats near saline Andean lakes. This study evaluated the germination responses of L. humile under different scarification methods, photoperiods, temperatures and saline conditions and, simultaneously, tested seedling survival under different iso-osmotic conditions. Dormancy and germination were found to be regulated by interactions with different factors, with the highest germination percentages being obtained by immersion in sulfuric acid, with a temperature of 25 °C and a temperature regime of 5/25 °C, under which seeds were neutrally photoblastic. As osmotic potential of saline solutions decreased, germination also decreased drastically but the seedling survival percentage was higher than 30 % at 600 mM NaCl. No seeds germinated in any of the polyethylene glycol (PEG) solutions and no seedling survival was observed from -1.2 MPa PEG solutions. More than 90 % of seeds incubated in NaCl were able to recover germination after being transferred to distilled water, independently of NaCl treatments. We concluded that the effects of extreme environmental conditions on germination responses and seed tolerance to salinity may determine the occurrence and restricted distribution of L. humile.

Resumo em Inglês:

ABSTRACT During a survey of Mucorales in soil from an upland forest area in Pernambuco, Brazil, two specimens were isolated and characterized based on their morphological, physiological, and molecular data (ITS and LSU rDNA). Phylogenetic analyses of the isolates revealed that the strains URM 8209 and URM 8210 are closely related to species of Absidia. URM 8209 forms conical, subglobose, and strawberry-shaped columellae and the sporangiospores are cylindrical and ellipsoid. URM 8210 produces hemispheric, subglobose, and strawberry-shaped columellae and the sporangiospores are globose, subglobose, ellipsoid, and short cylindrical. Based on evidence obtained through analysis of datasets (LSU and ITS rDNA regions), A. saloaensis sp. nov. (URM 8209) and A. multispora sp. nov. (URM 8210) are proposed here as novel species of Absidia. A table with morphological characteristics of Neotropical Absidia spp. is provided.

Resumo em Inglês:

ABSTRACT The distributions of species of Fabaceae are strongly related to the soil. Their presence can alter restrictive conditions and favour the establishment of other species. However, it is still not known how the relationship between species of Fabaceae and edaphic factors interact in structuring woody Chaco vegetation. In this context, we aimed to test the hypothesis that restrictive edaphic conditions can explain the difference in floristic patterns of two types of vegetation through their species representativeness of Fabaceae. We analysed floristic consistency between wooded and forested Chaco to address how spatial and environment components might explain differences between them along with the effects of the interaction between Fabaceae and the soil. We observed that the association between environmental and spatial variables was more important than any individual factor in explaining the structuring of the communities. Both the percentage of species of Fabaceae present and the soil influence the structure of the two types of vegetation. Species of Fabaceae have greater potential as indicators in the wooded Chaco. Therefore, we suggest the interaction between soil types and species of Fabaceae plays a role during the structuring of the communities through the establishment of these species in more restrictive soils.

Resumo em Inglês:

ABSTRACT We studied the leaf anatomy of 15 species of Byrsonima and a single species of Diacidia as an outgroup to test the relevance of leaf anatomical characters to the complicated taxonomy of this genus. We present complete anatomical descriptions for petioles and leaf blades, together with an anatomical matrix, dendrogram and an identification key for the studied taxa. The most informative characters were the presence of stomatal crest, trichome type, epidermis type, contour and conformation of the vascular system in the diaphragm and medium petiole and number of accessory bundles. The aforementioned characters revealed that the anatomy of the petioles in the genus differs from that of petioles in the outgroup taxon with regard to vascular system conformation and the absence of cortical sclereids. Furthermore, the anatomy of the leaf blade appears to be quite informative in Byrsonima, especially in synonymized species. The anatomical features evaluated here have great value for Byrsonima taxonomy. These features may be used in an evolutionary approach to the group, especially for proposing a new classification system based on morphoanatomical characters of the genus.

Resumo em Inglês:

ABSTRACT We report on the reproductive biology, pollinators, and thermogenesis of the widely distributed Araceae species, Xanthosoma striatipes. We analyzed the floral scent in one population and compared it to a previous study. Xanthosoma striatipes was studied at three sites in Brazil, São Paulo, Minas Gerais and Maranhão. The results showed constancy of the reproductive biology and main pollinator species across sites. The pollinators at all three sites sites were two species of cyclocephaline scarabs, Cyclocephala atricapilla and C. ohausiana. The scent composition of the strongly scented inflorescences of plants of a site in São Paulo differed from plants recently studied in Central Brazil. Of the 39 and 23 compounds detected, in the present and the previous study, respectively, only seven compounds, were in common. We discuss that the two main constituents identified in samples at both sites, the aromatic compound methyl salicylate and the terpenoid (E)-4,8-dimethyl-1,3,7-nonatriene, alone seem to be sufficient for the attraction of the beetles. However, it is also possible that different compounds are involved in attracting the same beetle species to plants of the different populations.

Resumo em Inglês:

ABSTRACT In 2019, the atmospheric CO2 concentration exceeded the 415 ppm milestone for the first time in the human history. According to projections of the Intergovernmental Panel on Climate Change (IPCC), CO2 levels will continue to rise in the future, potentially affecting all living organisms. Plants with C3 metabolism may benefit from rising CO2 levels because the significant losses of photosynthesis, driven by photorespiration could be diminished under this scenario. This study addressed the anatomical changes in the stems of young Eucalyptus urophylla plants induced through cultivation in elevated CO2 (eCO2). Plants cultivated under eCO2 showed increased stem diameter (i.e., radial width of the secondary xylem, secondary phloem and cortex tissues). Periodic acid-Schiff (PAS)/Toluidine Blue staining suggested a decrease in the lignification content in the newly formed tissues of eCO2 stimulated plants. Levels of caffeate/5-hydroxyferulate O-methyltransferase form 1 (COMT1), a lignin biosynthesis specific proteoform, were significantly reduced in stem sections, supporting our findings: eCO2 induces plant growth, but reduces lignified tissues.

Resumo em Inglês:

ABSTRACT Seeds of Erythrina speciosa (Papilionoideae) exhibit physical dormancy, but evidence has suggested that the proportion of impermeable seeds increases with storage. There are no records of structural variation in the testa of E. speciosa that justifies the difference in the percentage of seeds with physical dormancy. Therefore, the present study investigated the difference in permeability between mature seeds of E. speciosa that were freshly collected and those stored for 12 months. Seeds were examined for changes in testa structure that could result in differences in the percentage of seeds in physical dormancy. Thus, imbibition curves and water gaps were determined, and surface micromorphology, anatomy, and histochemistry of the testa were described. Our results revealed that the proportion of seeds with physical dormancy was higher in stored than in freshly collected seeds, with no anatomical changes in the testa to cause this difference. The analysis of surface micromorphology revealed that, in the lateral region of the seed (the water gap), the mucilaginous stratum was discontinuous in the freshly collected seeds and continuous in stored seeds. These results revealed that the mucilaginous stratum plays an important role in the acquisition and establishment of physical dormancy in E. speciosa.