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Ocotea catharinensis occurs mainly in the Brazilian Atlantic Forest and is highly threatened by timber logging, forest fragmentation, and habitat loss. The remnant populations of this species are genetically rich, which may be related to the presence of long-lived trees, and so it is imperative to understand their growth and age. In this study, we analyzed trees of O. catharinensis from dense ombrophylous forest, its dendrochronological potential, the period of cambial activity and dormancy, and the influence of climate on annual growth. The species showed distinct annually-formed tree-rings, with cambial activity during summer and autumn, and cambial dormancy during winter and spring. A tree-ring width chronology was built from 1852–2015. The estimated age of the sampled trees varied from 40 to 164 years. O. catharinensis in our study site does not show a strong age–diameter relationship, hence similar diameters at breast height resulted in differences in ages by as much as 50 years. The resulting tree-ring width chronology is positively correlated with March precipitation, the transition month between rainy and dry seasons. This study brings valuable contributions to the understanding of the growth of O. catharinensis, which is a novelty for this species and important to the maintenance of these long-lived trees in natural forests.

Endangered Brazilian tree species are traded on national and international scales. Efficient control of wood supply chains is fundamental to both species and environmental conservation. Wood anatomy offers an effective method for timber screening and diagnosis, although diagnostic tools and reliable reference materials are required to verify the precise timber species commercialized. We present here anatomical information that can be used for the identification of the wood of endangered Brazilian tree species, including coded wood anatomy descriptions following standardized lists of macroscopic and microscopic features, stereomicroscope and bright field microscope micrographs, and reference data (wood collections with reference samples and anatomical descriptions). Description datasets and interactive identification keys (macroscopic and microscopic) were made available on the Xper3 web platform (http://gbg.sites.uff.br/lamad/) and can aid trained front-line staff or professional wood anatomists in trade control and forensic timber identifications of endangered Brazilian species.

Paubrasilia echinata is recognized as the best wood in the manufacture of high-quality bows for string instruments. The wood anatomy of five historic French violin bows of the 19th and 20th century made of Pernambuco wood were investigated in order to reveal the wood anatomic features of these historical bows, to determine which P. echinata morphotype (arruda, café or laranja) was used in their manufacture and to identify the state of origin of the wood. Five bow samples were compared to 33 P. echinata specimens from the Brazilian states of Rio de Janeiro, Bahia, Paraíba and Rio Grande do Norte. The wood anatomical features were compared by means of principal component analysis, which revealed the type of axial parenchyma and percentage of tissue to be the most important to sort specimens. The best wood anatomical features previously described for high-quality bows were corroborated here and the bows in general showed similar wood anatomical features. Based on wood anatomy we found that the violin bows were most similar to the samples from the arruda morphotype derived from the States of Paraíba and Rio Grande do Norte by presenting scanty, unilateral and vasicentric axial parenchyma without confluences forming bands, higher percentage of fibres and lower percentage of axial parenchyma. We can therefore suggest that the historical French violin bows studied here were all made of the arruda morphotype from the Brazilian Northeast region helping explain the preference of the French explorers for this region.

The present ontogenetic study reveals variations throughout floral development in three morphologically representative species from the genusThis work aims to perform an ontogenetic study ofWe found the studied species to have floral buds with acropetal and helical development along the inflorescence axis; sepals and petals with helical development, varying the position of the primordia in the bud, according to the different species; stamens with unilateral development and carpel with adaxial curvature. These data correspond to original records of

The Program for Biodiversity Research (PPBio) is an innovative program designed to integrate all biodiversity research stakeholders. Operating since 2004, it has installed long-term ecological research sites throughout Brazil and its logic has been applied in some other southern-hemisphere countries. The program supports all aspects of research necessary to understand biodiversity and the processes that affect it. There are presently 161 sampling sites (see some of them at Supplementary Appendix), most of which use a standardized methodology that allows comparisons across biomes and through time. To date, there are about 1200 publications associated with PPBio that cover topics ranging from natural history to genetics and species distributions. Most of the field data and metadata are available through PPBio web sites or DataONE. Metadata is available for researchers that intend to explore the different faces of Brazilian biodiversity spatio-temporal variation, as well as for managers intending to improve conservation strategies. The Program also fostered, directly and indirectly, local technical capacity building, and supported the training of hundreds of undergraduate and graduate students. The main challenge is maintaining the long-term funding necessary to understand biodiversity patterns and processes under pressure from global environmental changes. Made available in DSpace on 2021-09-03T12:00:26Z (GMT). No. of bitstreams: 1 Program-for-Biodiversity-Research-2021.pdf: 4613827 bytes, checksum: 04b1875a6efdcba448fd73c1ecddf986 (MD5) Previous issue date: 2021

Salt stress is harmful to plants, especially for those that live under conditions of intense salt aport. For this reason, several species present alternatives to prevent or diminish the damages that high salt concentrations may cause to the cells. Salt glands are one of these alternatives once they are specialized structures that secrete salt. Here, we aimed to investigate if the glandular trichomes in the leaves of Jacquinia armillaris are salt glands. Anatomical and ultrastructural observations showed that the glandular trichomes in J. armillaris resemble the salt glands from other recretohalophytes Primulaceae, such as, their occurrence in sunken regions in the leaf epidermis, the presence of a large basal cell that acts as a collecting cell, the detachment of the cuticle from the outer periclinal walls forming a cuticular chamber, the thickness of the cuticle in the stalk portion of the trichome, and the presence of sodium and chloride ions in the secretion and in the xylem. Altogether, the gathered results support the hypothesis that the glandular trichomes in J. armillaris are adapted to salt secretion, thus characterizing as salt glands.

Baccharis L. is an important genus in the high-altitude environments of South America. In the State of Rio de Janeiro, southeastern Brazil, the greatest richness is found at montane and high-montane ecological refuges, known as high-altitude grasslands. The high altitude provides several environmental factors that turn the high-altitude grasslands into singular tropical habitats. In this article we describe the leaf anatomy of six shrubby species of Baccharis, pointing out ecological aspects of the structures, and testing the use of statistical analyses to compare the species. Using light and scanning electron microscopy, we compared the anatomical features of the leaves and performed a cluster and principal component analyses. The results show novel features in the leaf anatomy for the genus, such as an undulated cuticle, three secretory ducts in the midrib, secretory ducts associated with the xylem, and biseriate glandular trichomes with an irregular organization of the cells. Our statistical analyses indicate that the anatomical features of the leaves, especially trichomes, are useful for distinguishing the different species, whereas others, such as isobilateral mesophyll, amphistomatic leaves, and an epidermis with thick cell walls correlate with their high-elevation habitat.

Despite advances in understanding the ecology and consequences of pine invasions, information on the patterns of structure, dynamics, and growth needed to manage these invasive populations are still poorly known. Here we used tree ring analysis to elucidate growth dynamics, age distribution and fire effects, by sampling three populations of slash pine invading Cerrado vegetation in southeastern Brazil. We found that the invasion occurred in waves, every 5–7 years. These pulses are likely related to the time needed by founder trees to reach maturity, and to climatic events. We found distinct growth patterns among the three study areas. Individual trees in the open sites, under low competition for light, showed an increasing trend of diameter and of the basal area growth rates with age. In the dense stands, however, the diameter increment rates gradually decreased with age, as the competition for light was intensified, and the basal area growth rate increased at lower rates. Growth rates were markedly reduced after fire, likely due to fire impact on the canopies, reducing photosynthesis. Fire scars in the wood allowed us to confirm that the formation of the tree rings occurs annually. When competition for light intensifies as the canopy of the stand closes, the invasive populations experience reduced individual growth of adult trees and constraints to the recruitment of young individuals. We did not find, however, evidence of self-thinning due to competition that could reduce the population of adult trees, open gaps and allow colonization by shade-tolerant native species. Therefore, a monodominant pine stand—the “pine desert” feature of the invaded sites—tends to be persistent over time.

Clusia (Clusiaceae) species are known for their large ecological and pharmacological relevance, which are associated with the presence of secretory structures found in all plant organs, such as colleters and secretory ducts. Despite their importance, detailed aspects on the origin and development of such remarkable structures remains unknown and understanding their structure and activity ranges will contribute to taxonomic, phylogenetic and pharmacological studies. In this sense, we aimed to analyze secretory structures in Clusia fluminensis and Clusia lanceolata leaves to answer the following questions: (i) how does the ontogeny process occur? (ii) which classes of substances are produced by these secretory structures? (iii) how does the secretory process occur? For this it was used light, epifluorescence, confocal and electron microscopy. Colleters and secretory ducts were found in C. fluminensis and C. lanceolata leaves. The colleters have their origin in the protoderm and subepidermal layers of ground meristem and produce mucopolysaccharides and phenols when matured. Some indicatives imply that the entire structure is involved in the granulocrine secretory process. The latex ducts presented schizogenous origin in both species. In the leaf primordia these ducts incorporate meristematic cells by the end of already formed stem ducts. These meristematic cells undergo mitotic divisions and the middle lamella between them dissolute, causing the formation of the lumen. In expanded leaves such cells are distributed throughout the leaf lamina and present branches. Epithelial cells produce latex, which is secreted by a granulocrine process. Based on the nature of the secretions and the early development, colleters and latex ducts seems to be involved in the plant defense.

Understanding the behavior of trees and how they will respond to future climate change is a crucial conservation challenge, especially for tropical species. Despite the high diversity of tree species in Brazil, little is known about their tolerance limits. The study of tree rings is a valuable method for the analysis of growth dynamics with superposed epoch analysis being a good way to understand whether past dry years induce decreased tree growth, how long it takes to recover growth after a dry period, and the resilience of trees. This study investigated seven legume species (deciduous and evergreen) from three different sites in the Atlantic Forest in the state of Rio de Janeiro, Brazil. The studied trees seem to have coped well with the drought periods experienced thus far with no common pattern of recovery among species at the same site. The trees were not affected in a similar way and so different mechanisms are likely involved in preventing significant decreases in growth. These data are important for conservation policies because they reveal that each species requires a unique analysis., We thank the Laboratorio de Botanica Estrutural from Instituto de Pesquisas Jardim Botanico do Rio de Janeiro and the CNPq (Conselho Nacional de Desenvolvimento Científico Tecnologico) for the PDJ and Pesquisador Visitante fellowships, as well as CAPES (Coordenaçao de Aperfeiçoamento de Pessoal de Nível Superior), PPBIO (Programa de Pesquisa em Biodiversidade), and FAPERJ (Fundaçao Carlos Chagas Filho de Amparo `a Pesquisa do Estado do Rio de Janeiro) for the research fellowship grant.

Forest edge effects promote striking microclimatic shifts that result in greater light exposure, increased air temperature and evapotranspiration rates, and reduced soil moisture can alter stem hydraulic conductivity. These environmental conditions greatly increase the risk of emboli in xylem, which can disrupt or even cease water transport. We investigated tropical tree species in contrasting sites to understand the influence that edge effects have on wood functional anatomy. We compared wood anatomical traits between trees of forest edge and forest interior sites. The species exhibited two types of xylem arrangements based on the distribution of parenchyma cells: Pseudopiptadenia inaequalis and Copaifera lucens, with paratracheal axial parenchyma (PP), and Eugenia excelsa and Erythroxylum cuspidifolium, with predominant apotracheal axial parenchyma (AP). Tree species with PP xylem possessed shorter and wider vessel elements and lower ray and vessel frequencies, while species with AP xylem possessed longer and narrower vessel elements and higher ray and vessel frequencies. Regardless of the axial parenchyma arrangement, all four species had a greater percentage of axial parenchyma at the edge sites. The different xylem arrangements showed distinct responses to the edge effect in vessel frequency. The tropical tree species studied here shift to a greater abundance of axial parenchyma when subjected to effects of forest edge, probably to ensure safe water transport. This behavior, in the face of environmental stresses, is a plastic response, and likely due to functional versatility of parenchyma cells. The patterns of vessel frequency for PP and AP suggest that these xylem arrangements can be considered functional groups since the species in each group share similar traits and have similar strategies for conducting and maintaining water flow., This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); and Fundação de Amparo à Pesquisa do Rio de Janeiro (FAPERJ); Rede de Pesquisas PPBio Mata Atlântica – Brasil (PPBio-Ma).

Fruit morphology of the tribe Malveae has been discussed since the first taxonomic classifications of Malvaceae. The fruits are schizocarps, with some genera possessing an endoglossum. Besides morphological variation in the endoglossum, other differences include the number seeds per locule and ornamentation of the exocarp. An in-depth study of the fruit morphology of Malveae is essential to gain insight into the relationships among taxa of the tribe. Therefore, the present study aimed to describe the fruit morphology of Malveae, including micromorphology, variation in endoglossum structure and arrangement of seeds in the locule, to comprehensively evaluate the systematic relationships among its contained taxa. The results indicate morphological variation in fruit of various genera with regard to the number of mericarps, degree of dehiscence, relationship between calyx and fruit and their relative sizes, number and morphology of spines, number of seeds per locule, presence or absence of an endoglossum, presence and types of trichomes in exocarp and endocarp, and shape and presence of trichomes in the testa of seeds. Despite the morphological proximity of taxa, there are distinct combinations of characters that define some genera, and when one or more characters overlap, joint analysis makes it possible to clarify existing relationships.

Stryphnodendron Mart. is a widespread genus in the Neotropics and its species are widely used for their timber, in popular medicine, and for tanning. The similarities in their external morphology make species identification difficult in this genus. This study describes and compares the wood anatomy of the seven species of Stryphnodendron most frequently found in Brazilian forest remnants, in order to identify which anatomical features can be used in their segregation. From seven species 31 samples of Stryphnodendron were studied. Principal Component Analysis was used to evaluate wood anatomical characters. The species were separated into two main groups, congruent with the division into multifoliolate and paucifoliolate species, due to the presence of diffuse, lozenge-aliform and confluent axial parenchyma. In the multifoliolate group, although two subgroups were formed due to ray width in number of cells, none of the species were individualised, which corroborates previous findings of high morphological and anatomical similarities of the multifoliolate species.

This paper provides an overview of radial growth and tree-ring formation of two tropical tree species used in ecological restoration. It shows that trees growing in natural forests and in plantations have the same diametric growth patterns and climate responses. Understanding the outcomes of ecological restoration projects represents an important step in the conservation of endangered biomes such as the Atlantic forest in Brazil. Tree-ring analysis provides long-term information about the growth dynamics of tree species that can be used to evaluate the potential of different species for restoration projects. To evaluate the potential of using Pseudobombax grandiflorum (Cav.) A. Robyns and Citharexylum myrianthum Cham. in restoration projects in the endangered Atlantic Rain Forest (Reserva Biologica de Poco das Antas—RBPA, Rio de Janeiro, Brazil), we verified the seasonality of tree-ring formation to analyze radial growth dynamics and climate–growth relationships of these species. Cambium wounding experiments and direct anatomical analysis of the cambial zone were conducted to assess tree-ring formation periodicity. Tree-ring widths were measured to build tree-ring chronologies and to estimate radial growth rates in natural and planted areas. Both species produced annual tree rings that are produced during the wet season. Tree-ring chronologies of both species have a positive association with rainfall, but each species also responded to rainfall of a specific season. Tree-ring widths of P. grandiflorum were correlated with rainfall at the end of the previous growth season while tree-ring widths of C. myrianthum were correlated with precipitation in the beginning of the growth season. Both species have fast radial growth, but different long-term growth trends. The growth trend for Pseudobombax grandiflorum produces a positive correlation between diameter and age for the trees, while trees of Citharexylum myrianthum have an age-related growth trend and grow faster in the early years. In the present study, we confirm the success of the ecological restoration performed in RBPA as the plantation does not affect the potential growth of the studied species.

Many species of Primulaceae have chemical or medicinal importance, directly related to the presence of an important set of secretory structures distributed throughout the entire plant. Such structures are not only relevant in a pharmaceutical context, but also for taxonomic, systematic, and evolutionary studies within the family. Despite this, studies of the secretory structures in Primulaceae are still scarce. In this context, we aimed to identify and classify the diversity of secretory structures on the leaves of five Neotropical Primulaceae genera belonging to the Myrsinoideae and Theophrastoideae subfamilies, using light, confocal, and epifluorescence microscopy analysis. The species we studied had a diversity of secretory structures: mucilaginous and phenolic-content idioblasts, glandular trichomes, hydathodes, and secretory cavities/ducts. The development of secretory cavities and trichomes is asynchronous and begins before tissue and leaf maturation. Secretory cavities derive from a ground meristem cell and follow a schizogenous mode of development. The chemical nature of the secretion is diverse and varies according to the type of secretory structure and among species. Here, we hypothesize that both peltate glandular trichomes and secretory cavities may be considered a synapomorphy for Primulaceae. Moreover, we suggest that environmental factors have shaped the diversification of function of the secretory structures found in Primulaceae.

Paullinia comprises 220 species. In Brazil, there are 99 species of the genus distributed mainly in Amazonian forest and the Atlantic Forest, where there are 73 and 26 species, respectively. Until now, the stem anatomy of only 13 species of Paullinia has been investigated. Given the importance of information on cambial variants to the taxonomy of Sapindaceae, studies on the stem anatomy of species in the family are very relevant. The present study described the stem diversity of ten species of Paullinia, which were collected in areas difficult to access in Amazonian forest, in the state of Acre. Micro- and macroscopic analyses were carried out. Two types of cambial variants were identified: lobed stem and xylem interrupted by phloem wedges. The latter type was recorded for the first time in the genus. The anatomical study recorded different traits that might be useful for distinguishing taxa, including morphologically similar species, such as P. bracteosa and P. imberbes and P. fimbriata and P. rugosa. We believe that the results enrich the taxonomic descriptions of the analyzed species and will provide data for future evolutionary studies of the group.

Our main goals were to identify diagnostic characters at the species, genus, and subfamily levels, find anatomical features with potential for future morphological and molecular (combined) phylogenetic analyses, and to reconstruct the evolution of wood anatomical characters in two subfamilies of Primulaceae in a molecular phylogenetic framework. We investigated twenty-seven species from the woody Myrsinoideae (4 genera) and Theophrastoideae (2 genera) using scanning electron, light, and epifluorescence microscopy. Samples were prepared using standard protocols. Based on the wood anatomical characters, we were able to identify synapomorphies and to detect evolutionary trends of interest for the genera and subfamilies. Both subfamilies share the presence of diffuse porosity, simple perforation plates, septate fibres, and scanty paratracheal axial parenchyma. Theophrastoideae species have rays > 10 cells wide and short (

Studies have identified the central region of the Brazilian Atlantic Forest as an area of high biodiversity and endemism. Strong anthropogenic pressure has made protected areas in Rio de Janeiro State important sites for biodiversity conservation as they contain many areas of extreme biological importance. We sought to document and qualitatively describe the arboreal species composition of the Tinguá Biological Reserve by examining the collection data of the herbaria at the Instituto de Pesquisas Jardim Botânico do Rio de Janeiro (RB) and the Universidade Federal Rural do Rio de Janeiro (RBR). The survey identified 563 species belonging to 249 genera and 77 families, including 13 new occurrences for Rio de Janeiro State, 34 endemic species for the state, 17 vulnerable species, 15 endangered species, and one critically endangered species. Our results demonstrate the importance of this environmental protection area to the conservation of many plant populations and identified the region as harboring high tree diversity—thus reinforcing its role as an important forest remnant in a fragmented landscape within a threatened biome.

In the middle of a political and fiscal crisis, the Brazilian government is applying successive budget cuts, including in science funding. Recent cuts radically affect research programs on biodiversity that are crucial components for the design and monitoring of public policies for nature conservation and sustainable development. We analyze the consequences of such cuts on the Research Program on Biodiversity (PPBio), the largest biodiversity research network in Brazil (626 researchers, nine networks in all Brazilian biomes). Brazil holds a substantial part of the world's biodiversity and of tropical forests that play a significant role for regional and global climate stability. If underfunding is maintained, the dismantling of the Brazilian PPBio will have consequences that go beyond biodiversity knowledge itself but affect society as a whole. Brazil will likely fail to reach the National Targets for Biodiversity 2011–2020, and it will be difficult to fulfill the restoration target of the Brazilian NDC and to advance with the sustainable development goals. © 2017 Associação Brasileira de Ciência Ecológica e Conservação

Premise of research. This study tackles the general question of whether the assessment of leaf anatomical characters has potential utility in characterizing clades and taxa at various levels of the taxonomic hierarchy of the Primulaceae.Methodology. Fully expanded field-collected leaves of 33 species from five genera were sampled. The material was subjected to anatomical procedures by LM, SEM, confocal microscopy, and epifluorescence microscopy. Principal component analyses were performed to test the validity of leaf anatomical features as a method of separating the species and genera. In addition, to understand character evolution, some leaf anatomical characters were plotted on a DNA phylogeny.Pivotal results. The basic leaf anatomical structure was shared by all species: dorsiventral mesophyll, single-layered epidermis, and mesophyll cells containing druses. In contrast, other attributes, such as trichome types, stomata, and cuticular ornamentation, display diversity, which is helpful in defining group...

In this work we explore the radiocarbon (14C) signal as an independent tool to assess the year of formation of individual tree rings of tropical species in northern Brazil. Three different species were analyzed in this work: Dipteryx magnifica, Enterolobium maximum, and Hymenolobium petraeum. The studied samples are from the stem of only one individual of each species, all cut down in 2008 in Porto Trombetas, Pará, Brazil. Individual tree rings were identified based on wood anatomy and they were counted from bark to pith. Several rings were selected for 14C analysis in order to cover the overall shape of the 14C atmospheric bomb peak (after 1955). The 14C content was measured at Laboratory of Radiocarbon, Universidade Federal Fluminense (LAC-UFF). Results are compared with the Southern Hemisphere 14C atmospheric calibration curves. For E. maximum and H. petraeum the 14C signal exhibits an overall good match with the SH zone 3 and suggests annual seasonality in the growth-ring formation. These species offer suitable characteristics for dendrochronology. The D. magnifica shows mismatches in the 14C measurements that are likely a result of difficulties in identifying ring boundaries with certainty. Additional techniques may be helpful to disentangle the origin of this discrepancy.

Comparative studies of floral development and morphology have largely contributed to the understanding of taxonomic classification, phylogenetic relationships and evolutionary trends across many angiosperm clades, particularly in the florally diverse family Leguminosae (alternatively Fabaceae). This study aimed to characterize the middle to late stages of floral development and morphological variation of the caesalpinioid genus Tachigali, an evolutionary radiation of predominantly neotropical rainforest trees. Floral buds and flowers of five representative species from Tachigali were analyzed under stereo microscopy, light microscopy and scanning electron microscopy to evaluate informative morphological and developmental characters. Although the genus displays relatively small flowers measuring up to 14 mm long, they are variable in terms of symmetry, structure and size, which have influenced the main taxonomic subdivisions among the species. Here, we show that the floral architecture of Tachigali involves a double whorl of stamens, anthers with dome-shaped connective extension and monosymmetrical hypanthium, owing to the unequal development of its wall at different stages of the floral ontogeny. Such developmental patterns are likely new diagnostic floral characters of Tachigali in the context of the early diverging caesalpinioid clades and reaffirm the circumscription of the genus in order to include the species previously classified within Sclerolobium.

Tree-ring chronologies were built for wild and cultivated Paubrasilia echinata, a presently endangered species. Significantly P. echinata showed measurably different growth patterns related to the environment where wild and cultivated trees have grown. Paubrasilia echinata once grew so abundantly along the tropical coast of South America that the names given to the tree by early Europeans colonists—Bresil, Brasil, Brazil—became synonymous with an entire geography. Today, despite restoration and protection efforts, the species remains under threat of extinction throughout Brazil’s Atlantic Forest. Considering the past overexploitation and ongoing climate changes, the future of P. echinata significantly depends upon human understanding of the species’ growth dynamics and growth-climate relations. Therefore, this work aims to: (1) demonstrate the feasibility of calendar dating P. echinata tree rings; (2) build chronologies by analyzing its growth rings; and (3) establish with detail the specific influence of climate on annual radial xylem production. Differences in vessel and axial parenchyma frequency, local distended rays and marginal parenchyma were the wood anatomical markers used to distinguish boundaries between adjacent rings so that dendrochronological methods could be applied. For climate-growth responses, we developed tree-ring width chronologies from wild and cultivated trees. Results revealed that seasonal rainfall is the most important factor influencing P. echinata growth. More specifically, positive correlation was observed between the tree-ring chronology of wild trees and precipitation during the rainy months of the growing season, while the tree-ring chronology of cultivated trees correlated negatively with precipitation in months before the growth period. Wild trees showed increment growth rates lower than planted trees. Rainfall’s observed effect on P. echinata is, of course, not surprising. However, our results contribute a detailed quantitative record of that effect, which expands the body of ecological knowledge regarding P. echinata necessary for ongoing conservation efforts under current and future human-caused climate change.

Attempts to improve the ascorbate (AsA) content of plants are still dealing with the limited understanding of why exists a wide variability of this powerful anti-oxidant molecule in different plant sources, species and environmental situations. In plant mitochondria, the last step of AsA synthesis is catalyzed by the enzyme L-galactone-1,4-lactone dehydrogenase (L-GalLDH). By using GalLDH-RNAi silencing plant lines, biochemical and proteomic approaches, we here discovered that, in addition to accumulate this antioxidant, mitochondria synthesize AsA to down-regulate the respiratory activity and the cellular energy provision. The work reveals that the AsA synthesis pathway within mitochondria is a branched electron transfer process that channels electrons towards the alternative oxidase, interfering with conventional electron transport. It was unexpectedly found that significant hydrogen peroxide is generated during AsA synthesis, which affects the AsA level. The induced AsA synthesis shows proteomic alterations of mitochondrial and extra-mitochondrial proteins related to oxidative and energetic metabolism. The most identified proteins were known components of plant responses to high light acclimation, programmed cell death, oxidative stress, senescence, cell expansion, iron and phosphorus starvation, different abiotic stress/pathogen attack responses and others. We propose that changing the electron flux associated with AsA synthesis might be part of a new mechanism by which the L-GalLDH enzyme would adapt plant mitochondria to fluctuating energy demands and redox status occurring under different physiological contexts., Instituto de Fisiología Vegetal

Temporal instability and spatial inconsistency in tree growth sensitivity to climate have been reported, but little attention has been given to tropical species. Araucaria angustifolia (Bertol.) Kuntze. (Araucariaceae) is a critically endangered South American subtropical and tropical conifer. It offers the potential to evaluate alterations in tree growth responses as it is climate-sensitive and presents a core zone of distribution in the Brazilian meridional highlands (with small disjunct patches occurring in its most southern and northern ranges). Previous dendrochronological studies in the central and most southern distribution range of A. angustifolia showed different climate-related growth responses, which raises the question of whether the growth responses of A. angustifolia to climate are consistent over space and stable over time at the species' northern distribution limit? We developed well-replicated tree-ring chronologies for A. angustifolia at the species' northern distribution limit, examined its growth dynamics, and evaluated climate-growth relationships. The growth patterns of A. angustifolia allowed the synchronization of its tree ring time-series and the construction of two tree-ring width chronologies (at Brejo da Lapa – BL and Vale das Araucarias – VA) of 55 years and 171 years respectively. The chronologies demonstrated stable and robust signal strengths. Climate-growth response analyses indicated significant positive correlations of the VA chronology with precipitation variables, and with temperature variables in the BL chronology. Different diametric growth patterns were detected between BL and VA. We observed consistent reductions of growth responses to the climate in recent decades. Forest structure and dynamics, disturbance regime, local environmental factors, and climate change could generate physiological alterations and explain variations in A. angustifolia’s growth responses and increments. The species showed different sensitivities to climatic factors both spatially and temporally, and different growth patterns at its northern distribution limit.

The objective of this study was to survey species of Ombrophilous Dense Forest (Atlantic Forest) in the Serra da Jiboia (Bahia), Brazil, which have growth rings, to characterize their growth zones anatomically, and on the basis of these data and others already published, to provide an answer to some questions which are relevant to understanding why growth rings occur in species of the Atlantic Forest. The wood anatomy of 111 species collected in Ombrophilous Dense Forest in Bahia and Rio de Janeiro, belonging to 77 genera and 37 families, was studied to discover the presence of growth rings and if so to characterize them. Growth rings were present in most species (79 %), and of these, the majority showed anatomical markers characterized by thick-walled and/or radially flattened late wood fibres, although other markers may occur together with this one. The explanation for the occurrence of this marker in the growth rings of Atlantic Forest species may lie in historical-evolutionary factors. The absence of growth rings is positively related to the species collected in the Atlantic Forest compared to those of the Cerrado. However, the presence of poorly defined growth rings was shown to be negatively related to endemic species of the Ombrophilous Dense Forest, compared to those which occur in other vegetation types within the Atlantic Forest. Contrasting conditions of water availability and seasonality in these different habitats offer a theoretical basis to explain these patterns.

Knowledge about growth rhythm and longevity of tropical trees is essential to understand life strategies of native species, and consequently, of forest remnants. This study aims to investigate the growth dynamics of Centrolobium robustum, a representative species from Atlantic Forest. For this purpose, radial growth was examined through tree rings and cambium analysis, from macroscopical, anatomical, and ultrastructural perspectives. The apical and radial stem growth was evaluated through leaf and cambium phenology, respectively. Leaf and cambium behaviors were associated with environmental seasonality. The results showed that the period of cell production and cambial development occurred in association with leaf expansion and during the wet, warm, and long-day season. Seasonality of cambial and leaf phenology in response to the environment determined the annual formation of tree rings, and it allowed to evaluate C. robustum growth rates and longevity. Species seasonality also responded to abnormal climatic events during the study period, which shows its sensitivity to environmental changes and represents a factor to be considered in the forest management programs.

Colleters are secretory structure present on many families including Rubiaceae. Particular characteristics have been described about colleters secretory cells, however senescence process are still under debate. Tocoyena bullata (Vell.) Mart. (Rubiaceae) shoot apex were collected at Jardim Botânico do Rio de Janeiro, RJ/Brazil. Stipules were separated and fragments were fixed in 2.5% glutaraldehyde and 4.0% formaldehyde in 0.05 m sodium cacodylate buffer, pH 7.2, post fixed in 1.0% osmium tetroxide in the same buffer, dehydrated in acetone, critical-point-drying, sputtered coated and observed. For light microscopy fragments were fixed and dehydrated, infiltrated with historesin and stained with 1% toluidine blue. For transmission electron microscopy, the samples were infiltrated with Epoxi resin. Colleters are present on stipule adaxial surface. On the beginning of development, these structures are recognized as small projections. Later on, colleters differentiated and secrete by cuticle rupture. The colleters senescence occurs in a concomitant and indissoluble way of programmed cell death. Ultrastructural analyses during the process strongly suggest the senescence is based on a non-autolitic programmed cell death. T. bullata colleters, present at stipule abaxial surface are cylindrical secretory structures. Colleters secretory cells originated as stipule projections; differentiate; secrete and senesce by programmed cell death. The secretion and the cell dead occurs in a concomitantly and indissoluble way.

Tree growth sensitivity to climate can vary over space and time. This variability generates inconsistency in growth response to climate, which makes it difficult to assess the effects of past climate and global climate change on tree growth. A previous short-term study of Pseudopiptadenia contorta found a consistent growth response to climate in distinct locations, which raises the question, is the growth response of P. contorta to climate consistent over the long-term? We aimed to assess whether there is a common pattern of variation in tree-ring width, build tree-ring width chronologies, and verify the consistency of the climate-growth response of P. contorta in two Atlantic Forest remnants. Wood samples were collected in Reserva Biologica de Poco das Antas (RBPA) and Reserva Biologica de Tingua (RBT) in the state of Rio de Janeiro, Brazil. Conventional dendrochronology methods were used for cross-dating, to build chronologies and to assess the climate-growth relationship. A common growth pattern was detected for P. contorta, and two tree-ring width chronologies were constructed. A congruent growth response was found for trees of RBPA and RBT to annual and spring precipitation as well as precipitation in the rainy months. Other climate-growth relationships were detected with other precipitation and temperature variables. Considering that P. contorta is a widespread species, occurring in other Brazilian biomes and forest formations, it is a promising model for developing further dendrochronological research including regional networks of replicated site chronologies, which could facilitate the reconstruction of historical climatic series and predictions of future impacts of climate change in tropical areas.

Federally listed endangered plant species have restrictions regulating their extraction and transit in Brazil. However, dozens of endangered species are important for the national timber trade. The present research addresses the question: What endangered tree species were legally traded as timber in Brazil between 2012–2016 and how significant is this trade with respect to the total volume of timber? To answer this question, we surveyed wood taxa and wood volume transported during this period as recorded by the National System for the Environment (SISNAMA). Under Brazil’s federal environmental law (L12651 Art. 35) Brazilian Institute of Environment and Renewable Natural Resources (IBAMA) is responsible for the registration of all commercial forest products. The law stipulates that products receive a Document of Forest Origin (DOF) indicating species, quantity, commercial use, origin, and destination. We correlated this data with the federal list of endangered plant species in Brazil to aggregate the number of endangered species transported from 2012 to 2016 and the total volume associated with each species. Among the 2214 species traded, we found 38 endangered species, comprising a volume of 6 million m3, representing approximately ten percent of the total traffic of 60.9 million m3. The endangered species Araucaria angustifolia (Bertol.) Kuntze and Mezilaurus itauba (Meisn.) Taub. Ex Mez were among the twenty species with greatest volume transported and traded, respectively 3.2 million m3 and 789,522 m3. The presence of these endangered species at the top of the list of woods transported within the national territory raises serious questions for conservation policy and practices in Brazil. Monitoring changes in deforestation rates inadequately assesses the impacts of timber harvesting on endangered native tree species. The information provided by this study should be of interest to national and international environmental agencies, international trade control agencies, conservation biologists, researchers and policymakers working to produce more effective control of harvest and trade of endangered species.

Fire disturbance affects the composition, structure and dynamics of vegetation. Historical records of fire events exist in some places, but they are generally limited in temporal and spatial extent. Tree-ring research is a useful tool for fire history reconstruction and can contribute important long-term ecological data. We tested the hypotheses that Moquiniastrum polymorphum (Less.) G. Sancho, a widespread species in Brazil that occurs in burnt areas of Atlantic Forest, produces annual growth rings and that its wood can record fire incidence by datable fire scaring. Our results corroborate these hypotheses and indicate that the species has potential for fire history reconstruction.

Allagoptera arenaria (Arecaceae), commonly known as “guriri,” is a palm that occurs only along the sandy coastal environments of Brazil. This work carries out a thorough analysis of A. arenaria leaf anatomy, including histochemistry and micromorphology, with special emphasis on leaf epicuticular waxes. Several common features of palms were identified, as well as characters not yet reported for the family or the species. Allagoptera arenaria pinnae possess a one-layered epidermis, hypodermis with two adaxial layers and one abaxial layer, homogeneous mesophyll composed of palisade cells, three different types of collateral veins, a prominent adaxial midrib, and silica inclusions. Although both margins of A. arenaria pinnae have a similar appearance, the shape of the leaf margins can vary. Scales or ramenta were found on the abaxial surface of the midrib on the median and basal portions of the pinnae. Histochemical analysis revealed the presence of polyphenols, flavonoids, lignin, and neutral and acidic lipids. The most distinctive character of A. arenaria pinnae is the presence of a thick layer of epicuticular waxes covering both the adaxial and abaxial surfaces. These results suggest the potential for exploiting A. arenaria as an alternative source of industrial waxes.