Growth and functional leaf traits of coppice regrowth of Bertholletia excelsa during an El Niño event in the central Amazon / Crescimento e características funcionais foliares de rebrotas de Bertholletia excelsa durante um evento de El Niño na Amazônia Central

The most severe drought of this century in the Amazon rainforest, which was caused by El Niño, occurred from 2015 to 2016. With a focus on the ecophysiology of the regrowth of the Brazil nut tree, Bertholletia excelsa, it was investigated how the progression of the drought of 2015-2016 affected the physiological traits of the coppice regrowth of B. excelsa. The experiment was carried out in a ten-year-old plantation of Brazil nut trees, which had been subjected to thinning and coppice regrowth two years earlier. In the sprouts grown on the stumps of cut trees, the following treatments were applied: (T1) thinning to one sprout per stump; (T2) thinning to two sprouts per stump, and (T3) maintenance of three sprouts per stump. Thinning treatments did not alter the growth and ecophysiological traits of the Brazil nut tree sprouts, though the phosphorus content of the leaves was higher in T1. However, the progression of the drought in 2015-2016 negatively affected the growth (height) and gas exchange of sprouts of all treatments. In addition, an increase of around 37% was observed in the intrinsic wateruse efficiency. Concerning photochemical performance, no alterations were observed. Therefore, drought stress promoted a negative effect on sprout growth and affected traits related to the photosynthesis of the B. excelsa sprouts independently of the number of sprouts per stump.(AU)

A seca mais severa deste século na floresta amazônica, causada por El Niño, ocorreu de 2015 a 2016. Com foco na ecofisiologia da rebrota da castanheira da Amazônia, foi investigado como a progressão da seca de 2015-2016 afetou as características fisiológicas das rebrotas de uma talhadia de B. excelsa. O experimento foi realizado em uma plantação de castanheiras com dez anos, a qual havia sido submetida a um desbaste e rebrota de talhadia dois anos antes. Nas rebrotas crescidas sobre os tocos das árvores cortadas foram aplicados os seguintes tratamentos: (T1) desbrota para manter um broto por cepa; (T2) desbrota para manter dois brotos por cepa; e (T3) manutenção de três brotos por cepa. Os tratamentos de desbrota não alteraram o crescimento e as características ecofisiológicas dos brotos da castanheira, exceto para o teor foliar de fósforo, que foi maior em T1. Porém, a progressão da seca em 2015-2016 afetou negativamente o crescimento em altura e as trocas gasosas dos brotos de todos os tratamentos. Além disso, foi observado um aumento de cerca de 37% na eficiência intrínseca do uso da água. Quanto ao desempenho fotoquímico, não foram observadas alterações. Portanto, o estresse hídrico promoveu efeito negativo no crescimento da brotação e afetou características relacionadas à fotossíntese das brotações de B. excelsa, independentemente do número de brotações por cepa.(AU)

Impact of Brazil Nut (Bertholletia excelsa, H.B.K.) Supplementation on Body Composition, Blood Pressure, and the Vascular Reactivity of Wistar Rats When Submitted to a Hypersodium Diet.

Introdution: Endothelium integrity is a key that maintains vascular homeostasis but it can suffer irreversible damage by blood pressure changes, reflecting an imbalance in the maintenance of vascular homeostasis.Objective: The aim of this study was to investigate the impact of Brazil nut (Bertholletia excelsa, H.B.K.) (BN) supplementation (10% in chow, wt/wt) on the vascular reactivity of Wistar rats during chronic exposure to a sodium overload (1% in water).Methods: First, male Wistar rats were allocated into two groups: Control Group (CG) and the Hypersodic Group (HG) for 4 weeks. Afterward, the CG was divided into the Brazil Nut Group (BNG) and the HG Group into the Hypersodic Brazil Nut Group (HBNG) for a further 8 weeks, totaling 4 groups. Blood pressure was measured during the protocol. At the end of the protocol, the vascular reactivity procedure was performed. Glucose, lipid profile, lipid peroxidation, and platelet aggregation were analyzed in the serum. Body composition was determined by the carcass technique.Results: The groups that were supplemented with the BN chow presented less body mass gain and body fat mass, together with lower serum glucose levels. The HG Group presented an increase in blood pressure and a higher platelet aggregation, while the BN supplementation was able to blunt this effect. The HG Group also showed an increase in contractile response that was phenylephrine-induced and a decrease in maximum relaxation that was acetylcholine-induced when compared to the other groups.Conclusion: The BN supplementation was able to prevent an impaired vascular function in the early stages of arterial hypertension, while also improving body composition, serum glucose, and platelet aggregation.

Comparative models disentangle drivers of fruit production variability of an economically and ecologically important long-lived Amazonian tree.

Trees in the upper canopy contribute disproportionately to forest ecosystem productivity. The large, canopy-emergent Bertholletia excelsa also supports a multimillion-dollar commodity crop (Brazil nut), harvested almost exclusively from Amazonian forests. B. excelsa fruit production, however is extremely variable within populations and years, destabilizing local harvester livelihoods and the extractive economy. To understand this variability, data were collected in Acre, Brazil over 10 years at two sites with similar climate and forest types, but different fruit production levels, despite their proximity (~ 30 km). One site consistently produced more fruit, showed less individual- and population-level variability, and had significantly higher soil P and K levels. The strongest predictor of fruit production was crown area. Elevation and sapwood area also significantly impacted fruit production, but effects differed by site. While number of wet days and dry season vapor pressure prior to flowering were significant production predictors, no climatic variables completely captured annual observed variation. Trees on the site with higher available P and K produced nearly three times more fruits, and appeared more resilient to prolonged drought and drier atmospheric conditions. Management activities, such as targeted fertilization, may shield income-dependent harvesters from expected climate changes and production swings, ultimately contributing to conservation of old growth forests where this species thrives.

Contemporary pollen and seed dispersal in natural populations of Bertholletia excelsa (Bonpl.).

Due to the nutritional content and commercial value of its seeds, Bertholletia excelsa is one of the most important species exploited in the Amazon region. The species is hermaphroditic, insect pollinated, and its seeds are dispersed by barochory and animals. Because the fruit set is dependent on natural pollinator activity, gene flow plays a key role in fruit production. However, to date, there have been no studies on pollen and seed flow in natural populations of B. excelsa. Herein, we used microsatellite loci and parentage analysis to investigate the spatial genetic structure (SGS), realized pollen and seed dispersal, and effective pollen dispersal for two B. excelsa populations in the Brazilian Amazon forest. Two plots were established in natural forests from which adults, juveniles, and seeds were sampled. Realized and effective pollen flow was greater than realized seed flow. The distance of realized pollen dispersal ranged from 36 to 2060 m, and the distance of realized seed dispersal ranged from 30 to 1742 m. Both pollen and seeds showed a dispersal pattern of isolation by distance, indicating a high frequency of mating among near-neighbor trees and seed dispersal near to mother trees. Both populations present SGS up to 175 m, which can be explained by isolation by distance pollen and seed dispersal patterns. Our results suggested that fragmentation of these forest populations may result in a significant decrease in gene flow, due to the isolation by distance pollen and seed dispersal patterns.

Stereoscopy and scanning electron microscopy of Brazil nut (Bertholletia excelsa H.B.K.) shell, brown skin, and edible part: part one--healthy nut.

UNLABELLED: In this article, tissue layers and cells characteristics of the Brazil nut (Bertholletia excelsa H.B.K.) shell (tegument), brown skin (testae), and edible part (cotyledons) were identified by stereoscopy (SM) and scanning electron microscopies (SEM). (a) The shell (a lignin rich, protective wall) varies in thickness throughout the nut structure and comprises different tissue types (total 3)/texture (hard/mid-hard/soft), layers (2 to 5), colors (light to dark brown and white to cream), cell shape (amorphous/flattened on both surfaces; polygonal and cylindrical with thick, porous primary and secondary wall in cross-section), and vascular distribution (helically and polyedrical thickened vessels at soft tissue and locule/channel structures). These variations are observed either in the shell faces, face corners, nut tips, or locule in testae. (b) The brown skin (shell nut part linked to both the shell and edible part) is made of flattened irregular-shaped parenchymal cells distributed in several layers with more flexible fibrous, thinner wall tissue than shell. It has both rough and smooth shiny texture on the upper and lower surfaces, respectively. However, the nut (c) edible part, that is the nut storage tissue, shows several different tissue/cell layers starting from epidermis (double/triple cells sequence of round and palisade shapes) layer-the endosperm tissue. The parenchymal tissues show cells of irregular shape with small and larger sizes distributed in regular and randomly layers, respectively, separated by a short meristem tissue layer. The cortex cells increase in size as they approach the cotyledons junction. The Brazil nut part's tissue layers and cells were identified by the SM and SEM microscopy methods applied, which provides knowledge for further understanding of nut alterations that may occur either in the forest or during the factory processing. PRACTICAL APPLICATION: Knowledge about the characteristics and nature of the waste woody tissues from the Brazil nut factories is of interest for potential applications in the industry. Understanding the nut tissues and cells structures helps in judging how much whole nut edible part gets spoiled/deteriorated (either raw or processed), for further development of procedures to prevent and/or control such spoiling/deterioration for achieving nut quality and safety (to be discussed in Part Two).

Anthropogenic landscape in southeastern Amazonia: contemporary impacts of low-intensity harvesting and dispersal of Brazil nuts by the Kayapó Indigenous people.

Brazil nut, the Bertholletia excelsa seed, is one of the most important non-timber forest products in the Amazon Forest and the livelihoods of thousands of traditional Amazonian families depend on its commercialization. B. excelsa has been frequently cited as an indicator of anthropogenic forests and there is strong evidence that past human management has significantly contributed to its present distribution across the Amazon, suggesting that low levels of harvesting may play a positive role in B. excelsa recruitment. Here, we evaluate the effects of Brazil nut harvesting by the Kayapó Indigenous people of southeastern Amazonia on seedling recruitment in 20 B. excelsa groves subjected to different harvesting intensities, and investigated if management by harvesters influences patterns of B. excelsa distribution. The number of years of low-intensity Brazil nut harvesting by the Kayapó over the past two decades was positively related to B. excelsa seedling density in groves. One of the mechanisms behind the higher seedling density in harvested sites seems to be seed dispersal by harvesters along trails. The Kayapó also intentionally plant B. excelsa seeds and seedlings across their territories. Our results show not only that low-intensity Brazil nut harvesting by the Kayapó people does not reduce recruitment of seedlings, but that harvesting and/or associated activities conducted by traditional harvesters may benefit B. excelsa beyond grove borders. Our study supports the hypothesis that B. excelsa dispersal throughout the Amazon was, at least in part, influenced by indigenous groups, and strongly suggests that current human management contributes to the maintenance and formation of B. excelsa groves. We suggest that changes in Brazil nut management practices by traditional people to prevent harvesting impacts may be unnecessary and even counterproductive in many areas, and should be carefully evaluated before implementation.

Tradeoffs in basal area growth and reproduction shift over the lifetime of a long-lived tropical species.

Understanding of the extent to which reproductive costs drive growth largely derives from reproductively mature temperate trees in masting and non-masting years. We modeled basal area increment (BAI) and explored current growth-reproduction tradeoffs and changes in such allocation over the life span of a long-lived, non-masting tropical tree. We integrated rainfall and soil variables with data from 190 Bertholletia excelsa trees of different diameter at breast height (DBH) sizes, crown characteristics, and liana loads, quantifying BAI and reproductive output over 4 and 6 years, respectively. While rainfall explains BAI in all models, regardless of DBH class or ontogenic stage, light (based on canopy position and crown form) is most critical in the juvenile (5 cm ≤ DBH < 50 cm) phase. Suppressed trees are only present as juveniles and grow ten times slower (1.45 ± 2.73 m(2) year(-1)) than trees in dominant and co-dominant positions (13.25 ± 0.82 and 12.90 ± 1.35 m(2) year(-1), respectively). Additionally, few juvenile trees are reproductive, and those that are, demonstrate reduced growth, as do reproductive trees in the next 50 to 100 cm DBH class, suggesting growth-reproduction tradeoffs. Upon reaching the canopy, however, and attaining a sizeable girth, this pattern gradually shifts to one where BAI and reproduction are influenced independently by variables such as liana load, crown size and soil properties. At this stage, BAI is largely unaffected by fruit production levels. Thus, while growth-reproduction tradeoffs clearly exist during early life stages, effects of reproductive allocation diminish as B. excelsa increases in size and maturity.