State University of Norte Fluminense

Wood density is a critical control on tree biomass, so poor understanding of its spatial variation can lead to large and systematic errors in forest biomass estimates and carbon maps. The need to understand how and why wood density varies is especially critical in tropical America where forests have exceptional species diversity and spatial turnover in composition. As tree identity and forest composition are challenging to estimate remotely, ground surveys are essential to know the wood density of trees, whether measured directly or inferred from their identity. Here, we assemble an extensive dataset of variation in wood density across the most forested and tree-diverse continent, examine how it relates to spatial and environmental variables, and use these relationships to predict spatial variation in wood density over tropical and sub-tropical South America. Our analysis refines previously identified east-west Amazon gradients in wood density, improves them by revealing fine-scale variation, and extends predictions into Andean, dry, and Atlantic forests. The results halve biomass prediction errors compared to a naïve scenario with no knowledge of spatial variation in wood density. Our findings will help improve remote sensing-based estimates of aboveground biomass carbon stocks across tropical South America.

Anthropogenic solid residues are a serious environmental issue, affecting both terrestrial and aquatic ecosystems. Birds are particularly vulnerable to waste exposure, as they can interact with it through ingestion, entanglement, or by incorporating residues into their nests. The present study aimed to investigate the occurrence of anthropogenic residues in bird nests and how socio-environmental parameters affect nest anthropogenic contamination within and outside coastal protected areas. The results showed a widespread occurrence of anthropogenic residues in nests of 10 out of 17 bird species studied. Specifically, in nests of Great Kiskadee Pitangus sulphuratus a high contamination frequency (95 %) was verified. In the Generalized Linear Model urbanization levels and vegetation cover assessed using Human Modification Metric (HMc) and the Normalized Difference Vegetation Index (NDVI) did not have statistically significant effects on the presence of anthropogenic residues in bird nests. Similarly, nest location (inside or outside protected areas boundaries) and substrate type (natural or artificial) were not related to contamination level. Therefore, our results suggest that anthropogenic residues are already ubiquitous even within less anthropized areas. Such findings underscore the urgent need for enhanced waste management strategies to mitigate the negative impacts of anthropogenic waste on wildlife and local ecosystems, particularly in protected areas.

MgO-SiO2 cement was produced by combined calcination of MgCO3 and kaolin as raw materials, at a MgCO3/ kaolin mass ratio of 3.0 and 800 degrees C for 45 min. Separate calcination of MgCO3 and kaolin was also conducted under the same conditions. Raw materials were characterized based on their chemical composition, bulk density, particle size distribution, XRD, FTIR, and BET specific surface area, and the MgO-SiO2 cement produced was analyzed using XRD, FTIR, SEM/EDS, BET specific surface area, and particle size distribution. Pastes were produced to characterize microstructure and the reaction process (XRD, FTIR, TGA, isothermal calorimetry, chemical shrinkage, and SEM/EDS), and mortars to assess compressive strength. The results of BET and SEM/EDS analyses of the cements confirmed that combined calcination increased particle adhesion. Microstructural analyses of pastes after 28 days of curing at 25 degrees C showed the formation of a dense matrix of M-A-S-H reaction product, with aluminum incorporated into the M-A-S-H structure; brucite and hydrotalcite were also generated after the reaction process. Paste reaction results demonstrated that combined calcination produced cement with a higher degree of reaction after 72 h at 25 degrees C. The highest compressive strength (42.0 MPa) in mortars obtained by combined calcination was recorded after 28 days of curing at 25 degrees C, 223 % higher than that of separately calcined cement (13.0 MPa). As such, this study successfully applied combined calcination to produce a more strength MgO-SiO2 cement.

Auxin biosynthesis and transport are critical processes for in vitro tissue culture development, but the regulatory responses associated with these processes are still poorly understood in plants. We investigated the role of auxin transport during somatic embryo differentiation in sugarcane callus using an auxin transport inhibitor through a high-throughput proteomic approach. Four concentrations of 2,3,5-triiodobenzoic acid (TIBA 0, 1, 10, and 100 µM) were tested on sugarcane embryogenic callus during the pre-maturation phase. Treatment with 100 µM TIBA inhibited the differentiation of embryogenic callus into somatic embryos. Then, embryogenic callus from control and 100 µM TIBA treatments were compared via proteomic analysis. A total of 1221 proteins were found, of which 740 were differentially accumulated (DAP) in the 100 µM TIBA/Control comparison. Among the DAPs, 33 were unique to the control treatment, 31 were unique to the 100 µM TIBA pre-maturation treatment, and 415 down-regulated and 261 up-regulated. Inhibition of auxin transport impaired the accumulation and predicted protein interactions involved in embryonic development, ubiquitination, and energy metabolism. The concentrations of spermidine synthase and spermidine were reduced, suggesting an association between auxin and polyamines during development. The down-regulation of the proteins chaperone BOBBER1, Cullin-associated NEDD8-dissociated protein 1, and Receptor-like kinase TMK2 could be associated with auxin responses and the predicted interactions between proteasome members found during the differentiation of somatic embryos. These new findings demonstrate the role of auxin transport in downstream responses during somatic embryo differentiation and open new avenues for exploring the potential of sugarcane for biotechnological purposes.

Both, Serendipita indica and AMF, show promise as sustainable biofertilizers for reforestation, improving nutrient uptake and stress tolerance, despite contrasting effects on photosynthetic capacity and biomass allocation. Reclaiming degraded areas is essential for biodiversity conservation and enhancing ecosystem services enhancement, especially when using native species. This study investigated Schinus terebinthifolius Raddi, a native Brazilian species, and its compatibility with plant growth-promoting microorganisms (PGPM), including an endophytic fungus (Serendipita indica) and a consortium of arbuscular mycorrhizal fungi (AMF), to identify effective strategies for reforestation in nutrient-poor environments. We observed growth stimulation by both PGPMs; however, S. indica primarily enhanced root weight, whereas AMF improved shoot weight. S. indica’s positive effects on root systems could be attributed to increased auxin levels and altered root architecture, which are critical for seedling establishment in reforestation programs. In terms of nutritional status, both treatments increased the content of most nutrients, with higher micronutrient contents in the shoots and higher macronutrient content in roots of inoculated plants. Despite AMF’s role in enhancing photosynthesis, plants inoculated with these fungi showed reduced photosynthetic capacity traits, possibly due to lower leaf nitrogen content. The proteomic analysis of Schinus terebinthifolius leaf extracts revealed that, despite the upregulation of several proteins associated with the photosynthetic apparatus in response to S. indica treatment, no enhancement in photosynthetic capacity was observed. We also found several proteins related to oxidative stress in plants inoculated with both fungi, indicating a greater tolerance to adverse environmental conditions. These findings underscore the potential of both, S. indica and AMF, as sustainable alternatives to chemical fertilizers in reforestation efforts, enhancing seedling quality and survival in nutrient-poor soils.