Autonomous self-burying seed carriers for aerial seeding.

Aerial seeding can quickly cover large and physically inaccessible areas1 to improve soil quality and scavenge residual nitrogen in agriculture2, and for postfire reforestation3-5 and wildland restoration6,7. However, it suffers from low germination rates, due to the direct exposure of unburied seeds to harsh sunlight, wind and granivorous birds, as well as undesirable air humidity and temperature1,8,9. Here, inspired by Erodium seeds10-14, we design and fabricate self-drilling seed carriers, turning wood veneer into highly stiff (about 4.9 GPa when dry, and about 1.3 GPa when wet) and hygromorphic bending or coiling actuators with an extremely large bending curvature (1,854 m-1), 45 times larger than the values in the literature15-18. Our three-tailed carrier has an 80% drilling success rate on flat land after two triggering cycles, due to the beneficial resting angle (25°-30°) of its tail anchoring, whereas the natural Erodium seed's success rate is 0%. Our carriers can carry payloads of various sizes and contents including biofertilizers and plant seeds as large as those of whitebark pine, which are about 11 mm in length and about 72 mg. We compare data from experiments and numerical simulation to elucidate the curvature transformation and actuation mechanisms to guide the design and optimization of the seed carriers. Our system will improve the effectiveness of aerial seeding to relieve agricultural and environmental stresses, and has potential applications in energy harvesting, soft robotics and sustainable buildings.

Sub-continental-scale carbon stocks of individual trees in African drylands.

The distribution of dryland trees and their density, cover, size, mass and carbon content are not well known at sub-continental to continental scales1-14. This information is important for ecological protection, carbon accounting, climate mitigation and restoration efforts of dryland ecosystems15-18. We assessed more than 9.9 billion trees derived from more than 300,000 satellite images, covering semi-arid sub-Saharan Africa north of the Equator. We attributed wood, foliage and root carbon to every tree in the 0-1,000 mm year-1 rainfall zone by coupling field data19, machine learning20-22, satellite data and high-performance computing. Average carbon stocks of individual trees ranged from 0.54 Mg C ha-1 and 63 kg C tree-1 in the arid zone to 3.7 Mg C ha-1 and 98 kg tree-1 in the sub-humid zone. Overall, we estimated the total carbon for our study area to be 0.84 (±19.8%) Pg C. Comparisons with 14 previous TRENDY numerical simulation studies23 for our area found that the density and carbon stocks of scattered trees have been underestimated by three models and overestimated by 11 models, respectively. This benchmarking can help understand the carbon cycle and address concerns about land degradation24-29. We make available a linked database of wood mass, foliage mass, root mass and carbon stock of each tree for scientists, policymakers, dryland-restoration practitioners and farmers, who can use it to estimate farmland tree carbon stocks from tablets or laptops.

Plant functional traits have globally consistent effects on competition.

Phenotypic traits and their associated trade-offs have been shown to have globally consistent effects on individual plant physiological functions, but how these effects scale up to influence competition, a key driver of community assembly in terrestrial vegetation, has remained unclear. Here we use growth data from more than 3 million trees in over 140,000 plots across the world to show how three key functional traits--wood density, specific leaf area and maximum height--consistently influence competitive interactions. Fast maximum growth of a species was correlated negatively with its wood density in all biomes, and positively with its specific leaf area in most biomes. Low wood density was also correlated with a low ability to tolerate competition and a low competitive effect on neighbours, while high specific leaf area was correlated with a low competitive effect. Thus, traits generate trade-offs between performance with competition versus performance without competition, a fundamental ingredient in the classical hypothesis that the coexistence of plant species is enabled via differentiation in their successional strategies. Competition within species was stronger than between species, but an increase in trait dissimilarity between species had little influence in weakening competition. No benefit of dissimilarity was detected for specific leaf area or wood density, and only a weak benefit for maximum height. Our trait-based approach to modelling competition makes generalization possible across the forest ecosystems of the world and their highly diverse species composition.

Peroxidase evolution in white-rot fungi follows wood lignin evolution in plants.

A comparison of sequenced Agaricomycotina genomes suggests that efficient degradation of wood lignin was associated with the appearance of secreted peroxidases with a solvent-exposed catalytic tryptophan. This hypothesis is experimentally demonstrated here by resurrecting ancestral fungal peroxidases, after sequence reconstruction from genomes of extant white-rot Polyporales, and evaluating their oxidative attack on the lignin polymer by state-of-the-art analytical techniques. Rapid stopped-flow estimation of the transient-state constants for the 2 successive one-electron transfers from lignin to the peroxide-activated enzyme (k2app and k3app ) showed a progressive increase during peroxidase evolution (up to 50-fold higher values for the rate-limiting k3app ). The above agreed with 2-dimensional NMR analyses during steady-state treatments of hardwood lignin, showing that its degradation (estimated from the normalized aromatic signals of lignin units compared with a control) and syringyl-to-guaiacyl ratio increased with the enzyme evolutionary distance from the first peroxidase ancestor. More interestingly, the stopped-flow estimations of electron transfer rates also showed how the most recent peroxidase ancestors that already incorporated the exposed tryptophan into their molecular structure (as well as the extant lignin peroxidase) were comparatively more efficient at oxidizing hardwood (angiosperm) lignin, while the most ancestral "tryptophanless" enzymes were more efficient at abstracting electrons from softwood (conifer) lignin. A time calibration of the ancestry of Polyporales peroxidases localized the appearance of the first peroxidase with a solvent-exposed catalytic tryptophan to 194 ± 70 Mya, coincident with the diversification of angiosperm plants characterized by the appearance of dimethoxylated syringyl lignin units.

A fast and low-cost approach for the discrimination of commercial aged cachaças using synchronous fluorescence spectroscopy and multivariate classification.

BACKGROUND: Cachaça is the distilled beverage typical of Brazil and can be subjected to the aging process in wooden barrels. In addition to oak barrels, cachaça is also aged in barrels of different Brazilian native woods, resulting in a wide variety of its sensory characteristics. In this work, 172 cachaças aged in bálsamo, jequitibá, oak, and umburana barrels were analyzed by synchronous fluorescence spectroscopy and by the classification methods of principal component analysis and partial least squares discriminant analysis. Spectra were preprocessed by the first derivative by Savitzky-Golay smoothing, using a filter width and polynomial order determined through face-centered central composite designs. Multivariate analysis was realized using the spectra recorded at different wavelength differences, and models were compared by the classification errors in the test sets. RESULTS: The principal component analysis applied to the synchronous fluorescence spectra presented a tendency of separation by the wood used in the aging process, and the partial least squares discriminant analysis model constructed using the fluorescence spectra recorded at a wavelength difference of 30 nm provided better performance parameters (efficiency 91-97%, sensitivity 81-100%, and specificity 91-100%). CONCLUSION: Synchronous fluorescence spectroscopy offers a promising approach for the classification of cachaças aged in bálsamo, oak, jequitibá, and umburana barrels, and the discriminant model can be used for routine analysis as a screening method. © 2022 Society of Chemical Industry.

Traces under nails in clinical forensic medicine: not just DNA.

When dealing with complex crimes such as rape and assault, every trace takes on an essential role. The hands are often the only means of defence and offence for the victim as well as a frequent area of contact with the environment; fingernails of a victim are a well-known possible source of DNA of the aggressor; nevertheless, they are more rarely treated as an area of interest for non-genetic material, particularly on living victims. The hyponychium, because of its physiological protective function, lends itself ideally to retaining different kinds of traces representative of an environment or various products and substrates that could shed light on the environment and objects involved in the event. We therefore tested how far this capability of the hyponychium could go by simulating the dynamics of contamination of the nail through scratching on different substrates (brick and mortar, painted wood, ivy leaves, cotton and woollen fabric, soil) and persistence of any contaminant at different time intervals. We have thus shown how these traces may remain in the living for up to 24 h after the event using inexpensive and non-destructive techniques such as the episcopic and optical microscope.

Long-term decline of the Amazon carbon sink.

Atmospheric carbon dioxide records indicate that the land surface has acted as a strong global carbon sink over recent decades, with a substantial fraction of this sink probably located in the tropics, particularly in the Amazon. Nevertheless, it is unclear how the terrestrial carbon sink will evolve as climate and atmospheric composition continue to change. Here we analyse the historical evolution of the biomass dynamics of the Amazon rainforest over three decades using a distributed network of 321 plots. While this analysis confirms that Amazon forests have acted as a long-term net biomass sink, we find a long-term decreasing trend of carbon accumulation. Rates of net increase in above-ground biomass declined by one-third during the past decade compared to the 1990s. This is a consequence of growth rate increases levelling off recently, while biomass mortality persistently increased throughout, leading to a shortening of carbon residence times. Potential drivers for the mortality increase include greater climate variability, and feedbacks of faster growth on mortality, resulting in shortened tree longevity. The observed decline of the Amazon sink diverges markedly from the recent increase in terrestrial carbon uptake at the global scale, and is contrary to expectations based on models.

Various effects of the expression of the xyloglucanase gene from Penicillium canescens in transgenic aspen under semi-natural conditions.

BACKGROUND: Recombinant carbohydrases genes are used to produce transgenic woody plants with improved phenotypic traits. However, cultivation of such plants in open field is challenging due to a number of problems. Therefore, additional research is needed to alleviate them. RESULTS: Results of successful cultivation of the transgenic aspens (Populus tremula) carrying the recombinant xyloglucanase gene (sp-Xeg) from Penicillium canescens in semi-natural conditions are reported in this paper for the first time. Change of carbohydrate composition of wood was observed in transgenic aspens carrying the sp-Xeg gene. The transformed transgenic line Xeg-2-1b demonstrated accelerated growth and increased content of cellulose in wood of trees growing in both greenhouse and outside in comparison with the control untransformed line Pt. The accelerated growth was observed also in the transgenic line Xeg-1-1c. Thicker cell-wall and longer xylem fiber were also observed in both these transgenic lines. Undescribed earlier considerable reduction in the wood decomposition rate of the transgenic aspen stems was also revealed for the transformed transgenic lines. The decomposition rate was approximately twice as lower for the transgenic line Xeg-2-3b in comparison with the control untransformed line Pt. CONCLUSION: A direct dependence of the phenotypic and biochemical traits on the expression of the recombinant gene sp-Xeg was demonstrated. The higher was the level of the sp-Xeg gene expression, the more pronounced were changes in the phenotypic and biochemical traits. All lines showed phenotypic changes in the leave traits. Our results showed that the plants carrying the recombinant sp-Xeg gene do not demonstrate a decrease in growth parameters in semi-natural conditions. In some transgenic lines, a change in the carbohydrate composition of the wood, an increase in the cell wall thickness, and a decrease in the rate of decomposition of wood were observed.

Fiber fractionation to understand the effect of mechanical refining on fiber structure and resulting enzymatic digestibility of biomass.

Mechanical refining results in fiber deconstruction and modifications that enhance enzyme accessibility to carbohydrates. Further understanding of the morphological changes occurring to biomass during mechanical refining and the impacts of these changes on enzymatic digestibility is necessary to maximize yields and reduce energy consumption. Although the degree of fiber length reduction relative to fibrillation/delamination can be impacted by manipulating refining variables, mechanical refining of any type (PFI, disk, and valley beater) typically results in both phenomena. Separating the two is not straightforward. In this study, fiber fractionation based on particle size performed after mechanical refining of high-lignin pulp was utilized to successfully elucidate the relative impact of fibrillation/delamination and fiber cutting phenomena during mechanical refining. Compositional analysis showed that fines contain significantly more lignin than larger size fractions. Enzymatic hydrolysis results indicated that within fractions of uniform fiber length, fibrillation/delamination due to mechanical refining increased enzymatic conversion by 20-30 percentage points. Changes in fiber length had little effect on digestibility for fibers longer than ~0.5 mm. However, the digestibility of the fines fractions was high for all levels of refining even with the high-lignin content.

UPLC-ESI-MS/MS-Based Widely Targeted Metabolomics Analysis of Wood Metabolites in Teak (Tectona grandis).

The properties of teak wood, such as natural durability and beautiful color, are closely associated with wood extractives. In order to further understand the performance differences between teak heartwood and sapwood, we analyzed the chemical components of extractives from 12 wood samples using an ultrahigh-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS)-based metabolomics approach. In total, 691 metabolites were identified, and these were classified into 17 different categories. Clustering analysis and principal component analysis of metabolites showed that heartwood samples could be clearly separated from sapwood samples. Differential metabolite analysis revealed that the levels of primary metabolites, including carbohydrates, amino acids, lipids, and nucleotides, were significantly lower in the heartwood than in the sapwood. Conversely, many secondary metabolites, including flavonoids, phenylpropanoids, and quinones, had higher levels in the heartwood than in the sapwood. In addition, we detected 16 specifically expressed secondary metabolites in the heartwood, the presence of which may correlate with the durability and color of teak heartwood. Our study improves the understanding of differential metabolites between sapwood and heartwood of teak and provides a reference for the study of heartwood formation.

Sampling strategy and climatic implication of tree-ring cellulose oxygen isotopes of Hippophae tibetana and Abies georgei on the southeastern Tibetan Plateau.

The tree-ring cellulose oxygen isotopes (δ18O) for four trees of Hippophae tibetana and four trees of Abies georgei growing in different locations around the terminal moraine in Xincuo from 1951 to 2010 were measured to explore its potential for reconstructing climatic variations in the southeastern Tibetan Plateau. The mean and standard deviation of tree-ring δ18O at different heights do not have significant differences, and there are no significant differences in the mean and standard deviation of tree-ring δ18O between trees near the brook and trees at the top of moraine, indicating that we can collect samples for tree-ring δ18O analysis regardless of sampling heights and that the micro-environment does not affect tree-ring δ18O significantly. The mean inter-series correlations of cellulose δ18O for A. georgei/H. tibetana are 0.84/0.93, and the correlation between δ18O for A. georgei and H. tibetana is 0.92. The good coherence between inter-tree and inter-species cellulose δ18O demonstrates the possibility of using different species to develop a long chronology. Correlation analysis between tree-ring δ18O and climate parameters revealed that δ18O for A. georgei/H. tibetana had negative correlations (r = -0.62/r = -0.69) with relative humidity in July-August, and spatial correlation revealed that δ18O for A. georgei/H. tibetana reflected the regional Standardized Precipitation Evapotranspiration Index (29°-32° N, 88°-98° E). In addition, tree-ring δ18O in Xincuo has a significant correlation with tree-ring δ18O in Bhutan. The results indicate that cellulose δ18O for A. georgei and H. tibetana in Xincuo is a good proxy for the regional hydroclimate.

Nanocellulose-Reinforced Polyurethane for Waterborne Wood Coating.

With the enhancement of people's environmental awareness, waterborne polyurethane (PU) paint-with its advantages of low release of volatile organic compounds (VOCs), low temperature flexibility, acid and alkali resistance, excellent solvent resistance and superior weather resistance-has made its application for wood furniture favored by the industry. However, due to its lower solid content and weak intermolecular force, the mechanical properties of waterborne PU paint are normally less than those of the traditional solvent-based polyurethane paint, which has become the key bottleneck restricting its wide applications. To this end, this study explores nanocellulose derived from biomass resources by the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidation method to reinforce and thus improve the mechanical properties of waterborne PU paint. Two methods of adding nanocellulose to waterborne PU-chemical addition and physical blending-are explored. Results show that, compared to the physical blending method, the chemical grafting method at 0.1 wt% nanocellulose addition results in the maximum improvement of the comprehensive properties of the PU coating. With this method, the tensile strength, elongation at break, hardness and abrasion resistance of the waterborne PU paint increase by up to 58.7%, ~55%, 6.9% and 3.45%, respectively, compared to the control PU; while the glossiness and surface drying time were hardly affected. Such exploration provides an effective way for wide applications of water PU in the wood industry and nanocellulose in waterborne wood coating.

Physical-mechanical characterization of two amazon woods coming from the second cutting cycle.

Due to changes in the Amazon forest dynamics after the first cutting cycle, non exploited species become dominant in the forest. The lack of technological knowledge makes it hard to commercialize these woods, making the understanding of their physical-mechanical properties a fundamental step to properly define their applications. This study aimed to characterize physically and mechanically the wood of Pseudopiptadenia psilostachya and Eschweilera ovata from the second cutting cycle of the Tapajós National Forest, intending to commercially promote and to identify usages for them, as well as to evaluate the viability of replacement of highly commercialized species. The tests were performed accordingly to the Brazilian standard NBR 7190. P. psilostachya, presented bulk density of 0.683 g.cm-3, medium levels of shrinkage and anisotropy, as well as medium hardness (7366 N) and high strength on compression parallel to grain (71.63 MPa) and on static bending (103.9 MPa). It was generally superior to Euxylophora paraensis, but inferior when compared to Bagasssa guianensis and Apuleia leiocarpa, with possibilities to replace these three species. E. ovata, on the other hand, presented bulk density of 0.798 g.cm-3, high shrinkage and anisotropy values, but high values for hardness (12089 N) and strength on compression parallel to grain (68.67 MPa) and on static bending (127.1 MPa). This species exhibited, in general, similarities with Mezilaurus itauba, although it is a little inferior in relation to Hymenaea sp. and Astronium lecointei. Both species, P. psilostachya and E. ovata fit in the highest strength class described on the Brazilian Standard NBR7190, C60. By means of the results found, it was concluded that although the species studied were unknown, they presented timber with enough quality to replace some Amazon timber species widely commercialized on both national and international market.

Heartwood and sapwood in eucalyptus trees: non-conventional approach to wood quality.

This study evaluated the quality of heartwood and sapwood from mature trees of three species of Eucalyptus, by means of the qualification of their proportion, determination of basic and apparent density using non-destructive attenuation of gamma radiation technique and calculation of the density uniformity index. Six trees of each species (Eucalyptus grandis - 18 years old, Eucalyptus tereticornis - 35 years old and Corymbia citriodora - 28 years old) were used in the experimental program. The heartwood and sapwood were delimited by macroscopic analysis and the calculation of areas and percentage of heartwood and sapwood were performed using digital image. The uniformity index was calculated following methodology which numerically quantifies the dispersion of punctual density values of the wood around the mean density along the radius. The percentage of the heartwood was higher than the sapwood in all species studied. The density results showed no statistical difference between heartwood and sapwood. Differently from the density results, in all species studied there was statistical differences between uniformity indexes for heartwood and sapwood regions, making justifiable the inclusion of the density uniformity index as a quality parameter for Eucalyptus wood.

Functional network analysis of genes differentially expressed during xylogenesis in soc1ful woody Arabidopsis plants.

Many plant genes are known to be involved in the development of cambium and wood, but how the expression and functional interaction of these genes determine the unique biology of wood remains largely unknown. We used the soc1ful loss of function mutant - the woodiest genotype known in the otherwise herbaceous model plant Arabidopsis - to investigate the expression and interactions of genes involved in secondary growth (wood formation). Detailed anatomical observations of the stem in combination with mRNA sequencing were used to assess transcriptome remodeling during xylogenesis in wild-type and woody soc1ful plants. To interpret the transcriptome changes, we constructed functional gene association networks of differentially expressed genes using the STRING database. This analysis revealed functionally enriched gene association hubs that are differentially expressed in herbaceous and woody tissues. In particular, we observed the differential expression of genes related to mechanical stress and jasmonate biosynthesis/signaling during wood formation in soc1ful plants that may be an effect of greater tension within woody tissues. Our results suggest that habit shifts from herbaceous to woody life forms observed in many angiosperm lineages could have evolved convergently by genetic changes that modulate the gene expression and interaction network, and thereby redeploy the conserved wood developmental program.

Climate trends in the wood anatomy of Acacia sensu stricto (Leguminosae: Mimosoideae).

Background and Aims: This study investigates the structural diversity of the secondary xylem of 54 species of Acacia from four taxonomic sections collected across five climate regions along a 1200 km E-W transect from sub-tropical [approx. 1400 mm mean annual precipitation (MAP)] to arid (approx. 240 mm MAP) in New South Wales, Australia. Acacia sensu stricto ( s.s. ) is a critical group for understanding the effect of climate and phylogeny on the functional anatomy of wood. Methods: Wood samples were sectioned in transverse, tangential and radial planes for light microscopy and analysis. Key Results: The wood usually has thick-walled vessels and fibres, paratracheal parenchyma and uniseriate and biseriate rays, occasionally up to four cells wide. The greater abundance of gelatinous fibres in arid and semi-arid species may have ecological significance. Prismatic crystals in chambered fibres and axial parenchyma increased in abundance in semi-arid and arid species. Whereas vessel diameter showed only a small decrease from the sub-tropical to the arid region, there was a significant 2-fold increase in vessel frequency and a consequent 3-fold decrease in the vulnerability index. Conclusions: Although the underlying phylogeny determines the qualitative wood structure, climate has a significant influence on the functional wood anatomy of Acacia s.s. , which is an ideal genus to study the effect of these factors.

Evaluating climate signal recorded in tree-ring δ13 C and δ18 O values from bulk wood and α-cellulose for six species across four sites in the northeastern US.

RATIONALE: We evaluated the applicability of tree-ring δ13 C and δ18 O values in bulk wood - instead of the more time and lab-consuming α-cellulose δ13 C and δ18 O values, to assess climate and physiological signals across multiple sites and for six tree species along a latitudinal gradient (35°97'N to 45°20'N) of the northeastern United States. METHODS: Wood cores (n = 4 per tree) were sampled from ten trees per species. Cores were cross-dated within and across trees at each site, and for the last 30 years. Seven years, including the driest on record, were selected for this study. The δ13 C and δ18 O values were measured on two of the ten trees from the bulk wood and the α-cellulose. The offsets between materials in δ13 C and δ18 O values were assessed. Correlation and multiple regression analyses were used to evaluate the strength of the climate signal across sites. Finally the relationship between δ13 C and δ18 O values in bulk wood vs α-cellulose was analyzed to assess the consistency of the interpretation, in terms of CO2 assimilation and stomatal conductance, from both materials. RESULTS: We found offsets of 1.1‰ and 5.6‰ between bulk and α-cellulose for δ13 C and δ18 O values, respectively, consistent with offset values reported in the literature. Bulk wood showed similar or stronger correlations to climate parameters than α-cellulose for the investigated sites. In particular, temperature and vapor pressure deficit and standard precipitation-evaporation index (SPEI) were the most visible climate signals recorded in δ13 C and δ18 O values, respectively. For most of the species, there was no relationship between δ13 C and δ18 O values, regardless of the wood material considered. CONCLUSIONS: Extraction of α-cellulose was not necessary to detect climate signals in tree rings across the four investigated sites. Furthermore, the physiological information inferred from the dual isotope approach was similar for most of the species regardless of the material considered.