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Accurate wood identification is crucial for combatting the illegal logging and trade of forest products worldwide. However, certain challenges such as small specimen size, high wood density, and level of degradation can complicate the identification process. There is therefore a need to develop methods and use complementary techniques in forensic wood identification, particularly for difficult samples. This study utilized confocal laser scanning microscopy (CLSM) to detect and locate autofluorescence of axial parenchyma cells (APCs) to facilitate the identification of three challenging unknown wood specimens. These specimens posed difficulties for sectioning with a microtome due to brittleness, density, or small size constraints. CLSM results were compared with those from conventional light compound and stereomicroscopy. In our investigation, the three unknown wood samples were identified as Bobgunnia cf. fistuloides, Chlorocardium cf. rodiei, and Diphysa cf. carthagenensis. Specifically, CLSM confirmed the absence of apotracheal parenchyma in B. cf. fistuloides, which could not be determined using fluorescence stereomicroscopy. For D. cf. carthagenensis, CLSM’s fluorescence intensity highlighted axial parenchyma effectively, surpassing fluorescence stereomicroscopy. A notable advantage of our non-invasive CLSM method was its ability to examine smooth, unsectioned block surfaces, thereby enhancing preservation and ‘in-situ’ visualization of APCs. Our results combining autofluorescence and CLSM clearly offered superior resolution in observing APCs compared to traditional microscopy and can thus be applied for increasing confidence in wood species identification. [ABSTRACT FROM AUTHOR]

A newly-discovered endemic tree species of Melicope from Kaua'i, Hawaiian Islands, is described and illustrated with notes on its distribution, ecology, conservation status and phylogenetic placement. A modification to the existing key to Hawaiian Melicope is also provided. Melicope iolensis sp. nov. is a member of Stone's Megacarpa group having carpels connate at base, capsules 4-lobed and leaves usually opposite. The new species differs from its Hawaiian congeners by its unique combination of abaxially glabrate to pilose-pubescent leaves with petioles up to 70 mm long, ramiflorous and axillary inflorescences, sepals on staminate flowers 0.3–0.5 mm long, capsules with green and purple streaking, 10–14 mm wide and seeds 3–3.5 mm long. Since its discovery in 2021, 15 individuals have been documented within a single remote windward hanging valley below the Kawaikini Summit of Kaua'i. Melicope iolensis represents a new Critically Endangered (CR) single island endemic species in need of conservation. [ABSTRACT FROM AUTHOR]

Premise: Functional traits reflect species' responses to environmental variation and the breadth of their ecological niches. Fagus grandifolia and Oreomunnea mexicana have restricted distribution in upper montane cloud forests (1700–2000 m a.s.l.) in Mexico. These species were introduced into plantings at lower elevations (1200–1600 m a.s.l.) that have climates predicted for montane forests in 2050 and 2070. The aim was to relate morphological leaf traits to the ecological niche structure of each species. Methods: Leaf functional traits (leaf area, specific leaf area [SLA], thickness, and toughness) were analyzed in forests and plantings. Atmospheric circulation models and representative concentration pathways (RCPs: 2.6, 4.5, 8.5) were used to assess future climate conditions. Trait–niche relationships were analyzed by measuring the Mahalanobis distance (MD) from the forests and the plantings to the ecological niche centroid (ENC). Results: For both species, leaf area and SLA were higher and toughness lower in plantings at lower elevation relative to those in higher‐elevation forests, and thickness was similar. Leaf traits varied with distance from sites to the ENC. Forests and plantings have different environmental locations regarding the ENC, but forests are closer (MD 0.34–0.58) than plantings (MD 0.50–0.70) for both species. Conclusions: Elevation as a proxy for expected future climate conditions influenced the functional traits of both species, and trait patterns related to the structure of their ecological niches were consistent. The use of distances to the ENC is a promising approach to explore variability in species' functional traits and phenotypic responses in optimal versus marginal environmental conditions. [ABSTRACT FROM AUTHOR]

The role of arbuscular mycorrhizal fungi (AMF) and soil nematodes in primary production and plant nutrient uptake through plant-soil feedback in the Araucaria ecosystem remains poorly quantified. We aimed to understand the role of AMF and soil nematodes on Araucaria angustifolia using three phenological stages of this native plant species: adult/mature trees in field conditions (1st experiment), from germination to the seedling stage under in situ conditions (2nd experiment), and from the seedling to sapling stage under ex situ conditions (3rd experiment). In the field experiment, we determined soil biochemical properties and AMF and soil nematode community structure. Soil inoculum was collected in the 1st experiment. Throughout the 2nd experiment, we determined plant biomass production and plant P uptake. Finally, we determined root colonisation by AMF and root lesions by root-feeding nematodes and their relationship with plant biomass and plant P content in the 3rd experiment. At the high-quality site, there was significantly higher microbial respiration, microbial N and C biomass, soil pH, soil organic carbon, total nitrogen, and Olsen's P compared to the low-quality site. Both the in situ and ex situ stages were positively correlated with AMF diversity and negatively correlated with the abundance of root-feeding nematodes. Using structural equation modelling, we found evidence that root colonisation and root lesions were affected by AMF richness and soil nematodes. This study highlights the importance of considering the establishment of AMF and soil nematode communities, their correlation with soil quality, and Araucaria's phenological stages (germination, seedling, sapling, and adult trees), which can be influenced by soil inoculum. [ABSTRACT FROM AUTHOR]

Summary: Andean Walnut (Juglans neotropica Diels-Juglandaceae) is a long-lived, deciduous broadleaf Tropical Montane Cloud Forest (TMCF) tree species native to the Andes Cordillera; nevertheless, it has received limited attention for dendro-quantitative wood anatomical studies. Based on 70 increment cores from 50 Andean Walnut trees at two Peruvian TMCFs, two chronologies (from 1969 to 2020 and from 1964 to 2020) were developed. The xylem vessel parameters assessment allowed us to detect South American Monsoon System (SAMS) precipitation signals in the Andean Walnuts' wood. Dendro-wood anatomical features can be assessed within an annual growth ring, which allows for assessing intra-annual past and present wood anatomy-function relationships and its climate vulnerability. [ABSTRACT FROM AUTHOR]

Invasive exotic plant species plays a key role in changing symbionts' community composition and soil biochemical traits into invaded areas. Our aim was to figure out whether the P. taeda alters the AMF community and soil biochemical traits when compared with a natural ecosystem and an agroforestry system of the Southern Brazil. We found the highest values of litter deposition, total nitrogen, AMF richness, Shannon's diversity, Simpson's dominance, root colonization, and plant P content on plots with P. taeda. By using the structural equation modelling, we found that the P. taeda positively affected the abundance of C. claroideum, C. etunicatum, F. mosseae, and Glomus sp., root colonization, plant P content, and litter deposition, and negatively affected Olsen's available P, soil organic carbon, and microbial biomass carbon. The results of our study highlighted the importance of considering monostands of P. taeda with high AMF richness and Shannon's diversity. Thus, long-term experiments considering areas dominated by an invasive exotic plant species, and areas under an assisted forest regeneration (agroforestry systems) may exploit interesting results in subtropical conditions. [ABSTRACT FROM AUTHOR]

The role of soil biotic and abiotic factors in crucial soil functions such as primary production, organic matter dynamics, nutrient cycling, and soil biota community structure in the Araucaria ecosystem remains poorly quantified. We aimed to understand how the development of organic horizons, root growth, soil chemical properties, and the entire soil biota community affected the soil quality in even aged and monospecific Araucaria angustifolia plantations. We collected soil monoliths to describe layers of organic matter and the complex soil food web into these layers. We determined soil pH, soil moisture, total nitrogen, available P, and total organic carbon into each layer (litter, F-layer, H-layer, and A horizon), the biomass of fine roots, the community structure of soil biota, arbuscular mycorrhizal fungi, and nematodes, as well as the microbial biomass carbon. In the high-quality site, there was significantly higher organic matter formation, nutrient cycling (N and P), root growth, soil moisture, soil biota diversity, arbuscular mycorrhizal fungi, and nematodes evaluated by the microbial biomass carbon compared to the low-quality site. High-quality sites promote the development of organic horizons, root growth on superficial layers that provide plant nutrient release, the A horizon nutrient contents, and the entire soil biota community in monospecific Araucaria angustifolia plantations located on humid subtropical Cambisols. This creates a positive plant-soil feedback that maintains soil quality and increases primary production, nutrient cycling, and habitat and food for the soil food web. [ABSTRACT FROM AUTHOR]

The endemic ruil (Nothofagus alessandrii Espinosa) forest is one of the most endangered forest ecosystems in central Chile, where its regeneration is challenged by factors such as low seedling germination capacity and recently by fire. In this study, we sampled 36 plots (625 m2 each) within the very restricted distribution range of N. alessandrii and quantified regeneration of the species from seed after a catastrophic large-scale fire event in 2017. By means of logistic regression, Path analysis, and non-metric multidimensional scaling, we related ruil seedling regeneration with percentage vegetative cover, number of ruil individuals, richness of native species, density of seedlings of the introduced species Pinus radiata D. Don, and fire severity. Our results indicate that fire severity was the most important variable explaining the probability of regeneration of N. alessandrii. Seedling recruitment was present in 65% of the sites with low fire severity, but no recruitment was observed in sites severely burned by fire. The ecological implications of these findings suggest that after a high-severity fire, efforts to restore N. alessandrii should be concentrated on reforestation activities; however, in areas of low-severity burn, efforts must be focused on the management and protection of the new recruits. [ABSTRACT FROM AUTHOR]

Vegetation types alter soil ecosystems by changing soil fauna community activities and soil physical–chemical properties. However, it is unclear how tree species (natural forest, native and exotic tree plantations) promote changes in the soil ecosystem, and if these changes alter functional groups of soil fauna and ecosystem services. To determine the effects of five decades of old-field vegetation on soil ecosystems in the Brazilian Atlantic Forest, field sampling of three ecosystems (exotic tree species Pinus elliottii Engelm. plantation, endangered tree species Araucaria angustifolia (Bertol.) Kuntze plantation, and a natural ecosystem) were carried out, as well using bait-lamina tests and bioassays with collembolans, earthworms and seeds of Lactuca sativa L. Field sampling evaluated the soil fauna community and soil physical–chemical properties. The bait-lamina test in situ was carried out for 14-days to determine fauna feeding activity, and the bioassays evaluated the reproduction of Folsomia candida, the avoidance of Eisenia andrei, and germination of L. sativa in the soil from each ecosystem. The results are: (1) vegetation type altered the soil fauna community composition; (2) soil fauna feeding was reduced in the plantations compared to the natural ecosystem; (3) a physical barrier was created by recalcitrant litter that compromised fauna community structure and seed bank germination in situ; and, (4) changes in soil physical–chemical properties promoted decomposers. [ABSTRACT FROM AUTHOR]

How well ex situ living collections capture the genetic variation of their wild-source populations, is an efficient indicator for assessing the success of ex situ conservation. Here, we explore the origins and genetic representation of multiple species' ex situ living collections that have been established for 20–35 years. We only sampled the potential wild-source populations, which cover parts of the focal species’ natural distribution ranges. Using microsatellite loci, we compared the genetic diversity between ex situ and wild populations, and verified the wild-source populations of ex situ living collections for five endangered tree species (i.e., Davidia involucrata, Dipteronia sinensis, Tetracentron sinense, Cercidiphyllum japonicum, and Tapiscia sinensis). We found that the genetic diversity of ex situ populations is comparable to their wild-source populations for all five plant species. We detected weak genetic structure among ex situ and wild-source populations for each species. Our results suggested that ex situ living plant collections may have comparable genetic diversity compared with their corresponding wild-source populations. We recommend that additional ex situ collections from different maternal lines across ex situ institutions or the distribution range of the target species would contribute to high level of genetic representation of ex situ populations, and (2) complete collection records and optimal sampling strategies are required for effective ex situ plant conservation.

Beneficial plant-associated microorganisms, such as fungal endophytes, are key partners that normally improve plant survival under different environmental stresses. It has been shown that microorganisms from extreme environments, like those associated with the roots of Antarctica plants, can be good partners to increase the performance of crop plants and to restore endangered native plants. Nothofagus alessandrii and N. glauca, are among the most endangered species of Chile, restricted to a narrow and/or limited distributional range associated mainly to the Maulino forest in Chile. Here we evaluated the effect of the inoculation with a fungal consortium of root endophytes isolated from the Antarctic host plant Colobanthus quitensis on the ecophysiological performance [photosynthesis, water use efficiency (WUE), and growth] of both endangered tree species. We also, tested how Antarctic root-fungal endophytes could affect the potential distribution of N. alessandrii through niche modeling. Additionally, we conducted a transplant experiment recording plant survival on 2 years in order to validate the model. Lastly, to evaluate if inoculation with Antarctic endophytes has negative impacts on native soil microorganisms, we compared the biodiversity of fungi and bacterial in the rhizospheric soil of transplanted individuals of N. alessandrii inoculated and non-inoculated with fungal endophytes. We found that inoculation with root-endophytes produced significant increases in N. alessandrii and N. glauca photosynthetic rates, water use efficiencies and cumulative growth. In N. alessandrii, seedling survival was significantly greater on inoculated plants compared with non-inoculated individuals. For this species, a spatial distribution modeling revealed that, inoculation with root-fungal endophytes could potentially increase the current distributional range by almost threefold. Inoculation with root-fungal endophytes, did not reduce native rhizospheric microbiome diversity. Our results suggest that the studied consortium of Antarctic root-fungal endophytes improve the ecophysiological performance as well as the survival of inoculated trees and can be used as a biotechnological tool for the restoration of endangered tree species.

Beneficial plant-associated microorganisms, such as fungal endophytes, are key partners that normally improve plant survival under different environmental stresses. It has been shown that microorganisms from extreme environments, like those associated with the roots of Antarctica plants, can be good partners to increase the performance of crop plants and to restore endangered native plants. Nothofagus alessandrii and N. glauca , are among the most endangered species of Chile, restricted to a narrow and/or limited distributional range associated mainly to the Maulino forest in Chile. Here we evaluated the effect of the inoculation with a fungal consortium of root endophytes isolated from the Antarctic host plant Colobanthus quitensis on the ecophysiological performance [photosynthesis, water use efficiency (WUE), and growth] of both endangered tree species. We also, tested how Antarctic root-fungal endophytes could affect the potential distribution of N. alessandrii through niche modeling. Additionally, we conducted a transplant experiment recording plant survival on 2 years in order to validate the model. Lastly, to evaluate if inoculation with Antarctic endophytes has negative impacts on native soil microorganisms, we compared the biodiversity of fungi and bacterial in the rhizospheric soil of transplanted individuals of N. alessandrii inoculated and non-inoculated with fungal endophytes. We found that inoculation with root-endophytes produced significant increases in N. alessandrii and N. glauca photosynthetic rates, water use efficiencies and cumulative growth. In N. alessandrii , seedling survival was significantly greater on inoculated plants compared with non-inoculated individuals. For this species, a spatial distribution modeling revealed that, inoculation with root-fungal endophytes could potentially increase the current distributional range by almost threefold. Inoculation with root-fungal endophytes, did not reduce native rhizospheric microbiome diversity. Our results suggest that the studied consortium of Antarctic root-fungal endophytes improve the ecophysiological performance as well as the survival of inoculated trees and can be used as a biotechnological tool for the restoration of endangered tree species. [ABSTRACT FROM AUTHOR]

Accurate maps of the spatial distribution of tropical tree species provide valuable insights for ecologists and forest management. The discrimination of tree species for economic, ecological, and technical reasons is usually necessary for achieving promising results in tree species mapping. Most of the data used in tree species mapping normally have some degree of imbalance. This study aimed to assess the effects of imbalanced data in identifying and mapping trees species under threat in a selectively logged sub-montane heterogeneous tropical forest using random forest (RF) and support vector machine with radial basis function (RBF-SVM) kernel classifiers and WorldView-2 multispectral imagery. For comparison purposes, the original imbalanced dataset was standardized using three data sampling techniques: oversampling, undersampling, and combined oversampling and undersampling techniques in R. The combined oversampling and undersampling technique produced the best results: F1-scores of 68.56 ± 2.6% for RF and 64.64 ± 3.4% for SVM. The balanced dataset recorded improved classification accuracy compared to the original imbalanced dataset. This research observed that more separable classes recorded higher F1-scores. Among the species, Syzygium guineense and Zanthoxylum gilletii were the most accurately mapped whereas Newtonia buchananii was the least accurately mapped. The most important spectral bands with the ability to detect and distinguish between tree species as measured by random forest classifier, were the Red, Red Edge, Near Infrared 1, and Near Infrared 2.

Climatic variations influence the adaptive capacity of trees within tropical montane cloud forests species. Phenology studies have dominated current studies on tree species. Leaf vein morphology has been related to specific climatic oscillations and varies within species along altitudinal gradients. We tested that certain Neotropical broad leaf Magnolia species might be more vulnerable to leaf vein adaptation to moisture than others, as they would be more resilient to the hydric deficit. We assessed that leaf vein trait variations (vein density, primary vein size, vein length, and leaf base angle) among four Magnolia species (Magnolia nuevoleonensis, M. alejandrae, M. rzedowskiana, and Magnolia vovidesii) through the Mexican Tropical montane cloud forest with different elevation gradient and specific climatic factors. The temperature, precipitation, and potential evaporation differed significantly among Magnolia species. We detected that M. rzedowskiana and M. vovidesii with longer leaves at higher altitude sites are adapted to higher humidity conditions, and that M. nuevoleonensis and M. alejandrae inhabiting lower altitude sites are better adjusted to the hydric deficit. Our results advance efforts to identify the Magnolia species most vulnerable to climate change effects, which must focus priorities for conservation of this ecosystem, particularly in the Mexican tropical montane cloud forests.

Tuber species are hypogeous mycorrhizal symbionts distributed almost worldwide and associated with several tree families. In this study, we recorded the occurrence of two Tuber species (clade Puberulum) in the Acatlán Volcano (Veracruz, Eastern Mexico). They were detected by the means of the internal transcribed spacer (ITS) of nuclear ribosomal DNA sequences obtained from ectomycorrhizal samples collected at the site. The Tuber ectomycorrhizas were related symbiotically with Alnus acuminata and Fagus grandifolia var. mexicana. This is the first report of Tuber associated with these trees. The anatomical and morphological characterization of the ectomycorrhizae are presented along with illustrations. [ABSTRACT FROM AUTHOR]

Interactions between trees and ectomycorrhizal fungi are critical to the growth and survival of both partners. However, ectomycorrhizal symbiosis has barely been explored in endangered trees, and no information is available regarding soil spore banks of ectomycorrhizal fungi from forests of threatened trees. Here, we evaluated soil spore banks of ectomycorrhizal fungi from endangered Japanese Douglas-fir ( Pseudotsuga japonica) forests using bioassay approaches with congeneric P. menziesii and Pinus densiflora seedlings in combination with molecular identification techniques. Rhizopogon togasawariana was predominant in soil propagule banks and was found in all remaining P. japonica forests when assayed with P. menziesii, while no colonization of this fungus was observed on Pinus seedlings. Given the observed specificity of R. togasawariana for P. menziesii and its phylogenetic position within the Pseudotsuga-specific Rhizopogon lineage, its geographical distribution is likely restricted to the remaining Japanese Douglas-fir forests, indicating a high extinction risk for this fungus as well as its endangered host. Spore banks of R. togasawariana remained highly infective after preservation for 1 year or heat treatment at 70 °C, suggesting an ecological strategy of establishing ectomycorrhizal associations on regenerating Japanese Douglas-fir seedlings after disturbance, as observed in other Rhizopogon-Pinaceae combinations. Therefore, the regeneration of Japanese Douglas-fir seedlings may depend largely on the soil spore banks dominated by R. togasawariana, which has co-evolved with the Japanese Douglas-fir for over 30 million years. More attention must be paid to underground ectomycorrhizal fungi for the conservation of endangered tree species, especially in the era of human-induced mass extinction. [ABSTRACT FROM AUTHOR]

The determination of favorable light habitat conditions per species and life stage is transcendental, for both ex situ and in situ conservation strategies of endangered forest tree species, and for their utilization as plantation trees. This becomes especially important when planting material is scarce. We studied the multivariate responses in biomass allocation and in gas exchange to light and to CO2 in Cedrela salvadorensis seedlings, grown under similar light conditions as those this species faces in nature. During a period of 135 days, groups of ten seedlings were put under 75, 45, 15 and 3.5% of full sun exposure obtained with neutral shade cloth, under nursery conditions. A series of biomass allocation variables and detailed gas exchange parameters (photosynthesis response curves to light and to internal carbon concentration) were measured at the end of the growth period in plants of the four treatments. According to the principal component analyses, highest values of gas exchange response were associated with the lower values of biomass allocation traits. These changes can be associated with resource-conservative and resource-acquisitive strategies, where the C. salvadorensis seedlings acclimatize their traits for the exploration and exploitation of light, to high or to dim light environment, respectively. The multivariate analyses also showed that the plants had a high performance at 45% of light environments. These results suggest that 45% of light environment was the optimal light habitat of this species at the tested developing stage. Our results have important implications to choose the best natural habitat for a successful establishment of C. salvadorensis. We propose practical considerations for programs of reforestation or reintroduction where this species be involved. Rev. Biol. Trop. 64 (3): 1143-1154. Epub 2016 September 01. [ABSTRACT FROM AUTHOR]

During the last century, the eastern United States has functionally lost two major tree species (American chestnut and American elm), two more, eastern and Carolina hemlock, will likely be functionally extinct during much of their ranges by 2050. Carolina hemlock forests are geographically limited to high elevations in the southern Appalachian Mountains and are considered to be endangered. We collected forest stand, composition, and tree age data at the beginning of a hemlock woolly adelgid (HWA) infestation. Prior to the arrival of HWA, Carolina hemlocks were healthy and densely populated in the overstory and understory. While Carolina hemlock regenerated successfully and continuously from 1850 to 2010, the development of this Carolina hemlock forest will be altered by the HWA and may result in an increase in the density of northern red oak, white oak, mountain laurel, and Catawba rhododendron. Carolina hemlocks prefer cool, wet summers with older trees experiencing greater reductions in radial growth than younger trees during droughts. This study demonstrates that dendrochronological techniques can provide critical annual information on Carolina hemlock forest development and tree age-climate response. Our results provide a multicentury perspective for conservation efforts and management of Carolina hemlock forests in the southern Appalachian Mountains. [ABSTRACT FROM AUTHOR]

The present study reports a protocol for germination of Strychnos potatorum (ver. Tel. Chilla) using zygotic embryo culture as an embryo rescue method. A 100% germination rate was obtained by culturing the embryos on full-strength Murashige and Skoog's medium (MS) containing 20 g/L sucrose in comparison to McCown and Lloyd's Woody Plant Medium (WPM). Germination rates decreased when the sucrose concentration was lower or higher than 20 g·L. WPM/MS medium containing glucose at levels 30, 20, 15 g·L showed a smaller percentage of germination and at quarter strength, WPM/MS medium with glucose did not respond. Multiple shoot formation was found at 1.0-2.0 mg/L BAP; 3.0 mg/L Kn; 2.0 mg/L TDZ on MS medium with 20 g·L sucrose. Germination rates improved when the embryos were placed upright (vertically) in the medium. The in vitro germinated seedlings were acclimatized in a walk-in-chamber and maintained in the green house with the survival rate of 65%-75%. These plants were transferred to the field and were found to be phenotypically normal, healthy and similar to donor plants. This protocol will be useful to overcome seed dormancy and for rapid multiplication and conservation of S. potatorum using zygotic embryo culture. [ABSTRACT FROM AUTHOR]

The physiological and molecular processes controlling zygotic and somatic embryo development in angiosperms are mediated by a hierarchically organized program of gene expression. Despite the overwhelming information available about the molecular control of the embryogenic processes in angiosperms, little is known about these processes in gymnosperms. Here we describe the cloning and characterization of the expression pattern of the Araucaria angustifolia putative homolog of a SOMATIC EMBRYOGENESIS RECEPTOR- LIKE KINASE ( SERK) gene family member, designated as AaSERK1. The Araucaria AaSERK1 gene encodes a leucine-rich repeat receptor-like kinase showing significant similarity to angiosperm homologs of SERK1, known to be involved in early somatic and zygotic embryogenesis. Accordingly, RT-PCR results showed that AaSERK1 is preferentially expressed in Araucaria embryogenic cell cultures. Additionally, in situ hybridization results showed that AaSERK1 transcripts initially accumulate in groups of cells at the periphery of the embryogenic calli and then are restricted to the developing embryo proper. Our results indicate that AaSERK1 might have a role during somatic embryogenesis in Araucaria, suggesting a potentially conserved mechanism, involving SERK-related leucine-rich repeat receptor-like kinases, in the embryogenic processes among all seed plants. [ABSTRACT FROM AUTHOR]

Ocotea catharinensis is a basal angiosperm and an endangered tree species from the Brazilian Atlantic Rain Forest. Despite its economical and ecological importance, mass-propagation of this species is hampered by seldom-produced short-lived seeds, and in vitro propagation is challenged by frequently malformed somatic embryos. Therefore, O. catharinensis somatic embryos are also a good experimental material to study the physiological and molecular mechanisms underlying in vitro morphogenesis. In an ongoing effort to characterize genes expressed during somatic embryogenesis of O. catharinensis we have cloned two Ocotea WUSCHEL-related genes. According to our RT-PCR data, both genes were preferentially expressed in embryogenic cell aggregates. One of them, OcWUS, is a possible ortholog of the Arabidopsis WUSCHEL ( WUS) gene, which codes for a homeodomain-containing protein involved in the specification and maintenance of the shoot apical meristem. We analyzed the expression patterns of OcWUS and OcWOX4 by RT-PCR, and OcWUS expression was also assessed by in situ hybridization. The expression patterns of OcWUS were very similar to those described for the Arabidopsis WUS. OcWUS transcripts were generally restricted to a small group of cells in the center of the putative shoot apical meristem of O. catharinensis somatic embryos. Perturbed expression of OcWUS might be related to abnormally formed somatic embryos of O. catharinensis obtained through tissue culture. [ABSTRACT FROM AUTHOR]

• Background and Aims Dalbergia nigra, known as Brazilian rosewood, is an endangered tree species restricted to the Brazilian Atlantic Forest and has been intensively logged for five centuries due to its high-quality wood. The objective of the present study was to assess the genetic variation and structure in adults and saplings of the species from a large reserve of the Atlantic Forest, the Rio Doce State Park, and from two small surrounding fragments, one better preserved and another with a high degree of anthropogenic disturbance.• Methods Analyses of genetic variation and structure were conducted by studying allozyme markers. Seven putative enzymatic loci were resolved, five of them being polymorphic.• Key Results The mean numbers of alleles per locus (A) were 1·93 and 1·73, while the percentages of polymorphic loci (P) were 93 and 73 % for adults and saplings, respectively. Saplings from the fragment with high anthropogenic disturbance exhibited the lowest values of A and P. The fragment that constitutes a conservation area exhibited genetic variation similar to the population from the large reserve. The observed (Ho) and expected (He) heterozygosities were not significantly different among the three populations. Only sapling populations showed FST values (divergence among populations) significantly different from zero over all studied loci. The fragment with high anthropogenic disturbance exhibited considerable genetic divergence in relation to the above-cited populations.• Conclusions The evaluated populations displayed mean levels of genetic variation intermediate to those expected for narrow and widespread species. The results suggest that fragments with similar area and geographical distance from a large protected reserve can exhibit different levels of genetic variation, depending on the degree of anthropogenic disturbance. The considerable genetic variation in the protected fragment points to the importance of adequate conservation of small fragments for the preservation of genetic variation in D. nigra. [ABSTRACT FROM AUTHOR]

Accurate maps of the spatial distribution of tropical tree species provide valuable insights for ecologists and forest management. The discrimination of tree species for economic, ecological, and technical reasons is usually necessary for achieving promising results in tree species mapping. Most of the data used in tree species mapping normally have some degree of imbalance. This study aimed to assess the effects of imbalanced data in identifying and mapping trees species under threat in a selectively logged sub-montane heterogeneous tropical forest using random forest (RF) and support vector machine with radial basis function (RBF-SVM) kernel classifiers and WorldView-2 multispectral imagery. For comparison purposes, the original imbalanced dataset was standardized using three data sampling techniques: oversampling, undersampling, and combined oversampling and undersampling techniques in R. The combined oversampling and undersampling technique produced the best results: F1-scores of 68.56 ± 2.6% for RF and 64.64 ± 3.4% for SVM. The balanced dataset recorded improved classification accuracy compared to the original imbalanced dataset. This research observed that more separable classes recorded higher F1-scores. Among the species, Syzygium guineense and Zanthoxylum gilletii were the most accurately mapped whereas Newtonia buchananii was the least accurately mapped. The most important spectral bands with the ability to detect and distinguish between tree species as measured by random forest classifier, were the Red, Red Edge, Near Infrared 1, and Near Infrared 2. [ABSTRACT FROM AUTHOR]

Climatic variations influence the adaptive capacity of trees within tropical montane cloud forests species. Phenology studies have dominated current studies on tree species. Leaf vein morphology has been related to specific climatic oscillations and varies within species along altitudinal gradients. We tested that certain Neotropical broad leaf Magnolia species might be more vulnerable to leaf vein adaptation to moisture than others, as they would be more resilient to the hydric deficit. We assessed that leaf vein trait variations (vein density, primary vein size, vein length, and leaf base angle) among four Magnolia species (Magnolia nuevoleonensis, M. alejandrae, M. rzedowskiana, and Magnolia vovidesii) through the Mexican Tropical montane cloud forest with different elevation gradient and specific climatic factors. The temperature, precipitation, and potential evaporation differed significantly among Magnolia species. We detected that M. rzedowskiana and M. vovidesii with longer leaves at higher altitude sites are adapted to higher humidity conditions, and that M. nuevoleonensis and M. alejandrae inhabiting lower altitude sites are better adjusted to the hydric deficit. Our results advance efforts to identify the Magnolia species most vulnerable to climate change effects, which must focus priorities for conservation of this ecosystem, particularly in the Mexican tropical montane cloud forests. [ABSTRACT FROM AUTHOR]

Ex situ conservation is an important complementary strategy for in situ to conserve endangered plant species. However, the limited areas designated for ex situ conservation such as in botanic gardens have become a great challenge for conservation practitioners and scientists attempting to optimally conserve the genetic diversity of targeted plant species. Our study aimed to assess genetic diversity and structure of wild seedlings of Vatica bantamensis, an endemic and critically endangered dipterocarp from Java (Indonesia). We also estimated genetic differentiation between the wild seedlings and existing ex situ collection and evaluated the genetic diversity preserved in the ex situ collection. Our analysis, using 730 single-nucleotide polymorphisms loci, showed that wild seedlings exhibited higher genetic diversity than the ex situ collection (nucleotide diversity, µ = 0.26 and 0.16, respectively). Significant genetic differentiation was also detected (F ST = 0.32) between wild seedlings and ex situ collection. Furthermore, we found high kinship within the ex situ collection suggesting low genetic diversity since the founding collection. We also detected three distinct genetic clusters from all samples combined (analysis of molecular variance, ϕ = 0.48, p <.001), with two clusters present in the wild seedlings that were not represented in the ex situ collection. We recommend that supplementary collections from the two newly identified genetic clusters in the wild seedlings should be incorporated to increase genetic diversity in the ex situ collection. Furthermore, our study demonstrated that understanding the population genetics of targeted endangered species provides better results for ex situ conservation strategies. [ABSTRACT FROM AUTHOR]