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Radiocarbon is a radionuclide of considerable interest due to its long half-life and high environmental mobility. Since carbon is the biological backbone of the biosphere, radiocarbon can incorporate very quickly into the natural carbon cycle. Considering the importance of the radionuclide, articles on radiocarbon research belonging to various fields: age dating, soil dynamics, environmental mobility, metrology, nuclear research, and radiological impact were reviewed to provide an overview about the radiocarbon starting from its origin to management to reduce the radiological hazard. The review also highlighted less explored research areas such as: (a) impact of seasonal variation on environmental dynamics of 14C, (b) root uptake of 14C or transfer from contaminated soil to vegetation, (c) data of model parameters for radiological environmental impact assessment, (d) impact of climate change on C dynamics in the environment and (e) development of technologies for 14C management in nuclear waste, which needs to be more explored in future research. Furthermore, the review shows that environmental 14C dynamics, transport modelling, and radiological impact assessment modelling studies are less explored in non-temperate regions and need more attention in future research. [ABSTRACT FROM AUTHOR]

Root tips are the main components of absorptive fine roots, but their seasonal dynamics and relationship to environmental factors remain unclear due to the difficulties in methodology. In this study, we explored the temporal patterns of root-tip production and mortality in monoculture plantations of five temperate tree species at a common site in northeastern China, and identified the general environmental controls on such processes. We made monthly in-situ assessments of root tip length (RTL) production and mortality in two hardwood and three coniferous species with a minirhizotron (MR) method during the growing seasons of 2008 and 2009. Air temperature, rainfall, soil temperature and water content at 10 cm depth were determined concurrently. RTL production in all species exhibited consistent peaks in summer (June–August) in two growing seasons. RTL mortality showed substantial interannual and interspecific variability, with peaks in autumn and winter in 2008, but various patterns in 2009. RTL production positively correlated with monthly soil and air temperature across all species, and with monthly rainfall in three coniferous species. However, there was no significant correlation between RTL production and soil water content. By contrast, RTL mortality was weakly related to environmental factors, showing positive correlations with soil temperature in Korean spruce, and with rainfall in Korean pine and Korean spruce. Our findings suggest that the seasonal patterns of RTL production are convergent across the five temperate tree species due to the overlapped distribution of heat and rainfall, which can conduce roots to maximizing the acquisition of nutrient resources in the soil. [ABSTRACT FROM AUTHOR]

Objective: Black poplar (Populus nigra L.) is a species native to Eurasia with a wide distribution area. It is an ecologically important species from riparian ecosystems, that is used as a parent of interspecific (P. deltoides x P. nigra) cultivated poplar hybrids. Variant detection from transcriptomics sequences of 241 P. nigra individuals, sampled in natural populations from 11 river catchments (in four European countries) is described here. These data provide new valuable resources for population structure analysis, population genomics and genome-wide association studies., Data Description: We generated transcriptomics data from a mixture of young differentiating xylem and cambium tissues of 480 Populus nigra trees sampled in a common garden experiment located at Orléans (France), corresponding to 241 genotypes (2 clonal replicates per genotype, at maximum) by using RNAseq technology. We launched on the resulting sequences an in-silico pipeline that allowed us to obtain 878,957 biallelic polymorphisms without missing data. More than 99% of these positions are annotated and 98.8% are located on the 19 chromosomes of the P. trichocarpa reference genome. The raw RNAseq sequences are available at the NCBI Sequence Read Archive SPR188754 and the variant dataset at the Recherche Data Gouv repository under https://doi.org/10.15454/8DQXK5 ., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Leaves are the primary photosynthetic organs, providing essential substances for tree growth. It is important to obtain an anatomical understanding and regulatory network analysis of leaf development. Here, we studied leaf development in Populus Nanlin895 along a development gradient from the newly emerged leaf from the shoot apex to the sixth leaf (L1 to L6) using anatomical observations and RNA-seq analysis. It indicated that mesophyll cells possess obvious vascular, palisade, and spongy tissue with distinct intercellular spaces after L3. Additionally, vacuoles fuse while epidermal cells expand to form pavement cells. RNA-seq analysis indicated that genes highly expressed in L1 and L2 were related to cell division and differentiation, while those highly expressed in L3 were enriched in photosynthesis. Therefore, we selected L1 and L3 to integrate ATAC-seq and RNA-seq and identified 735 differentially expressed genes (DEGs) with changes in chromatin accessibility regions within their promoters, of which 87 were transcription factors (TFs), such as ABI3VP1, AP-EREBP, MYB, NAC, and GRF. Motif enrichment analysis revealed potential regulatory functions for the DEGs through upstream TFs including TCP, bZIP, HD-ZIP, Dof, BBR-BPC, and MYB. Overall, our research provides a potential molecular foundation for regulatory network exploration in leaf development during photosynthesis establishment., (© 2023. The Author(s), under exclusive licence to Springer Nature B.V.)

The stability-related asymmetry in roots, trunk, and crown is always found as a typical effect of biomechanical design under heterogeneous stimulus environment. However, it appears to be a conflict between the biomechanical principle and the source-sink distance of nutrient allocation strategies when the orientational asymmetry occurs. Adaptive growth strategies associated with biomass and nutrient allocation remain to be explored. This study used both the minirhizotron and harvest methods to test the effect of trunk inclination of camphor trees (Cinnamomum camphora) and found that the asymmetry coefficient of root biomass was − 0.29, showing more root biomass distributed on the other side of trunk inclination. This side had larger surface area and volume of fine roots, the smaller in diameter and the larger in length of the first level roots, higher leaf total nitrogen (TN) and slightly higher root TN content, higher activities of antioxidant enzymes SOD, POD, and CAT in leaves, and lower soluble sugar and protein. The biomass, morphological and physiological characteristics suggest that trees may follow both the biomechanical design and source-sink distance of nutrient allocation strategies. The research results expand the connotation of root-shoot balance in the orientational allocation of biomass and physiological responses. [ABSTRACT FROM AUTHOR]

Aims: Soil fauna play a key role in the litter decomposition process in two ways; directly via fragmentation and consumption of the litter, and indirectly through changes in soil structure and the activity of microorganisms. The study aimed at better understanding how soil fauna affects the release of nutrients from litter. Methods: We conducted a litter decomposition experiment using litterbags of three mesh sizes (0.01 mm, 1 mm, and 4 mm), and chemical treatments (no naphthalene; naphthalene application) to assess soil fauna effect on nutrient release in a poplar plantation in eastern China over a two-year period from Jan 2019 to Dec 2020. Results: We found that the contribution of soil fauna to the mass loss of poplar leaf litter was 29% over the two-year period, and the contribution was more pronounced within the first four months. Soil macrofauna and meso-/micro- fauna contributed similarly to leaf litter mass loss, while microbial decomposition contributed the most to the decomposition process. The presence of soil fauna significantly promoted the degradation of cellulose and lignin, and accelerated the release of nitrogen at later stages of decomposition. A structural equation model revealed that higher soil fauna abundance not only promoted the litter decay rate directly, but also indirectly through modifying nitrogen and lignin contents. Conclusions: Our results highlight the importance of soil fauna on cellulose and lignin degradation, and the importance of including this when simulating decomposition models for obtaining a better mechanistic understanding of forest litter decomposition. [ABSTRACT FROM AUTHOR]

Cross laminated timber (CLT) and glue laminated timber (glulam or GLT) are gaining attention given their use in high-rise buildings as climate mitigation concept. In most cases softwood is used to manufacture these engineered wood products, yet fast-growing and widespread hardwood species such as hybrid poplar have potential to meet the increasing demand. In addition to the mechanical performance, it is also key to investigate the fungal susceptibility and moisture dynamics of poplar, to gain insight into the service life of engineered poplar products. This paper therefore investigates the fungal decay resistance, as well as the moisture sorption properties of (thermally modified) hybrid poplar clones and Norway spruce. Fungal decay resistance was tested using the mini-block test. Moisture dynamics were evaluated using a floating test and dynamic vapor sorption (DVS). A higher fungal decay resistance and a significant decrease of moisture sorption was observed for thermally modified poplar. Our results show that the overall moisture properties of poplar and spruce are similar and that differences among the poplar clones are negligible, demonstrating the potential of poplar wood for engineered wood products. Together with findings on the mechanical properties in the literature, these results on durability and moisture performance give extra support for the potential utilization of poplar CLT in constructions. [ABSTRACT FROM AUTHOR]

Background: Afforestation of non-forestland is a new measure by the European Union to enhance climate mitigation and biodiversity. Hybrid aspen (Populus tremula L. × P. tremuloides Michx.) is among the suitable tree species for afforestation to produce woody biomass. However, the best performing genotypic material for intensive biomass production and its physiological adaptation capacity is still unclear. We compared 22 hybrid aspen genotypes growth and leaf physiological characteristics (stomatal conductance, net photosynthesis, intrinsic water-use efficiency) according to their geographical north- or southward transfer (European P. tremula parent from 51° to 60° N and North American P. tremuloides parent from 45° to 54° N) to hemiboreal Estonia (58° N) in a completely randomized design progeny trial. We tested whether the growth ranking of genotypes of different geographical origin has changed from young (3-year-old) to mid-rotation age (13-year-old). The gas exchange parameters were measured in excised shoots in 2021 summer, which was characterised with warmer (+ 4 °C) and drier (17% precipitation from normal) June and July than the long-term average. Results: We found that the northward transfer of hybrid aspen genotypes resulted in a significant gain in growth (two-fold greater diameter at breast height) in comparison with the southward transfer. The early selection of genotypes was generally in good accordance with the middle-aged genotype ranking, while some of the northward transferred genotypes showed improved growth at the middle-age period in comparison with their ranking during the early phase. The genotypes of southward transfer demonstrated higher stomatal conductance, which resulted in higher net photosynthesis, and lower intrinsic water-use efficiency (iWUE) compared with northward transfer genotypes. However, higher photosynthesis did not translate into higher growth rate. The higher physiological activity of southern transferred genotypes was likely related to a better water supply of smaller and consequently more shaded trees under drought. Leaf nitrogen concentration did not have any significant relation with tree growth. Conclusions: We conclude that the final selection of hybrid aspen genotypes for commercial use should be done in 10–15 years after planting. Physiological traits acquired during periods of droughty conditions may not fully capture the growth potential. Nonetheless, we advocate for a broader integration of physiological measurements alongside traditional traits (such as height and diameter) in genotype field testing to facilitate the selection of climate-adapted planting material for resilient forests. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tree bark is an important natural polymer for sound absorption. The main components in the bark of different tree species are polymers with high molecular weight such as cellulose, hemicellulose, and lignin. The aim of this study is to determine the noise reduction coefficient (NRC), lignin, alcohol-benzene solubility (ABS), carbon (C), and nitrogen (N) contents in samples taken from the bark of different tree species-black locust (Robinia pseudoacacia), narrow-leaved ash (Fraxinus angustifolia), stone pine (Pinus pinea), silver lime (Tilia tomentosa), sweet chestnut (Castanea sativa), sessile oak (Quercus petraea), and maritime pine (Pinus pinaster) and to investigate the relationship between these chemical properties and sound absorption measurements. Tree species showed a statistically significant difference in terms of all measured variables. In the correlation matrix obtained as a result of the analysis, only ABS showed a significant and the highest positive correlation with the NRC, with a correlation coefficient of r = 0.812. ABS in bark is seen as the most important chemical factor regarding sound retention, indicating the abundance of extractives in barks of different tree species. An investigation into the relationship between sound retention and different extractive substance and contents of different extractive substances in bark is recommended for further studies., Competing Interests: Declarations. Competing interests: The authors declare that they have no competing interests., (© 2025. Akadémiai Kiadó Zrt.)

Toxic contaminants from intense industrial operations are entering wetlands, harming human health and biodiversity. Macrophytes serve as principal producers in aquatic environments including natural wetlands, providing shelter, food, and, most crucially, intricate relationships with the surrounding microbial assemblage for support and microorganisms attachment. Wetlands have been nature's kidneys, for filtering water. Recent research has examined macrophytes' phytoremediation abilities. With recent improvements focused on engineered wetland technology, microbiological characterization, and genetic engineering, phytoremediation strategies have also benefited. However, little research has examined the role surrounding microbial population play on macrophyte efficiency in pollutant degradation, the extent and even mechanisms of these interactions, and their potential utility in wastewater treatment of diverse industrial effluents. Our bid for greener solutions implies that macrophyte-microorganisms' interspecific interactions for in situ treatment of effluents should be optimised to remove contaminants before discharge in natural waterbodies or for recycle water usage. This review provides for the varied types of plants and microbial interspecific interactions beneficial to effective phytoremediation processes in artificial wetland design as well as considerations and modifications in constructed wetland designs necessary to improve the bioremediation processes. Additionally, the review discusses the latest advancements in genetic engineering techniques that can enhance the effectiveness of phyto-assisted wastewater treatment. We will also explore the potential utilisation of invasive species for their demonstrated ability to remove pollutants in the controlled setting of constructed wetlands. [ABSTRACT FROM AUTHOR]

Higher productivities for loblolly pine (Pinus taeda L.) growing at exotic locations (e.g., Hawaii, Brazil) indicate that the full growth potential of this southern pine species has yet to be reached in plantations across the southeastern United States (US). The higher productivity of Hawaii-grown loblolly pine has been attributed to more favorable climate conditions. To date, physical, anatomical, and chemical property data for loblolly pine wood from exotic locations are scarce. Mid-infrared spectroscopy coupled with multivariate analysis was used to screen for chemical differences between wood samples from Hawaii (HI), North Carolina (NC), and Mississippi (MS). The principal component analysis scores plot showed that the MS samples formed a distinct cluster apart from overlapping clusters for the other two sites. Using standard wet chemistry procedures, we found that the mean lignin content for the MS site (30.1%) was significantly lower than that determined for the NC (34.5%) and HI (33.9%) sites; said lower lignin value was offset by significantly higher glucose and mannose contents. Results on the US mainland were seemingly consistent with the greater formation of latewood at sites with longer growing seasons, and the lower lignin content of latewood relative to earlywood shown for pines. Given the low percent latewood for the HI site (37.2%) relative to both mainland sites (MS, 54.8%; NC, 53.1%), yet similar lignin contents between the NC and HI sites, it appears that the relative lignin value for these exotically-grown loblolly pine trees cannot be solely attributed to the proportion of latewood. [ABSTRACT FROM AUTHOR]

Quercus pubescens Willd. is a deciduous species that can retain leaves in the winter either as dead, standing leaves (marcescence), or as living, winter-green leaves. The retention of green leaves through winter is rare in continental areas. Winter-green leaves were observed on one-year-old seedlings of Q. pubescens in the winter of 2020 in the nursery of the Faculty of Forestry that lasted until the end of April 2021. The photosynthetic activity of photosystem II was measured using the rapid light curve method based on modulated pulse chlorophyll fluorescence. We assessed the potential photosynthetic activity of the leaves across the range of physiological stages: winter-green leaves retained from the previous growing season and on the leaves from the first, second, and third growth flush during the growing season. Photosystem II of winter-green leaves attained ~50-60% of the maximal photosynthetic activity obtained in spring and summer leaves, respectively. Climate data indicated that winter-green leaves exhibited frost resistance in the winter of 2020/2021, as their photosynthetic activity was preserved despite 33 days with sub-zero temperatures. The rapid light curve method also revealed the gradual acclimation of seedlings on a flush level, with leaves from the third flush best able to use available light under high temperatures and insolation efficiently. The results of rapid light use as an indicator of seedling acclimation are discussed. Some remarks on the possible practical significance of the winter-green leaves phenomenon (as in genetic selection) are highlighted. [ABSTRACT FROM AUTHOR]

Copyright of Jurnal Fitopatologi Indonesia is the property of IPB University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The seedlings of some tree species can successfully develop in areas polluted by heavy metals. Research on such species is important in order to explore the possibility of introducing tree species for the permanent biological stabilization and reclamation of post-flotation tailings, especially after the final recycling of trace metals, but where concentrations remain much higher than in natural soils. To better understand the adaptation and reaction of Betula pendula Roth., Pinus sylvestris L., and Larix decidua Mill. seedlings to heavy metals pollution caused by tailings waste highly contaminated by trace elements: 1) the relationships between the concentration of heavy metals in the soil substrate, the efficiency of heavy metal ions accumulation in plant organs, and the biometric parameters of the seedlings; and 2) the threshold content of heavy metals in the roots above which the plant physiological response is triggered was determined. We assume that there are certain limit concentrations of heavy metals in the soil and fine roots, which depend on the tree species and beyond which the plant responds strongly to stressThe obtained results showed that Betula is a suitable species for the phytostabilization of post-flotation tailings due to its rapid growth rate and production of root biomass. The accumulation of metals in Betula roots was found to be much greater than in Pinus and Larix. Despite the high concentrations of heavy metals in the prepared substrates, there was only a slight transfer of these elements to the aboveground parts of the plant. At high soil concentrations, the heavy metals adversely affected the cellular and physiological processes of plants. In plants growing in such conditions, the activity of the antioxidant system depended both on the species and organ of the plant, as well as on the type and metal concentration. [ABSTRACT FROM AUTHOR]

Carbohydrate and nitrogen storage in seedlings can improve field growth and survival. However, carbohydrate and nitrogen reserves may compete. For instance, carbohydrate reserves can be accumulated due to sink limitation on growth triggered by nutrient deficiency. Few studies have addressed the effects of nutrient supply on carbohydrate and nutrient storage and subsequent field performance of Quercus and Pinus species with different shoot growth strategies at the early growing stage. We exposed seedlings of Pinus tabuliformis Carr and Quercus mongolica Fisch to three exponential fertilizer treatments (10, 50, 100 mg N) in the nursery for 18 weeks to assess the combined response of growth and storage of carbohydrate and nitrogen in seedlings during their first year of growth in the nursery, as well as their subsequent field performance over the next 2 years. At the end of nursery stage, high nutrient supply increased nitrogen storage in both species, increased carbohydrate concentration in Q. mongolica but decreased that in P. tabuliformis seedlings. P. tabuliformis showed higher winter mortality than Q. mongolica but field mortality of P. tabuliformis decreased with an increase in fertilizer dosage. Our findings suggest that P. tabuliformis seedlings exposed to 100 mg N per plant can mitigate the field winter mortality although it could be still under deficiency status. Given lower winter mortality in Q. mongolica seedlings, being exposed to at least 100 mg N per plant in the nursery can produce nutrient-loaded seedlings, and therefore can be considered for restoration programs in areas affected by low winter temperature. [ABSTRACT FROM AUTHOR]

The white poplar (Populus alba L.), which is tolerant to abiotic and biotic stresses, is a tree species that is resilient against changing climatic and environmental conditions, which makes it a suitable candidate for afforestation efforts. However, due to prolonged human intervention associated with the increasing population, the genetic resources of this species are at risk of loss. Additionally, while this species generally reproduces sexually, reproduction clonally via its root suckers has become widespread in some areas. Hence, the aim of this study was to investigate the genetic diversity of white poplar, which is increasingly experiencing genetic diversity loss. Herein, 15 different populations distributed overall in Türkiye were sampled, and the genetic structure and diversity of the species were examined using 10 simple sequence repeat molecular markers. The analyses revealed relatively high levels of genetic variation in the populations (observed heterozygosity: 0.50, expected heterozygosity: 0.46) and the molecular variance analysis determined 84% genetic variation within the populations. Overall, the distance between the populations decreased, the gene flow (Nm) increased, and the genetic differentiation decreased (Nm: 0.16–30.24, gene differentiation coefficient: 0.01–0.61). The principal component and phylogenetic analyses data also supported these results. The 3 populations at the highest altitude, Erzurum-Oltu, Kayseri-Akköy, and Konya-Meram, had a different genetic structure than the others. Furthermore, clonal reproduction was intensive in some populations together with the inclusion of human activities, and therefore, the genetic diversity of the species decreased. However, the white poplar populations in riverside and floodplain forests had higher genetic diversity and private alleles. For this reason, the Eskişehir-Porsuk Çayi and Samsun-Bafra populations could be recommended for in situ conservation of white poplar. This study provides information on the genetic diversity of white poplar populations in Türkiye, and thus contributes to more efficient and rational planning of breeding and conservation programs for the species. [ABSTRACT FROM AUTHOR]

Key message: When growing under similar conditions, Salix humboldtiana plants exhibit intra- and inter-clone variations in growth and branching traits, despite sharing an acrotonic branching pattern. Willows represent some of the most extended tree crop species worldwide. Understanding their global architecture could help improving the forestry based on these species and thus the associated economic activities. Our goal was to compare growth and branching traits among clones of Salix humboldtiana, the only willow native to South America. We registered the length, diameter, number of branches, branching range and the number of growth units of the vertical shoot formed by plants derived from nine clones of three Patagonian provenances of S. humboldtiana. Budbreak patterns at each node of that shoot were also analyzed. Length and number of branches were the most variable among clones, while diameter and branching range were the least variable shoot traits. The clones with the highest proportion of unbranched individuals tended to have the lowest proportion of shoots with two growth units. The probability of budbreak decreased as the distance between a bud and the shoot apex increased (acrotonic branching pattern). Our study shows that the length and the number of branches of the main axis growth unit would be key traits for clone selection, as they seem to have a high degree of endogenous determination. These traits are important aspects of the whole plant's architecture that can be used for designing, for example, agroforestry systems when it comes to clone or even species combination. [ABSTRACT FROM AUTHOR]

Phytoremediation is an environmentally friendly alternative to traditional remediation technologies, notably for soil restoration and agricultural sustainability. This strategy makes use of marginal areas, incorporates biofortification processes, and expands crop alternatives. The ecological and economic benefits of phytoremediation are highlighted in this review. Native plant species provide cost-effective advantages and lower risks, while using invasive species to purify pollutants might be a potential solution to the dilemma of not removing them from the new habitat. Thus, strict management measures should be used to prevent the overgrowth of invasive species. The superior advantages of phytoremediation, including psychological and social improvements, make it a powerful tool for both successful cleanup and community well-being. Its ability to generate renewable biomass and adapt to a variety of uses strengthens its position in developing the bio-based economy. However, phytoremediation faces severe difficulties such as complex site circumstances and stakeholder doubts. Overcoming these challenges necessitates a comprehensive approach that balances economic viability, environmental protection, and community welfare. Incorporating regulatory standards such as ASTM and ISO demonstrates a commitment to long-term environmental sustainability, while also providing advice for unique nation-specific requirements. Finally, phytoremediation may contribute to a pleasant coexistence of human activity and the environment by navigating hurdles and embracing innovation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Leucoptera sinuella (Reutti) (Lepidoptera: Lyonetiidae) is a leaf miner specialist on Salicaceae recently introduced to Chile and Argentina, where it is causing economic damage to poplar plantations. We report a field survey in a poplar nursery naturally infested showing that regardless of the poplar hybrid taxon, high variability in resistance was observed among clones within families for oviposition and leaf-mining damage. A group of susceptible and resistant hybrid poplar clones was then selected for a laboratory evaluation of oviposition (antixenosis) and leaf-mining damage (antibiosis) on potted, rooted shoot cuttings. The concentration of condensed tannins (CTs) and salicinoid phenolic glucosides (SPGs) of the leaves of the selected clones from the laboratory study was also measured. Total oviposited eggs were positively correlated with leaf area, with the lowest oviposition on TMxT 11372 clone. The lowest percentage of mined leaf area was obtained for clones TMxT 11372, TMxT 11463, and TDxD 17574, but surprisingly no correlation between the percentage of mined leaf area and concentration of CTs and SPGs was found. Resistant poplar hybrids of our study could be suitable for breeding programs aimed for L. sinuella integrated pest management. [ABSTRACT FROM AUTHOR]

DNA cytosine methylation is an epigenetic mechanism involved in regulation of plant responses to biotic and abiotic stress and its ability to change can vary with the sequence context in which a cytosine appears (CpG, CHG, CHH, where H = Adenine, Thymine, Cytosine). Quantification of DNA methylation in model plant species is frequently addressed by Whole Genome Bisulfite Sequencing (WGBS), which requires a good-quality reference genome. Reduced Representation Bisulfite Sequencing (RRBS) is a cost-effective potential alternative for ecological research with limited genomic resources and large experimental designs. In this study, we provide for the first time a comprehensive comparison between the outputs of RRBS and WGBS to characterize DNA methylation changes in response to a given environmental factor. In particular, we used epiGBS (recently optimized RRBS) and WGBS to assess global and sequence-specific differential methylation after insect and artificial herbivory in clones of Populus nigra cv. 'italica'. We found that, after any of the two herbivory treatments, global methylation percentage increased in CHH, and the shift was detected as statistically significant only by epiGBS. As regards to loci-specific differential methylation induced by herbivory (cytosines in epiGBS and regions in WGBS), both techniques indicated the specificity of the response elicited by insect and artificial herbivory, together with higher frequency of hypo-methylation in CpG and hyper-methylation in CHH. Methylation changes were mainly found in gene bodies and intergenic regions when present at CpG and CHG and in transposable elements and intergenic regions at CHH context. Thus, epiGBS succeeded to characterize global, genome-wide methylation changes in response to herbivory in the Lombardy poplar. Our results support that epiGBS could be particularly useful in large experimental designs aimed to explore epigenetic changes of non-model plant species in response to multiple environmental factors. [ABSTRACT FROM AUTHOR]

Competition between planted seedlings and vegetation is a critical constraint affecting the survival and growth of seedlings at the initial stages of forestation. Quantitatively assessing the impact of competitive vegetation on the growth of planted seedling is vital for reduction of weeding cost. This study compared the survival and growth of potentially fast-growing hybrid larch F1 seedling (Larix gmelinii var. japonica × L. kaempferi) with Japanese larch (L. kaempferi) at three competitive levels, which were 0–50%, 50–75% and 75–100% of the seedling surface covered by vegetation after planting. When more than three-quarters of the seedling surface was covered by vegetation, the survival rate of Japanese larch dropped substantially. In contrast, hybrid larch F1 sustained a high survival of 95% despite the high covering. Annual height growth significantly decreased with increasing coverage for both species. In addition, the height growth of hybrid larch F1 was significantly higher than that of Japanese larch, whereas the difference became insignificant when more than three-quarters of the surface was covered. If the requirement for weeding is whether three-quarters of the seedling surface is covered or not with vegetation, it was determined that hybrid larch F1 did not require weeding if the seedling height attained about 170 cm in the previous fall; whereas Japanese larch needed about 200 cm. The findings imply that weeding is needed to unlock the hybrid larch F1's high growth potential, and that weeding can be accomplished more than a year earlier than with Japanese larch. [ABSTRACT FROM AUTHOR]

Tropospheric ozone (O3) is a secondary pollutant that causes oxidative stress in plants due to the generation of excess reactive oxygen species (ROS). Phenylpropanoid metabolism is induced as a usual response to stress in plants, and induction of key enzyme activities and accumulation of secondary metabolites occur, upon O3 exposure to provide resistance or tolerance. The phenylpropanoid, isoprenoid, and alkaloid pathways are the major secondary metabolic pathways from which plant defense metabolites emerge. Chronic exposure to O3 significantly accelerates the direction of carbon flows toward secondary metabolic pathways, resulting in a resource shift in favor of the synthesis of secondary products. Furthermore, since different cellular compartments have different levels of ROS sensitivity and metabolite sets, intracellular compartmentation of secondary antioxidative metabolites may play a role in O3-induced ROS detoxification. Plants' responses to resource partitioning often result in a trade-off between growth and defense under O3 stress. These metabolic adjustments help the plants to cope with the stress as well as for achieving new homeostasis. In this review, we discuss secondary metabolic pathways in response to O3 in plant species including crops, trees, and medicinal plants; and how the presence of this stressor affects their role as ROS scavengers and structural defense. Furthermore, we discussed how O3 affects key physiological traits in plants, foliar chemistry, and volatile emission, which affects plant–plant competition (allelopathy), and plant–insect interactions, along with an emphasis on soil dynamics, which affect the composition of soil communities via changing root exudation, litter decomposition, and other related processes. [ABSTRACT FROM AUTHOR]

The study was conducted to estimate the genetic variability and stability in the performance of different Salix clones for important morpho-physiological traits contributing towards biomass production. After initial screening under nursery conditions, twenty-eight Salix clones were selected and planted in the field conditions of Punjab, India using Randomized Complete Block Design in 2019. On the basis of mean performance, clones PN-731, UHFS-119, UHFS-85, UHFS-101, NZ-1140, UHFS-340 and UHFS-141 were found outstanding for morphological and physiological traits and were superior to the check clone (Kashmir willow) and had witnessed maximum growth increment. Clones UHFS-85 and UHF-101 revealed stability in the growth performance during early two years of field testing along with highest index score (24 and 21, respectively), therefore, can be recommended for higher biomass production. However, clones UHFS-119, PN-731, NZ-1140, UHFS-340 and UHFS-141 with high index score and increasing pattern in growth may be evaluated further for stability and concerned end use. High heritability and genetic gain were observed for plant height, leaf area, volume index, number of branches, number of leaves, carotenoid content and number of stomata, which suggests that the clonal selection would be most effective for these traits. Highly significant genotypic and phenotypic correlation was evident for plant height with basal diameter, volume index with plant height and basal diameter and total chlorophyll with chlorophyll a and carotenoid content; may be taken into consideration while doing indirect selection for the associated character. Similarly, the genetic divergence analysis revealed that the clones present in cluster I, II and III are highly diverse and may be involved in future breeding programmes. [ABSTRACT FROM AUTHOR]

Summary: A recurring motif of Carlquist's work is the identification of traits typical for primary xylem of angiosperms as a whole, but found in the secondary xylem of certain species. These traits together make up the 'Carlquistian syndrome'. Convergent occurrence of the syndrome in plants with similar habits suggests its adaptive value. One of its components — raylessness — has received the most attention and has been regarded as the result of selection favouring stem rigidity. However, how raylessness (or the Carlquistian syndrome in general) arises ontogenetically has been little studied. Here, we report that in some plants secondary xylem resembles primary xylem of the same individual, and not that of angiosperms in general as observed by Carlquist. Based on literature and microslide surveys, we identified this prolongation of primary xylem patterns into secondary xylem in most major clades of non-monocot angiosperms, including magnoliids, asterids and rosids. [ABSTRACT FROM AUTHOR]

Vegetative and reproductive phase change and phenology are economically and ecologically important traits. Trees typically require several years of growth before flowering and, once mature, seasonal control of the transition to flowering and flower development is necessary to maintain vegetative meristems and for reproductive success. Members of two related gene subfamilies, FLOWERING LOCUST (FT) and TERMINAL FLOWER1 (TFL1)/ CENTRORADIALIS (CEN)/ BROTHER OF FT AND TFL1 (BFT), have antagonistic roles in flowering in diverse species and roles in vegetative phenology in trees, but many details of their functions in trees have yet to be resolved. Here, we used CRISPR/Cas9 to generate single and double mutants involving the five Populus FT and TFL1/CEN/BFT genes. The ft1 mutants exhibited wild-type-like phenotypes in long days and short days, but after chilling, to release dormancy, they showed delayed bud flush and GA3 could compensate for the ft1 mutation. After rooting and generating some phytomers in tissue culture, both cen1 and cen1ft1 mutants produced terminal as well as axillary flowers, indicating that the cen1 flowering phenotype is independent of FT1. The CEN1 showed distinct circannual expression patterns in vegetative and reproductive tissues and comparison with the expression patterns of FT1 and FT2 suggests that the relative levels of CEN1 compared with FT1 and FT2 regulate multiple phases of vegetative and reproductive seasonal development. [ABSTRACT FROM AUTHOR]

Melampsora medusae f. sp. deltoidae is causing serious foliar rust disease on Populus deltoides clones in India. In the present study, a novel fungal hyperparasite on M. medusae has been reported. The hyperparasitic fungus was isolated from the uredeniospores of the rust fungi and identified as Cladosporium oxysporum by morphological characterization and DNA barcode technique based on the Internal Transcribed Spacer (ITS) region of nrDNA and beta-tubulin (TUB) gene region. Hyperparasitism was further confirmed through leaf assay and cavity slide methods. Leaf assay method showed no adverse effect of C. oxysporum on poplar leaves. However, the mean germination percentage of urediniospores was significantly decreased (p < 0.05) in the cavity slide method when a conidial suspension (1.5 × 107 conidia per ml) of C. oxysporum was applied in different deposition sequences. Scanning and light microscopic observations were made to explore the mode of action of the hyperparasitism. The antagonistic fungus vividly showed three different types of antagonism mechanisms, including enzymatic, direct, and contact parasitism. Alternatively, by screening 25 high-yielding clones of P. deltoides, five clones (FRI-FS-83, FRI-FS-92, FRI-FS-140, FRI-AM-111, and D-121) were enlisted under highly resistant category. Present study revealed an antagonistic relationship between C. oxysporum and M. medusae, which could be an effective method of biocontrol in field plantations of poplar. Combining this biocontrol approach with the use of resistant host germplasm could be an environment friendly strategy for preventing foliar rust and increasing poplar productivity in northern India. [ABSTRACT FROM AUTHOR]

2,4-Dinitrophenol (2,4-DNP) is recognized as an emerging contaminant due to its high toxicity and poor biodegradability, posing a threat to animals, plants, and human health. The efficient removal of 2,4-DNP remains a challenging issue in phytoremediation research, particularly because of its toxic effects on plants. To address this, a hydroponic simulation experiment was conducted to investigate the impact of adding exogenous methyl jasmonate (MeJA) on the tolerance and purification capabilities of Salix matsudana Koidz (S. matsudana) seedlings exposed to 2,4-DNP. The results indicated that the addition of exogenous MeJA mitigated the damage caused by 2,4-DNP to S. matsudana seedlings by enhancing the activity of antioxidant enzymes, reducing excess reactive oxygen species (ROS), lowering membrane lipid peroxidation, and minimizing membrane damage. Notably, the most effective alleviation was observed with the addition of 50 mg·L -1 MeJA. Furthermore, exogenous MeJA helped maintain the biomass indices of S. matsudana seedlings under 2,4-DNP stress and increased the removal efficiency of 2,4-DNP by these seedlings. Specifically, the addition of 50 mg·L -1 MeJA resulted in a removal percentage of 79.57%, which was 11.88% higher than that achieved with 2,4-DNP treatment. In conclusion, exogenous MeJA can improve the plant resistance and enhance 2,4-DNP phytoremediation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Many studies have highlighted the value of mixed plantations and their advantages over monocultures. The success of mixed plantations is usually assessed by measuring the increase in biomass and/or plant production compared to the corresponding monocultures. Among the structural determinants of growth, the vertical distribution of branches and crown shape are important to take into account because they directly impact access to light, which conditions tree growth. We evaluated the effect of two types of species mixtures in northeastern France (agroforestry and a forest mixture) on the crown architecture of poplars (Populus deltoides × P. nigra) and alder (Alnus glutinosa) after seven growing seasons and compared the mixtures to their respective monocultures. Four tree architecture variables (height, crown depth, crown projection area, crown volume) were evaluated. Our study shows that the poplars in the agroforestry plot altered their crown morphology through a true mixture effect due to the presence of clover, an N2-fixing species, as well as to reduced competition for light due to larger spacing compared to the monoculture. In the forest mixture, despite a stratification of the canopy suggesting an optimized sharing of the aerial niche, thus possibly creating an additive effect, poplar crown morphology was not different compared to the monoculture. Finally, the different types of mixtures did not affect alder crown morphology. From an agronomic perspective, the more important crown development that occurred when the poplar was associated with an N2-fixing crop makes this type of mixture a very promising way to increase the contribution of biomass to the renewable energy mix in Europe. [ABSTRACT FROM AUTHOR]

Poplars establish on alluvial bars within sand and gravel-bed rivers. Alluvial bars also provide particularly suitable habitats for the proliferation of ants. We hypothesized that ants, by modifying substrate structure and resource availability in fluvial habitats, positively influence poplar growth during its establishment stage. We conducted a preliminary nine-month ex situ greenhouse experiment with one ant species (Lasius niger L.) and six different genotypes of poplar cuttings (Populus nigra L.), both collected on the Garonne River, SW France. Three main treatments: 'P. nigra alone', 'P. nigra without ants and with ant food' and 'P. nigra with ants and ant food' were applied. After one growing season, we tested differences in branching length and biomass of stems, roots and leaves. Certain genotypes showed significant differences in growth, but there were no significant differences in stem length, dry mass of stems and roots between the three treatments. The total biomass of poplars after the first growing season was positively affected by the initial size of the cuttings and was modulated by the genotype independently from the treatments. However, an increased poplar growth for the treatment without ants and with ant food was observed according to significant differences in dry weight of leaves and total biomass (i.e. dry mass of stems, roots and leaves) for the pooled genotypes across treatments. We discuss our results with the aim of serving as a reference for future in situ and ex situ experiments and field measurements exploring interactions between ants and poplars, specifically in riparian ecosystems. [ABSTRACT FROM AUTHOR]

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Background: Necrotizing pathogens pose an immense economic and ecological threat to trees and forests, but the molecular analysis of these pathogens is still in its infancy because of lacking model systems. To close this gap, we developed a reliable bioassay for the widespread necrotic pathogen Botrytis cinerea on poplars (Populus sp.), which are established model organisms to study tree molecular biology. Results: Botrytis cinerea was isolated from Populus x canescens leaves. We developed an infection system using fungal agar plugs, which are easy to handle. The method does not require costly machinery and results in very high infection success and significant fungal proliferation within four days. We successfully tested the fungal plug infection on 18 poplar species from five different sections. Emerging necroses were phenotypically and anatomically examined in Populus x canescens leaves. We adapted methods for image analyses of necrotic areas. We calibrated B. cinerea DNA against Ct-values obtained by quantitative real-time polymerase chain reaction and measured the amounts of fungal DNA in infected leaves. Increases in necrotic area and fungal DNA were strictly correlated within the first four days after inoculation. Methyl jasmonate pretreatment of poplar leaves decreased the spreading of the infection. Conclusions: We provide a simple and rapid protocol to study the effects of a necrotizing pathogen on poplar leaves. The bioassay and fungal DNA quantification for Botrytis cinerea set the stage for in-depth molecular studies of immunity and resistance to a generalist necrotic pathogen in trees. [ABSTRACT FROM AUTHOR]

Tree wind break systems are found in many parts of the world. In particular in windy and arid regions they help to increase crop yields and reduce crop water consumption. Due to these reasons, tree wind breaks have a long tradition in Central Asia and were strongly propagated there during Soviet Union times. After the Soviet Union had disintegrated and the countries in Central Asia had become independent, energy supplies from Russia ceased and fuel wood became the primary energy source for large parts of the population, in particular rural population. Consequently, most of those tree wind breaks were cut down for fuel wood during the 1990s. Now, governments wish to restore these systems, but many farmers are skeptical about the economic returns from investment in tree wind breaks. Against this background, this study calculated revenues, costs, and profits for tree wind break systems of poplars combined with wheat, barley, corn, alfalfa, cotton, and rice in Kyrgyzstan, based on interviews and field observations. Tree wind breaks with more than one row of trees (multiple row type) did not result in financial gains for most crop tree wind break systems compared to open field conditions, while single tree wind breaks were cost-neutral or resulted in small economic gains, also under different discount rates and revenues attained from crops and trees. Among the different grid sizes, the 200 m × 200 m grid attained the highest financial surplus compared with open field conditions and other grid sizes. Thereby, effectively it is recommended to establish tree wind breaks along existing field borders or irrigation ditches while keeping an average distance between tree lines of 200 m, in order not to impede farm operations. [ABSTRACT FROM AUTHOR]

A 150-day experiment was performed to investigate the stimulatory effect of a promising phytoremediation strategy consisting of Suaeda heteroptera (S. heteroptera), Nereis succinea (N. succinea), and oil-degrading bacteria for cleaning up total petroleum hydrocarbons (TPHs) in spiked sediment. Inoculation with oil-degrading bacteria and/or N. succinea increased plant yield and TPH accumulation in S. heteroptera plants. The highest TPH dissipation (40.5%) was obtained in the combination treatment, i.e., S. heteroptera + oil-degrading bacteria + N. succinea, in which the sediment TPH concentration decreased from an initial value of 3955 to 2355 mg/kg in 150 days. BAF, BCF, and TF confirmed the role of N. succinea and oil-degrading bacteria in the amelioration and translocation of TPHs. In addition, TPH toxicity of S. heteroptera was alleviated by N. succinea and oil-degrading bacteria addition through the reduction of oxidative stress. Therefore, S. heteroptera could be used for cleaning up oil-contaminated sediment, particularly in the presence of oil-degrading bacteria + N. succinea. Field studies on oil-degrading bacteria + N. succinea may provide new insights on the rehabilitation and restoration of sediments contaminated by TPHs. Our study attempted to investigate the stimulatory effect of a promising phytoremediation strategy consisting of Suaeda heteroptera (S. heteroptera), Nereis succinea (N. succinea), and oil-degrading bacteria for cleaning up TPH in spiked sediment. Planting S. heteroptera can greatly increase sediment TPH removal, and its removal was enhanced greater after inoculation with oil-degrading bacteria and/or N. succinea. Moreover, the promising phytoremediation strategy developed in the current work can serve as an efficient, novel approach to removal TPH in sediment/soil. In our opinions, these findings provide insights into the assessment of their ecological risks in the environments that are of interest to broad readership of International Journal of Phytoremediation. [ABSTRACT FROM AUTHOR]

Fast-growing hybrid poplars have been tested for their potential to remove trace elements (TE) from polluted soil in several temperate regions. Despite their potential, they have rarely been tested in countries with a cold temperate climate. The current study screened four different Populus hybrids for phytoextraction of four TEs (i.e., As, Cu, Pb, and Zn) on an abandoned brownfield site in southern Quebec (Canada). The main results showed that under the current experimental conditions, the most important traits determining the actual phytoextraction rate are Biological Concentration Factor (BCF) and TE accumulation in the aboveground biomass, rather than biomass productivity. Although the overall performance of the chosen hybrids was rather poor, the presence of poplar stands enhanced the movement of mobile contaminants in soil, which led to an increase in their concentration in the root zone. This aspect suggests possible strategies for using these plants with high transpiration rates in future phytoremediation projects, including either possible rotation with more effective TE phytoextractor plants (e.g., hyperaccumulators) that can remove high TE amounts that have migrated from the deeper soil layers following poplar plantation, or phytostabilization. Although the use of fast-growing woody species is commonly reported as a feasible option for the phytoextraction of TEs in temperate climates, most available information pertains to only a few species, mostly willows. This is one of the few studies reporting the results of a field test carried out in a cold temperate region, in which different poplar hybrid clones were tested for their potential in TEs phytoextraction. This research determined that although the studied poplar genotypes have no potential under these experimental conditions, the increase in TE concentration observed in the rhizosphere after two years suggests possible alternative phytoremediation strategies (phytostabilization) for managing polluted sites in cold temperate climates. [ABSTRACT FROM AUTHOR]

At present, sanitary landfill is mainly used for domestic waste treatment in Shannan City, Tibet. However, there are few studies on heavy metals in the soil around the landfill in Shannan city. Therefore, the surrounding soil of Luqionggang landfill in Shannan City, Tibet Autonomous Region, is taken as the research object. In the study, the geo-accumulation index method, Nemerow comprehensive pollution index method and potential ecological risk index method are mainly used to evaluate the pollution and risk of heavy metals in the soil around the landfill site. The main results are as follows: The average pH value of the soil around the landfill site is 9.37, belonging to the strong alkaline range. The average values of heavy metals Hg and Ni in soil exceeded the background content, and the average contents of other heavy metals Cu, Pb, Zn, Cr, As and Cd did not exceed the background content. The average content of these eight heavy metals did not exceed the screening value of the national soil environmental quality standard. In the horizontal direction, the average content of heavy metal elements Cu, Cr, Cd, Hg and Ni is relatively high in the west. The average content of heavy metals As, Zn and Pb in the north, east and south is slightly higher than that in the west. And the farther away from the landfill, the less the soil is affected by heavy metals. The evaluation results of geo-accumulation index show that heavy metal Hg is the most affected. The average value of the comprehensive pollution index is 2.969, which is between 2 and 3, belonging to the moderate pollution level. And the west side of the landfill (downstream area) is greatly affected. The evaluation results of potential ecological hazard pollution index show that the potential risk index of single pollutants of heavy metals Cu, Pb, Zn, Cr, Ni, As and Cd belongs to low ecological hazard level, and the potential risk index of single pollutants of heavy metal Hg belongs to relatively heavy ecological hazard level. On the whole, the total potential risk coefficient belongs to medium pollution hazard degree. According to the correlation analysis, there is no significant correlation between heavy metal elements As and Hg and the other six heavy metal elements. In addition, the pollution source of heavy metal As may be mainly soil forming factors and the pollution source of Hg may be mainly human factors. [ABSTRACT FROM AUTHOR]

Red willow, an economically important ornamental shrub in Iran, is characterized mainly by its red stems, making it a valuable ornamental plant in flower markets. This study aimed to investigate the effect of foliar application of methyl jasmonate (MeJA) and ascorbic acid on the morphological and biochemical characteristics of red willow. The experiment was conducted as a completely randomized design with two factors and three replications. Juvenile willow shrubs (3 to 4-year-old red) were cultivated in Hossein Abad village, Markazi province, Iran. The experimental treatments consisted of MeJA (0, 100 and 200 mgL−1) and ascorbic acid (0, 100 and 200 mgL−1). Several traits were evaluated such as the longest branch and two nearest heights, total shrub diameter, the longest branch diameter (at lower, middle and upper parts), total anthocyanin content of the longest branch, salicin content, leaf chlorophyll (a, b and a + b) content, and carotenoid content. In addition, the number, length and width of leaves from the longest branch, fresh and dry weight of branches were analyzed. Results revealed that the application of MeJA and ascorbic acid significantly increased growth characteristics (height, leaf number, total shrub diameter, branch diameter, fresh and dry weight and total anthocyanin content) of red willow shrubs. Furthermore, it was found that 200 mgL−1 treatments of these two substances produced the best results. Red willow shrub growth parameters and yield were also improved by the interaction of these two factors. Additionally, a significant correlation was found between total anthocyanin content and leaf number of the longest branch, total shrub diameter, the height of nearest branch 2 and the plant fresh weight. [ABSTRACT FROM AUTHOR]

Background: Heat stress has adverse effects on the growth and reproduction of plants. Zygophyllum xanthoxylum, a typical xerophyte, is a dominant species in the desert where summer temperatures are around 40 °C. However, the mechanism underlying the thermotolerance of Z. xanthoxylum remained unclear. Results: Here, we characterized the acclimation of Z. xanthoxylum to heat using a combination of physiological measurements and transcriptional profiles under treatments at 40 °C and 45 °C, respectively. Strikingly, moderate high temperature (40 °C) led to an increase in photosynthetic capacity and superior plant performance, whereas severe high temperature (45 °C) was accompanied by reduced photosynthetic capacity and inhibited growth. Transcriptome profiling indicated that the differentially expressed genes (DEGs) were related to transcription factor activity, protein folding and photosynthesis under heat conditions. Furthermore, numerous genes encoding heat transcription shock factors (HSFs) and heat shock proteins (HSPs) were significantly up-regulated under heat treatments, which were correlated with thermotolerance of Z. xanthoxylum. Interestingly, the up-regulation of PSI and PSII genes and the down-regulation of chlorophyll catabolism genes likely contribute to improving plant performance of Z. xanthoxylum under moderate high temperature. Conclusions: We identified key genes associated with of thermotolerance and growth in Z. xanthoxylum, which provide significant insights into the regulatory mechanisms of thermotolerance and growth regulation in Z. xanthoxylum under high temperature conditions. [ABSTRACT FROM AUTHOR]

Evidence for the importance of seedling morphology and the benefits of multi-cropping in tree plantations continues to increase worldwide. The effects of seedling form on the performance of multi-cropped and monoculture plantings of northern red oak and shortleaf pine seedlings were quantified to test the hypotheses that: (1) multi-cropping northern red oak and shortleaf pine seedlings would lead to increased survival and growth of these species, and (2) that the productivity and overall success of mixed oak-pine plantations can be influenced by seedling morphology. Four different form classes of 1–0, bareroot northern red oak seedlings (Short:Thin, Short:Thick, Tall:Thin, and Tall:Thick) were planted with 1–0, bareroot shortleaf pine seedlings at a 2.44 m spacing, with 0.31 m between each planted oak and pine. Adjacent monocultures of shortleaf pine and all form classes of northern red oak were also planted for comparison. Measurements of seedling performance over six years revealed no significant differences in shortleaf pine and northern red oak survival and growth among multi-cropped and monoculture treatments. In contrast, mean height and mean basal diameter in Tall:Thick northern red oak seedlings were significantly greater than in the remaining three northern red oak form classes, regardless of multi-cropping treatment. Survival did not differ among form classes (p > 0.05). These results suggest that seedling morphology was more important than the effects of multi-cropping early on in the development of these plantations, and that further testing of the effects of form class across different multi-cropped species is warranted. [ABSTRACT FROM AUTHOR]

Key message: In mature Q. robur, chlorophyll varied with season and canopy height, whilst eCO2-driven changes were consistent with Marea, highlighting key factors for consideration when scaling photosynthetic processes and canopy N-use. Nitrogen-rich chlorophyll and carotenoid pigments are important in photosynthetic functioning. Photosynthetic pigments have been found to decrease with elevated CO2 (eCO2), but few such studies have been done in aged forest trees. This study aimed to assess the effects of eCO2 (150 μmol mol−1 above ambient) and canopy position on chlorophyll content in mature Quercus robur (Q. robur). Over 5000 in situ chlorophyll absorbance measurements, alongside laboratory chlorophyll extractions, were collected on canopy-dominant Q. robur in the 3rd and 4th season of CO2 fumigation of a free-air CO2 enrichment (FACE) study in central England. Mass-based chlorophyll concentration (Chlmass, mg g−1) was significantly higher in the lower canopy compared to upper canopy foliage (P < 0.05). In contrast, significantly higher chlorophyll content (Chlarea, mg m−2) was observed in the upper canopy. ECO2 did not affect Chlmass but Chlarea significantly increased, attributable to increased leaf mass per unit area (Marea, g m−2). We found no effect of eCO2 on mass-based or area-based nitrogen (Nmass, mg g−1 or Narea g m−2); however, Narea significantly increased with canopy height, again attributable to Marea. The parallel relationships between Marea, Narea and Chlarea suggest the allocation of N to light harvesting is maintained with eCO2 exposure as well as in the upper canopy, and that increased photosynthetic mass may help regulate the eCO2 variation. An understanding of changes in the light-harvesting machinery with eCO2 will be useful to assess canopy processes and, at larger scales, changes in biogeochemical cycles in future climate scenarios. [ABSTRACT FROM AUTHOR]

Purpose: Roots are the mean absorbing organ of plants and an important part of material circulation in ecosystems. Understanding long-term root system development and its response to soil water availability can help to elucidate carbon cycling and plant resource uptake strategies in forest plantations under climate change. Methods: We created a soil water content (SWC) gradient in a poplar forest using irrigation. During the six-year rotation, we determined biomass allocation by dissecting 45 sample trees, and measured spatial–temporal distribution and morphology of fine roots through analysis of 3984 root samples. Observations occurred as stands developed through canopy closure and experienced increasing inter-tree competition. Results: Biomass allocation initially responded positively to low SWC while rooting depth was unaffected. As stands developed, biomass allocation differences gradually disappeared, and low SWC caused deeper root distribution. Morphological responses to depth emerged after the first year. In shallow soil, specific root length and fine-root diameter were lower while root tissue density was greater than those below 50 cm depth. Conclusion: Soil water availability can affect biomass allocation and determine the soil layer with high exploration intensity, but both of these effects depend on stand development. During development, horizontal root system expansion takes precedence over vertical expansion. Besides, our finding implies that functional divergence of fine roots may occur gradually with stand development, with finer diameter roots in shallow soil perhaps functioning mainly for absorbing soil resources while low-density, high-diameter roots in deep soil functioning primarily for expanding the root system and exploring for limiting soil moisture resource. [ABSTRACT FROM AUTHOR]

In this study, relevant variables were determined to predict the probability of sooty mould biofilm (SMB) occurrence on willow leaves in a multivariate model. Despite a large temporal gap between the main sap-feeding insect (SFI) season in spring (May to June) and the main season of SMBs in late summer and fall (August to September), trees infested with SFIs on four or more observation dates had significantly more SMBs (3.7-fold) toward the end of the growing season. In addition, a horizontal leaf position and recessed leaf veins, traits that may increase the wettability of the leaves, positively influenced SMB occurrence (27.8-fold). Among the weather parameters, those that lead to higher moisture on leaf surfaces, namely high morning and evening relative humidity, higher precipitation sums, and lower vapour pressure deficit values, also had the strongest positive effect. In addition to these parameters, higher wind speeds also had a strong positive effect on SMB occurrence. [ABSTRACT FROM AUTHOR]

Ground-level ozone (O 3 ) is the most phytotoxic secondary air pollutant in the atmosphere, severely affecting crop yields worldwide. The role of nanoparticles (NP) in the alleviation of ozone-induced yield losses in crops is not known. Therefore, in the present study, we investigated the effects of biogenicB-AgNPs on the mitigation of ozone-induced phytotoxicity in mung bean and compared its results with ethylenediurea (EDU) for the first time. Two mung bean cultivars (Vigna radiata L., Cv. SML-668 and PDM-139) were foliar sprayed with weekly applications of B-AgNPs (0 = control, 10 and 25 ppm) and EDU (0 = control, 200 and 300 ppm) until maturation phase. Morphological, physiological, enzymatic, and non-enzymatic antioxidant data were collected 30 and 60 days after germination (DAG). The mean O 3 and AOT40 values (8 h day -1 ) during the cultivation period were approximately 52 ppb and 4.4 ppm.h, respectively. More biomass was accumulated at the vegetative phase due to the impact of B-AgNPs and EDU, and more photosynthates were transported to the reproductive phase, increasing yield. We observed that the 10 ppm B-AgNPs treatment had a more noticeable impact on yield parameters and lower Ag accumulation in seeds for both cultivars. Specifically, SML-668 cultivar treated with 10 ppm B-AgNPs (SN 1 ) showed greater increases in seed weight plant -1 (124.97%), hundred seed weight (33.45%), and harvest index (37.53%) in comparison to control. Our findings suggest that B-AgNPs can enhance growth, biomass, yield, and seed quality, and can improve mung bean ozone tolerance. Therefore, B-AgNPs may be a promising protectant for mung bean., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Perennial shrub willow are increasingly being promoted in short-rotation coppice systems as biomass feedstocks, for phytoremediation applications, and for the diverse ecosystem services that can accrue. This renewed interest has led to widespread willow cultivation, particularly of non-native varieties. However, Canadian willow species have not been widely adopted and their inherent diversity has not yet been thoroughly investigated. In this study, 324 genotypes of Salix famelica and Salix eriocephala collected from 33 sites of origin were analyzed using 26,016 single nucleotide polymorphisms to reveal patterns of population structure and genetic diversity. Analyses by Bayesian methods and principal component analysis detected five main clusters that appeared to be largely shaped by geoclimatic variables including mean annual precipitation and the number of frost-free days. The overall observed (HO) and expected (HE) heterozygosity were 0.126 and 0.179, respectively. An analysis of molecular variance revealed that the highest genetic variation occurred within genotypes (69%), while 8% of the variation existed among clusters and 23% between genotypes within clusters. These findings provide new insights into the extent of genetic variation that exists within native shrub willow species which could be leveraged in pan-Canadian willow breeding programs. [ABSTRACT FROM AUTHOR]

Cellulose nanocrystals (CNCs) are renewable, biodegradable and biocompatible nanomaterials that exhibit unique mechanical, optical, rheological and barrier properties useful for a variety of applications. Since CNCs remain an expensive product, coupling its production to pulp and paper products could reduce the production costs. However, pulp and paper mills do not always use a single wood species and so, differences in CNC properties based on the feedstock must be delineated. This work reports on the production and characterization of CNCs from three hardwoods, i.e. white oak, sweetgum and cottonwood, and one softwood, i.e. loblolly pine. Stable aqueous CNC dispersions were obtained from pre-extracted and fully bleached kraft wood pulps. CNC yield (with respect to pulp) ranged between 60 and 80% w/w, and a linear regression model explaining the relationship between CNC yield and pulp cellulose to lignin ratio was found significant (R2 = 0.99 and p value = 0.0044). Sweetgum CNCs had the highest yield and purity, indicating the usefulness of this unconventional raw material for scalable production of high-quality CNCs. Pine CNCs were characterized by the largest length (150–200 nm vs 100–150 nm for the rest), whereas cottonwood CNCs displayed the lowest width (6 nm vs 14–17 nm for the rest) and consequently the highest aspect ratio (~ 20 vs ~8–13 for the rest) as well as the highest Young's modulus (1780 GPa vs 100–300 GPa for the rest). A linear regression model explaining the relationship between Young's modulus and CNC aspect ratio was found significant (R2 = 0.92 and p value = 0.0387). Other physicochemical properties, such as crystallinity index, surface charge, polydispersity index and surface roughness, were similar for CNCs derived from all four species; however, thermal degradation behavior of oak CNCs was slightly different from that of the remaining CNCs (lower Thalf and residual weight). Findings in this study indicate the potential to tune the quantity (yield) and quality (purity and properties) of CNCs based on the type of wood species chosen as the feedstock, thus having a direct impact on production economics and end use in different applications. [ABSTRACT FROM AUTHOR]

Numerous growth and physiological variables of 3-week-old Populus simonii × P. nigra seedlings were assessed after treatment with either nitrate nitrogen (NO3−–N) (0.1, 0.5, 1, 5, or 10 mmol·L−1) or ammonium nitrogen (NH4+–N) (0.1, 0.5, 1, 5, or 10 mmol·L−1) to determine the best nitrogen form and concentration to optimize growth, biomass allocation, pigment content, and photosynthetic capacity. The results of combining membership function and an evaluation index suggested that, 5 mmol·L−1 nitrogen, regardless of the form, yielded the highest comprehensive evaluation index and good growth. In addition, a Pearson correlation analysis and network visualization revealed that the total mass, shoot mass, root mass, leaf dry mass, plant height, leaf area, chlorophyll a and total chlorophyll had a physiological index connectivity degree ≥ 15 for both nitrogen forms. Net photosynthetic rate, stomatal conductance, transpiration rate, maximum photochemical efficiency of PSII, total nitrogen content, ground diameter, chlorophyll b, and carotenoid were unique indices for evaluating NH4+–N-based nutrition, which could provide a theoretical basis for evaluating the effects of nitrogen fertilizer on seedlings, cultivation periods, and stress tolerance in P. simonii × P. nigra. [ABSTRACT FROM AUTHOR]