Objective: This study aimed to characterize the retention of atmospheric particles by different tree species at both the leaf and canopy scales by the analysis of the variation in the retention of atmospheric particles by individual leaves and forest canopies of different tree species under the same pollution background, therefore to provide a theoretical basis for creating urban forests that can efficiently retain atmospheric particles. Method: A survey was carried out on representative scenic recreational forests in plain areas around Beijing’s Fifth Ring Road, five typical scenic recreational forests in the Olympic Park (Pinus armandii-Ginkgo biloba mixed forests, Populus tomentosa-Fraxinus chinensis mixed forests, Salix matsudana pure forest, Populus tomentosa pure forest, and multi-species and multi-layer conifer-broadleaf mixed forest) were selected for the study. The elution-weighing-particle size-analysis method was used to measure the amount of atmospheric particles retained per unit leaf area of each tree species. The leaf area index was used to calculate the amount of particles retained by different tree species per hectare for different particle size categories. Based on the canopy area ratio of individual species to the entire forest, the retention amount of different particle size categories per unit area of pure forest or mixed forest was calculated. Result: There are significant differences in the particle size distribution of atmospheric particles retained by the leaves of different tree species among different forest types. The retention amount of particles per unit leaf area varies among tree species with particle size categories and forest types. At the leaf scale, the comprehensive ranking of the ability to retain atmospheric particles with different particle size categories is: Ginkgo biloba > Juniperus chinensis > Acer truncatum > Koelreuteria paniculata > Pinus armandi > Platycladus orientalis > Fraxinus chinensis > Salix matsudana > Populus tomentosa. The ability of different forest canopies to retain atmospheric particles differs significantly, up to a 20-fold difference. The ranking of the amount of atmospheric particles retained per unit area of different forest types does not change with particle size categories. For all particle size categories, the retention amount is the highest in the Pinus armandi-Ginkgo biloba mixed forest, followed by multi-tree conifer-broadleaf mixed forest, Salix matsudana pure forest, Populus tomentosa-Fraxinus chinensis mixed forest, and Populus tomentosa pure forest. Conclusion: Among the nine tree species studied, Ginkgo biloba, Juniperus chinensis, and Acer truncatum are high dust-retention species; Koelreuteria paniculata, Pinus armandii, and Platycladus orientalis are medium dust-retention species; Fraxinus chinensis, Salix matsudana, and Populus tomentosa are low dust-retention species. Additionally, the study identifies forest structure characteristics that can efficiently retain atmospheric particulate matter: multiple high dust-retention species + multilayered canopy + staggered tree density. To maximize the dust retention effectiveness of urban forests, attention should be paid to both the selection of high dust-retention tree species and the reasonable design of forest structure.

Objective: The balance relationship between carbon absorption and water loss of plantation ecosystems under the arid and semi-arid environment conditions is poorly understood. The understanding of response mechanism of forest ecosystem water use efficiency (WUE) to environmental factors is useful for quantifying carbon and water balance of urban artificial forests. Method: Eddy covariance technology combined with micrometeorological sensors were used to monitor ecosystem carbon and water fluxes and environmental factors of Pinus tabuliformis plantation of Beijing Olympic Forest Park for years 2012—2014, and statistical and simulation methods were used to analyze balance relationship between carbon and water fluxes in plantation ecosystems at the seasonal scale. Result: All 3 years were dry years with little precipitation during the study period, resulting in seasonal soil drought. Annual precipitation values were all lower than the average of the past 60 years and decreased year by year, with total precipitation in year 2014 being only 271 mm. Annual WUE value were 2.2?2.9 g?kg^?1, with the lowest value being 2.2 g?kg^?1 in 2012 and the highest value being 2.9 g?kg^?1 in 2013. During the growing season, WUE was mainly influenced by vegetation index (NDVI), net radiation (R_n), temperature (T_a), soil moisture content (SWC), and saturated vapor pressure difference (VPD). Main environmental factors of seasonal WUE were changing as the following patterns. In spring, NDVI had the greatest impact on seasonal WUE, which explained 48% of spring variations in WUE (P<0.05); in summer, the influence of R_n and T_a had the greatest impacts on seasonal WUE, which explained 52% and 57% of summer variations in WUE, respectively (P<0.05); and in autumn, the influence of SWC and VPD had the greatest impacts on seasonal WUE, which explained 44% and 54% of autumn variations in WUE, respectively (P<0.05). During the growing season, WUE and T_a showed a linear negative correlation (P<0.01); WUE showed a non-linear negative correlation (i.e., logarithmic curve relationship) with VPD and R_n; and WUE showed a linear positive correlation with SWC (P<0.01). However, in extremely dry months, such as May, June, and August of the year 2014, WUE was negatively correlated with SWC (P<0.01), and WUE dropped to its lowest point. In July of years 2012 and 2013, there were consecutive dry periods without rain, and WUE values reached its lowest value of 3.7 g?kg^?1; while WUE values reached its maximum value of 10.3 g?kg^?1, as SWC being increasing, during the continuous precipitation period of the growing season. Conclusion: Carbon and water fluxes of plantation ecosystems under the arid and semi-arid environment conditions have coupled; and seasonal drought and heat have reduced carbon absorption and water loss, and thus, leading to a decrease in WUE. During the dry season of the growing season, in environmental conditions with high T_a, as SWC being decreasing, WUE value has dropped to its lowest level. The combination of available soil water and drought characteristics (i.e., drought intensity and duration) of plantation has affected the seasonal variations of ecosystem carbon and water fluxes, thereby affected the interannual response differences of plantation WUE to drought events, under different temperature conditions during the growing season.

Objective: This paper aims to quantify the carbon and water flux components of eucalyptus plantation ecosystem, reveal the regulatory role of environmental biological factors on carbon and water cycle, so as to provide a basis for improving the accuracy of carbon sink assessment of plantation ecosystem and further understanding the impact of environmental and biological factors on carbon cycle of plantation ecosystem under the background of climate change. Method: The eddy covariance (EC) technique was used to continuously monitor carbon and water fluxes in a typical eucalyptus plantation ecosystem in the northern part of the Leizhou Peninsula. The environmental biological factors such as air temperature (T_air), vapour pressure deficit (VPD), photosynthetic photon flux density (PPFD), soil temperature (T_soil), soil moisture (SM), precipitation (Pre), and normalized difference vegetation index (NDVI) were simultaneously detected. The temporal variation characteristics of ecosystem carbon and water fluxes and their responses to environmental and biological factors were analyzed. Result: Annual average values of total primary productivity (GPP), respiration (RE), net ecosystem carbon exchange (NEE) and evapotranspiration (ET) of eucalyptus plantation ecosystem were 2 907.87, 1 509.77, ?1 398.83 g·m^?2a^?1 and 1 069.25 mm, respectively, showing a carbon sink as a whole. The diurnal variations of GPP, RE, NEE and ET showed asymmetric unimodal trend, and the absolute values of peak value and daily average value were higher in rainy season than in dry season. The accumulated values of GPP, RE and ET in rainy season were higher than those in dry season, while the accumulated values of NEE had no significant difference between dry season and rainy season. The main influencing factor of daytime NEE variation was PPFD. When VPD ≥ 15 hPa, NEE accumulation was inhibited, and the net carbon absorption capacity was strongest at moderate temperatures (20 ℃ < T_air < 27 ℃). Nocturnal NEE changes were mainly affected by T_air, and SM was able to affect the sensitivity of NEE to T_air. Water use efficiency (WUE) was higher in dry season (3.85 g·kg^?1) than in rainy season (2.61 g·kg^?1), with the mean annual WUE of 3.22 g·kg^?1. The seasonal difference was dominated by ET and negatively correlated with T_air, VPD and PPFD (P<0.05). Conclusion: Eucalyptus plantation ecosystem exhibits carbon sinks during the dry season, the rainy season, and the whole year. The carbon sink status and intensity of eucalyptus plantation ecosystem are dominated by GPP. NEE changes are primarily regulated by PPFD, while high VPD inhibits net carbon sequestration. The net carbon sequestration capacity of the ecosystem is strongest at moderate temperature, and SM affects the sensitivity of NEE to T_air changes at night. WUE of eucalyptus plantation is higher in the dry season compared to the rainy season. This seasonal difference is primarily influenced by ET and is also affected by T_air, VPD, and PPFD.

Objective: This paper analyzed the species composition and quantitative characteristics of seedlings in a 60 hm² plot in the tropical mountain rainforest in Jianfengling, Hainan Island, in order to further understand the community species composition and the forest natural regeneration process. Method: This study was conducted in a typical tropical mountain rainforest in Jianfengling, Hainan. The seedling dynamics in 290 sample stations (each with three 1 m×1 m small quadrats) in a 60 hm² plot was monitored for 7 consecutive years (from 2013 to 2019). All seedling species were classified into four life forms, and three mycorrhizal types and species dominance were distinguished respectively. Their species composition and quantitative dynamic changes were analyzed. Result: In the seven years, a total of 60 750 seedlings, belonging to 234 species, were recorded, including four life forms (tree, shrub, liana, and herb). There were three mycorrhizal types, including arbuscular mycorrhiza (AM). ecto-mycorrhiza (ECM), and AM & ECM mixed type. The dominant species, Psychotria asiatica and Cryptocarya chinensis, were widely distributed, occupying the top two positions in terms of importance values, abundance and frequency among all species seedlings. The distribution number of species in each seedling station was uneven. A large part of species only had sparse seedlings. Conclusion: There are abundant species of seedlings in the tropical forests and most of them are rare. This study provides important references for understanding the dynamic changes of seedling species composition, distribution and quantity characteristics at the spatial and temporal scales, and exploring their influencing factors in the future.

Objective: Seed development is genetically programmed and metabolically regulated. Furthermore, water is closely related to metabolism and therefore has a significant regulatory role in seed development. This study aims to provide insights into the movement pattern of water during seed development, by monitoring the spatial and temporal changes of water in Sophora japonica pods at each developing stage with MRI (magnetic resonance imaging) techniques non-destructively. Method: The pods at different developmental stages (30?150 days after flowers) were collected. The morphology of the pods and seeds were observed and measured periodically. Furthermore, the water absorption curves and the seed germination were determined at each stage. Using MRI technology, temporal and spatial water distributions in pods were analyzed. Result: During development, the pods changed from bright green to yellowish-brown. At the same time, the seed coat gradually changed from green to yellow-green, and finally to black. The color variation pattern of different regions of the seed coat was different. According to the MRI image, at 90 days, the hilum region is darkened in perference to other regions. Accompanied by the color change, there was an increase and then a decrease in the sizes of pods and seeds, with the maximum at 90 days and an almost constant size up to 120 days. The change trends of fresh weight of the peels and seeds were the same at all stages: both increased first and then decreased. The dry weight initially increased and then leveled, with the peels peaking at 120 days and the seeds reaching the maximum at 90 days. The moisture content of the peels first increased and then decreased, while that of the seeds continued to decline. The water absorption capacity of seeds varied during development: seeds at 30 and 60 days were susceptible to breakage during imbibition; seeds at later developmental stages were able to imbibition normally, but the time for imbibition to enter into the plateau phase gradually increased in each stage, and the seeds with 90, 120, and 150 days old entered the water absorption plateau phase at 8, 60, and 108 h, respectively; during this process, the germination speed of excised embryos gradually increased, while that of the seeds gradually slowed down. The MRI technique revealed that the water temporal and spatial distribution pattern differed in each tissue of peel, seed coat, gelatinous endosperm, and seed embryo at different developmental stages. At 60 days, the water content was higher in the peel and endosperm, and there were strong signals in the hilum and lens regions of the seed coat too, and the signals disappeared at 90 days. During 90?120 days the signal in the endosperm decreased dramatically, and the water only existed in the embryo at 120 days. Conclusion: The impermeability of the seeds gradually increases during S. japonica seed development. Water transportation from the hilum region and the lens to the peel is interrupted at 90 days, and the seed enters the mature dehydration phase. At 120 days, the seeds are mature and the water content in the seed is low and mainly concentrated in the seed embryo.

Objective: The study is aimed to investigate the effects of Lactarius akahatsu inoculation on the growth, root development, and metabolites of Pinus massoniana and Pinus armandii seedlings, and to provide a scientific basis to cultivate pine mycorrhizal seedlings and symbiotic cultivation of Lactarius akahatsu. Method: Potted seedlings of Pinus massoniana and Pinus armandii were placed in the greenhouse and applied with two treatments of Lactarius akahatsu inoculation and non-inoculation, the difference in the mycorrhizal colonization rate and mycorrhizal dependency, shoot and root growth indicators, the root architecture traits (total root length, root surface area, root volume, root tips, bifurcation), the root morphology traits (specific root length, root tissue density, specific root surface area) and main root metabolites were studied. Result: Evident mycorrhizal morphology of the Lactarius akahatsu was formed in the seedlings of the two pines, and displayed a high mycorrhizal colonization rate and mycorrhizal dependency. The inoculation of Lactarius akahatsu promoted the growth of seedlings to a certain extent, but significant differences were found between the two species. Lactarius akahatsu inoculation significantly increased the plant seedling’s height and dry aboveground weight of Pinus massoniana seedlings, whereas the plant height and dry underground weight of Pinus armandii. The total root length, root surface area, root volume, root tip number, and bifurcation of the two pine species increased by Lactarius akahatsu inoculation, while root vigor and cation exchange capacity decreased. Inoculation with Lactarius akahatsu significantly affected the content of main metabolites in the roots of the two pine species. After Lactarius akahatsu inoculation, the total phenols content and total flavonoid content in the roots of Pinus massoniana seedlings decreased, while the total triterpenoid content, total alkaloid content and total sterol content increased. The trends in metabolites in the root of Pinus armandii seedlings was opposite to that of Pinus massoniana seedlings. Conclusion: Lactarius akahatsu inoculation improves the root morphology and biomass of the seedlings, and affects the content of main metabolites in the roots, and therefore Lactarius akahatsu inoculation is feasible to cultivate pine mycorrhizal seedlings and symbiotic cultivation of ectomycorrhizal fungi.

Objective: This study aims to examine the effects of mixed plantation of Cunninghamia lanceolata and Phoebe chekiangensis on root exudates and community structure of arbuscular mycorrhizal fungi (AMF). The findings would provide theoretical reference for the management and productivity improvement of C. lanceolata plantations. Method: In a pure C. lanceolata forest, a pure of P. chekiangensis forest, and a mixed C. lanceolata and P. chekiangensis forest, soil samples were collected from 0–20 cm soil layer to analyze the differences in root exudates and AMF community structure in the pure and mixed forests, and to elucidate the effects of root exudates in the mixed forest on the community structure of AMFs. Result: Five main types of exudates with high content and allelopathic activity, 2,4-di-tert-butylphenol, dibutyl phthalate, methyl oleate, palmitic acid, and stearic acid, were detected in the soil samples from pure and mixed forests. Among them, the contents of methyl oleate, palmitic acid, and stearic acid varied significantly among different forest types. The number of operational taxonomic units (OTUs) and relative abundance of genera at the OTU level were the highest in the soil of pure P. chekiangensis forest, followed by mixed forest, and the lowest in pure C. lanceolata forest. The dominant genus of AMF in the soils of all three forests was Glomus. The percentage of Glomus was significantly reduced and the percentage of Gigaspora was increased in the mixed forest. Correlation analysis showed that dibutyl phthalate had a greater effect on soil AMF community structure in the C. lanceolata pure forest, and methyl oleate had a greater effect on soil AMF community structure in the mixed forest. Conclusion: The mixed plantation of C. lanceolata and P. chekiangensis results in changes in the content of allelochemicals and affects soil microbiome composition, resulting in significantly higher AMF community diversity and richness compared to pure Chinese fir forest. The results of this study can provide references for the selection of tree species in the“needle to broadleaved forests”conversation from pure C. lanceolata forests, and provide a new theoretical basis and ideas for improving the productivity of needle-broadleaved mixed forests.

Objective: This study aims to analyze the effects of Paxillus involutus on the absorption, assimilation and metabolism of ammonium and nitrate in Populus tremula × Populus alba, and reveal the physiological characteristics of P. involutus in promoting the nitrogen absorption and utilization of P. tremula × P. alba. Method: In this paper, the sand-cultivated P. tremula × P. alba seedlings were inoculated with ectomycorrhizal fungi, P. involutus, to form ectomycorrhiza. Then, normal roots, ectomycorrhiza, and their leaves were used as research objects. The absorption rates of ammonium and nitrate were determined using a non-invasive micro-test technique. The contents of ammonium and nitrate and the activities of nitrogen assimilation enzymes were determined with a spectrophotometer. The transcription levels of nitrogen transporter encoding genes were analyzed by a method of qRT-PCR. Result: After 16 weeks of inoculation with P. involutus, the ectomycorrhiza was emerged in the poplar roots, with the mycorrhizal colonization rate of 55.5%. The net photosynthetic rate of mycorrhizal (M) poplars was significantly higher than that of non-mycorrhizal (NM) poplars. However, there was no significant difference in the total biomass between M poplars and NM poplars. The net influxes of NH₄⁺ and NO₃^- in the root tips of M poplars were increased compared to those of NM poplars. It is worth noting that the inoculation of P. involutus led to change in spatial characteristics of NO₃^? fluxes on poplar roots. The maximum NO₃^? influx point on the poplar roots was shifted from 900 μm to 300 μm due to P. involutus colonization. In line with the results of the ion fluxes, the expression levels of genes involved in NH₄⁺ transport, such as AMT1;1, AMT2;1, and AMT3;2, and genes related to NO₃^? transport, such as NPF1.2F, NPF2.11A, and NPF6.3, were higher in the roots of M poplars than those in NM poplars. Meanwhile, the increase in transcript levels of genes involved in NH₄⁺ transport was stronger than that of genes related to NO₃^? transport in the roots of M poplars. Correspondingly, the contents of NH₄⁺ and NO₃^? in the roots and leaves of M poplars were higher than those of NM poplars. In addition, the activities of enzymes including glutamine synthase (GS), glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH), which are involved in NH₄⁺ assimilation, were increased significantly in the roots and leaves of M poplars in comparison with NM poplars. Inoculation with P. involutus caused a significant increase in the total nitrogen in the roots and a significant decrease in the total carbon in the leaves of M poplars, resulting in significantly lower C/N levels in the roots and leaves of M poplars than those of NM poplars. Conclusion: These results suggest that the ectomycorrhizal fungus, P. involutus, enhances the nitrogen nutrition of its host P. tremula × P. alba by mainly increasing the absorption, assimilation and metabolism of ammonium nitrogen.

Objective: This study aims to explore the influence of soil microorganisms on the rhizosphere microbiota characteristics of Caragana korshinskii under nitrogen deposition background, and explore the regulatory rules of microbiota changes on the morphological construction of C. korshinskii root system, so as to provide theoretical basis for ecological restoration of fragile ecosystems. Method: On the basis of soil sterilization treatment (sterilized soil (+S) and non-sterilized soil (-S)), 1-year-old potted C. korshinskii seedlings were subjected to two kinds of inoculation experiments (mixed inoculation with Rhizophagus intraradices and Funneliformis mosseae (+M), and non-inoculation treatment (?M)), and three nitrogen addition treatments (no nitrogen application (0N, 0 g·m^?2a^?1), low nitrogen (LN, 3 g·m^?2a^?1), high nitrogen (HN, 6 g·m^?2a^?1)). After the end of the growing season, the soil microbial biomass, soil enzymes activity related to nutrient conversion, soil nutrient content, and seedling fine root morphology with diameter ≤ 0.5 mm (total root length, total surface area, total volume and number of root tips) of each treatment were analyzed, the correlation between micro ecological environment changes and root morphology construction was explored. Result: 1) In both 0N and LN treatments, the microbial biomass carbon content in rhizosphere soil of C. korshinskii in non-sterilized soil was higher than that in sterilized soil. In HN treatment, the soil microbial biomass carbon content of non-mycorrhizal seedlings was the lowest in sterilized soil. In sterilized soil with different nitrogen addition treatments, the activity of carbon conversion related enzymes in rhizosphere soil of mycorrhizal seedlings was higher than that of non-mycorrhizal seedlings (P<0.05), while the soluble carbon content in rhizosphere soil of C. korshinskii in non-sterilized soil and inoculation treatment was higher than that in the single treatment (P<0.05). 2) Under different nitrogen addition treatments, the nitrogen content of rhizosphere soil microbial biomass of non-mycorrhizal seedlings of C. korshinskii in non-sterilized soil treatment was significantly higher than that in sterilized soil treatment (P<0.05), and the activity of nitrogen conversion related enzymes in rhizosphere soil of C. korshinskii in the interaction of non-sterilized soil treatment and inoculation treatment was significantly higher than that in the single treatment. Under LN and HN treatments, the rhizosphere available nitrogen content of non-mycorrhizal seedlings in soil sterilization was significantly higher than that in other treatments (P<0.05). 3) Under HN treatment, the phosphorus content and alkaline phosphatase activity of microbial biomass in rhizosphere soil of C. korshinskii in the interaction of non-sterilized soil and inoculation treatment were significantly higher than those in other treatments (P<0.05), and the available phosphorus content in rhizosphere soil in the interaction of non-sterilized soil and inoculation treatment was between the single effects of non-sterilized soil and inoculation treatment. 4) Under HN treatment, the root morphological indexes of C. korshinskii mycorrhizal seedlings in sterilized soil were the highest. Under 0N treatment, the root morphological indexes of non-mycorrhizal seedlings in non-sterilized soil were the smallest. 5) The redundancy analysis results showed that microbial biomass carbon content had the highest explanatory degree in the key regulatory factors affecting the root morphology of seedlings, and it had a positive regulatory effect. The results of multiple linear regression analysis showed that alkaline phosphatase activity had the greatest influence on seedling root morphology, and it showed a negative regulatory effect. Conclusion: Under the background of exogenous nitrogen input, the synergistic effect of non-sterilized soil treatment and seedling inoculation treatment is conducive for maintaining the balance of plant rhizosphere microhabitat, and the limiting factor of rhizosphere microhabitat in high nitrogen treatment is transformed into phosphorus element. The root growth of C. korshinskii seedling is promoted by inoculation treatment, but is restricted by soil sterilization treatment. The root growth is closely related to soil carbon and phosphorus cycles process. The root morphological construction is positively regulated by boil microbial biomass, but it is negatively regulated by phosphorus transformation related enzymes.

Objective: This study conducts a functional analysis of the SNARE protein Nyv1, which regulates vesicle transport in Cytospora chrysosperma, to explore its mechanism of action in the growth, development, and pathogenic processes of the fungus. It provides an important reference for understanding the regulatory mechanism of SNARE proteins in the pathogenic process of C. chrysosperma and for developing effective prevention and control strategies for this disease. Method: 1) Utilizing the amino acid sequence of Nyv1 from Saccharomyces cerevisiae for Blastp analysis to identify its homologous CcNyv1 gene. 2) Using bioinformatics software to perform multiple sequence alignments of the amino acid sequence encoded by CcNyv1 and homologous Nyv1 sequences in other fungi, and to construct a phylogenetic tree. 3) Employing the split-marker method and PEG-mediated genetic transformation system to obtain CcNyv1 gene deletion mutants and complemented strains. 4) Observing mycelial growth rate through PDA plate growth experiments, and analyzing whether the CcNyv1 gene, along with Longin and SNARE domains, affect the nutritional growth of mycelia and their response to salt stress. 5) Observing the expansion of disease spots on scalded branches of one-year-old poplars to assess the impact of the CcNyv1 gene, along with Longin and SNARE domains, on the pathogenicity of the poplar rot fungus. 6) Employing FM4-64 dye staining to investigate whether the CcNyv1 gene and the Longin, SNARE domains affect the endocytosis of the fungus. Result: 1) Through a Blast comparison using the amino acid sequence of Saccharomyces cerevisiae Nyv1, its homologous gene CcNyv1 was identified in C. chrysosperma. This gene is 780 bp long, contains one intron, and encodes a 233 amino acid vesicle transport-related R-SNARE protein, which includes an N-terminal Longin domain and a C-terminal SNARE domain. 2) Multiple sequence comparisons and phylogenetic analyses show that CcNyv1 and its homologous Nyv1 genes in ascomycetes have a high degree of sequence similarity, are evolutionarily conserved, and the CcNyv1 in C. chrysosperma is most closely related to the homologous gene in Cryphonectria parasitica. 3) Using the split-marker method, CcNyv1 gene deletion mutants, Longin domain deletion mutants, SNARE domain deletion mutants, and CcNyv1 gene complemented strains were obtained. 4) Analysis of mycelial growth phenotype and pathogenic phenotype on poplar branches shows that the CcNyv1 gene deletion mutants and Longin, SNARE domain deletion mutants exhibit significant defects in mycelial nutritional growth, response to salt stress, and pathogenicity. 5) Comparison of vesicle distribution in wild-type and deletion mutant strains stained with FM4-64 reveals that the CcNyv1 gene and Longin, SNARE domains affect the endocytosis of C. chrysosperma. Conclusion: The SNARE protein CcNyv1 of C. chrysosperma plays a significant regulatory role in aspects such as nutritional growth, stress response, pathogenicity, and endocytosis.

Objective: As for the problems of low utilization of forestry text, insufficient understanding of forestry knowledge by general-domain pre-trained language models, and the time-consuming nature of data annotation, this study makes full use of the massive forestry texts, proposes a pre-trained language model integrating forestry domain knowledge, and efficiently realizes the forestry extractive question answering by automatically annotating the training data, so as to provide intelligent information services for forestry decision-making and management. Method: First, a forestry corpus was constructed using web crawler technology, encompassing three topics: terminology, law, and literature. This corpus was used to further pre-train the general-domain pre-trained language model BERT. Through self-supervised learning of masked language model and next sentence prediction tasks, BERT was able to effectively learn forestry semantic information, resulting in the pre-trained language model ForestBERT, which has general features of forestry text. Subsequently, the pre-trained language model mT5 was fine-tuned to enable automatic labeling of samples. After manual correction, a forestry extractive question-answering dataset comprising 2 280 samples across the three topics was constructed. Based on the dataset, the six general-domain Chinese pre-trained language models of BERT, RoBERTa, MacBERT, PERT, ELECTRA, and LERT, as well as ForestBERT that was specifically constructed in this study were trained and validated, to identify the advantages of ForestBERT. To investigate the impact of different topics on model performance, all models were fine-tuned on datasets related to the three topics: forestry terminology, forestry law, and forestry literature. Additionally, a visual comparison of the question-answering results in forestry literature between ForestBERT and BERT was performed to more intuitively demonstrate the advantages of ForestBERT. Result: ForestBERT outperformed the other six comparison models in forestry extractive question-answering task. Compared to the base model BERT, ForestBERT improved the EM score and F1 score by 1.6% and 1.72%, respectively, and showed an average performance improvement of 0.96% over the other five models. Under the optimal division ratio for each model, ForestBERT outperformed BERT and the other five models in EM score by 2.12% and 1.2%, respectively, and in F1 score by 1.88% and 1.26%. Additionally, ForestBERT excelled in all three forestry topics by 3.06%, 1.73%, 2.76% higher than the other five models in evaluation scores for terminology, law, and literature tasks. In all models, the performance was the best in the terminology task, with an average F1 score of 87.63%, and the lowest in the law task, which still reached 82.32%. In the literature extractive question-answering task, ForestBERT provided more accurate and comprehensive answer compared to BERT. Conclusion: Enhancing the domain-specific knowledge of forestry in general pre-trained language model through further pre-training can effectively improve the accuracy of the model in forestry extractive question-answering task, which provides a new approach for processing and applying texts in forestry and other fields.

Objective: 1) Evaluate the effects of linear and nonlinear model forms of the model, as well as residual assumptions on inferential uncertainty. 2) Compare two methods of estimating variance of the population mean-bootstrap and analytical method. 3) Assess the effects of multiple factors on inferential uncertainty, and construct empirical rules of statistical inference based on remote sensing models to guide practice. Method: 160 sample plots were selected from the population using a two-stage sampling design. The variable of interest was denoted by forest volume as an example. Under the model-based inference, based on the measured sample plots of firewood volume in African savannahs and Landsat 8 remote sensing auxiliary data, the population parameters were estimated under different modeling assumptions, which aimed to quantitatively analyze the effects of analytical parameter model assumptions on estimating uncertainty and using diagnostic methods such as confidence ellipses to ensure the validity of the analysis. Result: 1) Under the different model assumptions, the population mean estimates $ {\hat{\mu }}_{\mathrm{m}\mathrm{b}} $ ranged from 7.159 to 7.331 m³·hm^?2. Analytical variance of the population mean estimates $ {\widehat{\mathrm{V}\mathrm{a}\mathrm{r}}(\hat{\mu }}_{\mathrm{m}\mathrm{b}}) $ ranged from 0.147 to 0.221. The sampling precision ranged from 93.59% to 96.64%. Empirical variance of the population mean estimates $ {\widehat{\mathrm{V}\mathrm{a}\mathrm{r}}(\hat{\mu }}_{\mathrm{b}\mathrm{o}\mathrm{o}\mathrm{t}}) $ ranged from 0.143 to 0.237. Model assumptions will affect inferential the estimation of model parameters, which will ultimately affect inferential precision $ {\widehat{\mathrm{V}\mathrm{a}\mathrm{r}}(\hat{\mu }}_{\mathrm{m}\mathrm{b}} )$. The bootstrap method is an effective method for testing the unbiasedness of the analytical estimate of population parameters; 2) Under design-based inference, the estimated mean $ {\hat{\mu }}_{\mathrm{d}\mathrm{b}} $ was 6.774 m³·hm^?2 with a variance $ {\widehat{\mathrm{V}\mathrm{a}\mathrm{r}}(\hat{\mu }}_{\mathrm{d}\mathrm{b}}) $ of 0.965, the sampling precision is 85.50%. Under established conditions, compared with design-based inference, model-based inference effectively increased the inferential precision by 77.10%-84.77% and improved the sampling precision between 9.46%-13.03%. Conclusion: Model-based inference has higher inferential precision and sampling precision in small sample inference, which is conducive to achieving the goal of high-precision, small-sample size and short-period forest inventory, but the uncertainty in the modeling process will affect inferential precision, among which the residual variability has the greatest influence on the inferential uncertainty. Ignoring spatial autocorrelation to infer population parameters under homogeneous variance assumptions will underestimation of $ {\widehat{\mathrm{V}\mathrm{a}\mathrm{r}}(\hat{\mu }}_{\mathrm{m}\mathrm{b}} )$. Therefore, it is important to account for the spatial autocorrelation apart from taking the heteroscedasticity into the estimation of model parameters using appropriate variance and correlation functions.

Objecive: Aiming at the problem of missed and misdetection of targets due to the inconspicuous features and variable scales of early pine wood nematode infestation in UAV (unmanned aerial vehicle) forest images, this paper proposes a detection method for early pine wood nematode infestation. Method: Firstly, in order to facilitate the deployment at the airborne end of the UAV, this paper proposes a pine wood nematode infestation detection method that reduces the amount of computation and the number of parameters; secondly, in order to obtain more accurate features of early pine wood nematode infestation, the method uses multiple ways of simultaneous extraction of features and fusion to enhance the learning ability of effective features; then, in order to further improve the fusion ability of features at different scales, the method uses the attention mechanism to Aligning the adjacent two levels of features; finally, taking the early pine nematode infestation photographed by UAV in Dahuofang experimental forest in Fushun, Liaoning Province as the object of study, the LablImg open source software was used to annotate the images captured at the heights of 100?240 m, and to construct the early pine nematode infestation images (EPI) (early pine wood nematode infestation) dataset. Results: The test results on the EPI dataset showed that the Average Precision (AP) of this paper's method reached up to 95.2%, which was improved by 3.1%, 4% and 0.9% compared with the AP of YOLOv5s, YOLOX-s and YOLOv6s, respectively; the volume of the model was only 12.8 M, which was the volume of YOLOv5s, YOLOx-s and YOLOv6s, respectively, 23.6%, 17.8% and 8.9% of the model volume of YOLOX-s and YOLOv6s, respectively. Conclusion: In summary, the method in this paper has high recognition accuracy while keeping the model volume small, which provides the possibility for UAVs to recognize early pine wood nematode infestation at the airborne end.

Objective: Acer truncatum is a precious economic forest tree species in China, and its seed oil contains rich nervonic acid and other substances, which is vital for preventing and treating human neurological diseases. However, in recent years, we have found that A. truncatum seeds have been severely damaged by the larvae of a Cecidomyiid species, Acumyia sp. (Diptera). The present study aims to investigate and identify the natural enemies of Acumyia sp. for environmentally friendly pest management. Method: Through field investigations in Beijing and Inner Mongolia, as well as indoor rearing, a chalcid wasp that parasitizes and preys on the larvae and pupae of Acumyia sp. was discovered. A taxonomic study was subsequently conducted, revealing the parasitoid as a new species, Systasis aceri Yang, Liu et Cao sp. nov., which belongs to the genus Systasis (Hymenoptra, Chalcidoidea, Pteromalidae). In this paper, the new species is described in detail, and color photos are provided. Additionally, the biology of this wasp is reported and compared with other related species. Result: This new species is similar to a parasitic wasp in China, Systasis obolodiplosis Yao et Yang, also a Cecidomyiid parasitoid, but can be distinguished by the following characters: the new species has a golden-green body color, with female body length of 3.4–3.6 mm and male body length of 1.8–2.4 mm (whereas the latter has a blue body with a purple metallic tint; female body length of 2.1 mm and male body length of 1.3 mm); the clypeus shape is square-like with width 1.4 times its height (the latter’s clypeus is much wider, with a width 2.0 times its height); the gaster is long, with a length 2.7 times of its own width (the latter’s gaster is shorter, with a length only 1.8 times its width). Xiao & Huang revised the species of the genus Systasis in China and provided a key to nine species. Using this key, the new species was initially misidentified as Systasis procerula Xiao et Huang. However, the female of the new species differs in other characteristics: post-marginal vein length is 1.4 times the stigmal vein (the latter’s post-marginal vein is shorter than the stigmal vein); antenna is shorter, with the length of pedicel plus flagellum being 1.15 times the head width (the latter is 1.4 times the head width); gaster is much longer, with a length 2.7 times its own width (the latter’sgaster is shorter, with a length only 1.5 times its width). Additionally, the biology of the new species is discussed. The parasitism rate of the new species on the larvae and pupae of Acumyia sp. was about 36%. Its 1st–2nd instar (when they were young and smaller) larvae were parasitic, while the 3rd instar (when they grew larger) and later larvalstages became predatory, capable of preying on 35?52 Acumyia sp. larvae (or puparium) within a single seed. Usually there were 60?126 individuals of the cecidomyiid larvae fed in a single seed and 4?6 parasitoid larvae parasitized/preyed. However, only 1?3 wasps finally emerged. The wasp occurs 2 generations per year and is a preliminary natural enemy of Acumyia sp. Conclusion: The discovery of this natural enemy provides an excellent biological control agent for the Acer seed pest Acumyia sp. This finding is important for protecting the precious tree species A. truncatum and its seed oil resources, offering a potential technique for future biological control of the seed pest.

Objective: In order to provide reliable methods and scientific basis for the modification of poplar wood surface and the optimization manufacturing process of wood scrimber, the directional recombination technology was applied to manufacture the wood scrimber of poplar with high-hardness, and then the effect of compression ratios (CR) on the surface hardness of wood scrimber was studied. Method: The wood scrimber with compression ratios of 50%, 55% and 59% were prepared by the directional recombination technology, and the poplar, beech and Russian oak were taken as the control samples. The values of Janka hardness was measured by the universal mechanical testing machine. And the macroscopic and microscopic morphology of samples, as well as the damaged surface for samples during the testing process of Janka hardness were observed by ultra-depth-of-field three-dimensional microscope (UDTM) and field emission scanning electron microscope (SEM). Additionally, the porosity of the samples was tested by mercury injection porosimetry (MIP) and distribution of phenol-formaldehyde resin (PF) within the wood scrimber was characterized by laser scanning confocal microscopy (LSCM) and transmission electron microscopy (TEM). Result: The Janka hardness values of wood scrimber increased with increasing compression ratios. The Janka hardness value of wood scrimber with compression ratio of 59% increased by 12.63 times compared with that of poplar wood. Furthermore, the Janka hardness value of wood scrimber was much higher than those of Russian oak and beech. In practical applications, the appropriate compression ratio of the wood scrimber can be determined according to the needs in different area. The analysis of stress-strain curve of Janka hardness showed that the proportional ultimate stress of wood scrimber increased with increasing compression ratio. The observation of SEM and UDTM revealed that the failure surface of poplar wood was ductile fracture, but changed to brittle fracture for the wood scrimber. The porosity of the samples tested by MIP showed that directed recombination technology significantly reduced the porosity of poplar wood, and the porosity of the wood scrimber decreased with increasing compression ratio. The observation of LSCM and TEM showed that the width and depth of PF resin distributed along the glue layer band gradually increased with increasing compression ratio and penetrated into the vessel, wood rays and fiber cells. The cell wall mechanical properties of the wood scrimber were tested by nanoindentation. When the compression ratio of the wood scrimber was 55% and the resin content was 15%, the hardness and elastic modulus of the cell wall were increased by 54.65% and 20.14% compared with the poplar wood, respectively. The reasons for the increase in surface hardness of wood scrimber were as following: In the manufacturing process, the vessels and fiber cells of poplar wood were compressed, and the porosity of wood scrimber was reduced. Therefore, the parenchymal density of wood cells in per unit volume was increased. Additionally, the binding area between the wood cells is increased and the connections are tighter. Meanwhile, the PF not only fixed the compressed cell structure, but also increases the strength of the connection between the wood cells through the formed glue nails, the PF resin immersed in the cell wall also enhanced its hardness and elastic modulus, which effectively improved the surface hardness of the wood scrimber. Conclusion: The directional recombination technology can be applied to solve the soft problem and low surface hardness of poplar wood, and the surface hardness of the wood scrimber can be adjusted through the compression ratio, so that the products prepared by the directional recombination technology can meet the needs of different applications.

Objective: The variations of water vapor sorption behavior of wood was investigated during cyclic adsorption-desorption processes, aiming at clarifying the response mechanism of wood cell wall and its adsorbed water to the cyclical humidity variation, and providing theoretical guidance and data reference for the actual usage and rational development of wood. Method: The moisture adsorption/desorption isotherms of Chinese fir (Cunninghamia lanceolata) and masson pine (Pinus massoniana) were measured synchronously by Dynamic vapor sorption analysis during three or five adsorption-desorption cycles among 0% to 95% to 0%. The equilibrium moisture content (EMC) data of samples in the adsorption process were nonlinearly fitted by H-H model. Result: 1) Before and after the sorption cycles, the maximum EMC of samples showed a decreasing trend, and the difference value was ranged from 0.21% to 1.76%. The EMC in the initial cycle was lower than that in the subsequent cycles, especially between 40% and 95% relative humidity. 2) With the increase of the number of sorption cycles, the time required for one single sorption cycle of samples decreased, and the reduction degree also became obviously smaller. Compared with the solid samples, the single sorption cycle of the powder samples required less time. 3) The hygroscopic hysteresis of samples in the initial cycle was more obvious than that in the subsequent cycles. The maximum value of absolute hysteresis decreased and the mean hysteresis coefficient increased with the increase of the number of sorption cycles. 4) The H-H model could be used to describe the water adsorption isotherms of samples during the sorption cycles with R² above 0.996. With the increase of the number of sorption cycles, the parameter W which means the apparent molecular mass of the absolute dry wood per sorption sites decreased, the maximum amount of monolayer molecules water increased, and while the maximum amount of polylayer molecules water and the total amount of adsorbed water decreased. Conclusion: With the increase of the number of sorption cycles, the response of wood cell wall to cyclical humidity variation of samples were weakened: the hygroscopicity of samples decreased, and the maximum EMC showed a decreasing trend; the time required for one single sorption cycle was reduced; and the hygroscopic hysteresis of samples decreased.

Objective: Identifying the compositions and odor characteristics of odor-active compounds emissions from Pinus massoniana woods, and analyzing sources and release mechanisms will be helpful to provide guidance for the construction of the odor database and scientific utilization of Pinus massoniana woods as materials in landscape design. Method: Emission characteristics of odor-active compounds from heartwoods and sapwoods with different moisture contents were researched via gas chromatography-mass spectrometry-olfactometry in this paper. Result: In total, 25 substances were successfully identified. The main odorants were α-pinene (dense pine wood), camphene (mint, pungent), limonene (fresh, lemon), longifolene (cooling) and (+)-cycloisosativene (fresh). The main components of odor compounds from Pinus massoniana woods were terpenoids, alcohols, hydrocarbons and aldehydes. Terpenoids accounted for 90.99%?96.58% of the total odorants, followed by alcohols and hydrocarbons. The odour attributes of Pinus massoniana timbers were mainly mint-camphor, fresh floral and woody aromas, accompanied by fruity and sweet fragrance, and occasionally presented a weak of almond and leather-mixture aroma. With the decrease of moisture content, the total mass concentrations and odor intensities firstly increased and then decreased. The species, concentrations and intensities of odor-active compounds from sapwoods were higher than those from heartwoods. For example, when the moisture content was 30%, concentrations and intensities of odor-active compounds from sapwoods were 6.76 times and 1.77 times of those from heartwoods, respectively. Terpenoids, alcohols, hydrocarbons and aldehydes also existed in sapwoods, whereas only terpenoids and hydrocarbons were detected stably in heartwoods, occasionally followed by a few of alcohols emissions. The concentration of compound monomer was correlated with wood moisture content, and the result for the same substance was different due to the diversity of heartwood and sapwood. In general, there was a positive correlation between the concentration and odor intensity of the same compound monomer, which was related to compound specie, wood location and wood moisture content. Conclusion: The odour attributes were mainly mint-camphor, fresh floral and woody aromas, modified by fruit and sweet smell, which had relax and happy effect on psychological feeling. Therefore, as the important landscape material, Pinus massoniana wood has a positive effect on the use’s mental and physical health, and is proper for use in most urban parks, children’s parks, and healing landscapes.

Sustainable forest management and related optimal rotation decision are important ways to mitigate global climate change. Due to the basic assumption of the classical Faustmann model that all parameters are consistent in different rotation cycles cannot be satisfied, it is necessary to explore the optimal rotation decision-making problem under the influence of multiple factors based on the generalized Faustmann model. This study focuses on the generalized Faustmann model, summarizes its theoretical expansion and frontier application, and analyses the research frontier of the generalized Faustmann model in sustainable forest management decision-making methodology. The research finds that: 1) The generalized Faustmann model has been expanded in four directions, carbon sequestration benefits, uneven-aged forest management, natural risk and tax policy, among them, the land expectation value and the corresponding first-order conditions for profit maximization can help forest owners to formulate a reasonable forest management plan. 2) By using the generalized Faustmann model, the quantity growth rate, quality growth rate and price growth rate in the Pressler indicator rate can be specified, it allows forest owners to make decision in advance in conjunction with their own risk preferences to decide whether to cut the stand in the current year. 3) The land value and timber value of the forest can be clearly distinguished under the generalized Faustmann model, so that when transferring an immature forest, the accurate valuation of forest land and timber can be achieved, and their respective tax rates can be determined under different tax policies. The extension direction of the generalized Faustmann model in the future optimal rotation decision-making research also includes the following aspects: 1) Expanding carbon sequestration benefits from aboveground biomass carbon pool to complete forestry carbon pools. 2) Expanding tax policies from foreign policies to the forestry tax and fee system with Chinese characteristics. 3) Extending model assumptions from deterministic environments to stochastic environments. 4) Expanding the research scale from stand-level to forest-level. 5) Expanding ecological benefits from carbon sequestration benefits to forest ecosystem services.

Waterlogged wooden cultural relicsrepresented by ancient shipwrecks, waterlogged wooden wares and wooden slips serve as carriers of ancient human civilization. They are valuable physical materials for studying Chinese ancient history, art, technology and economy. Accurately understanding the preservation state of waterlogged archaeological wood (WAW) is an important prerequisite and basis for the scientific protection and preservation of waterlogged wooden cultural relics. However, due to the influence of long-term water burial conditions, the structure and properties of WAW have significantly deteriorated. Not only the scientific theory and evaluation system of existing sound wood are difficult to apply, but also the difficulty of obtaining, preparing, testing and analyzing WAW samples is much greater than that of sound wood. This paper systematically reviews the main research progress of waterlogged wooden cultural relics at home and abroad. Firstly, the structural characteristics and analysis methods of waterlogged archaeological wood are introduced from four aspects: anatomical structure, chemical structure, relative crystallinity and pore characteristics. Secondly, the physical, chemical and mechanical properties and characterization methods of WAW are described. The comprehensive evaluation principles, methods and key indicators of the structure and properties of waterlogged archaeological wood are further discussed. Finally, based on the current situation, needs and difficulties of waterlogged wooden cultural relics protection research, three aspects of research that should be prioritized in the future are proposed: 1) To innovate the non-invasion research methods of waterlogged archaeological wood, and establish the evaluation technology and standard system of waterlogged wooden cultural relics. 2) Improve the convenience and reliability of scientific data obtention of waterlogged archaeological wood, and improve the information resources and sharing system construction of waterlogged wooden cultural relics. 3) Construct the structure-properties relationship between the structure and properties of waterlogged archaeological wood, and improve the theoretical system of wood science suitable for waterlogged wooden relics. By further strengthening the evaluation of the preservation state of waterlogged archaeological wood, it can promote the application of new technologies, new methods and new consolidants in the field of waterlogged wooden cultural relics, and provide theoretical basis and technical support for the scientific protection and long-term preservation of wooden cultural relics.