Hydrogels are polymeric materials composed of hydrophilic polymers that form a three-dimensional network structure through chemical or physical cross-linking. They typically possess characteristics such as flexibility, hydrophilicity, and elasticity, and are widely used in fields like biomedical engineering, flexible electronics, and smart materials. Traditional hydrogels are mostly made from fossil-based polymers, which are non-renewable and can be toxic to some extent. These polymers may pose potential threats to human health and the environment during use and recycling. Most hydrogels are synthesized by polymerization or assembly of molecular components uniformly dissolved in an aqueous medium. The resulting polymer networks are usually isotropic and prone to mechanical failure under prolonged external forces. In recent years, researchers have been committed to combining materials with hierarchical anisotropic structures with organic and inorganic phases at the nanoscale to fabricate hydrogels with significant mechanical properties and biological functions, as well as oriented structures. However, the preparation of such hydrogels remains a major challenge. Wood is an abundant, natural, and renewable biomass resource with unique multi-scale hierarchical anisotropic structures, oriented cellulose nanofibers, and porous characteristics, making it a promising candidate for hydrogel fabrication. Moreover, the cellulose fibers in wood have high strength and modulus, which can enhance the mechanical properties of hydrogels when used as reinforcing phases. The natural porous structure of wood provides a basis for preparing highly absorbent hydrogels. Additionally, the presence of many functional groups in wood, such as hydroxyl groups, facilitates various chemical modifications and offers the possibility of tailoring the properties of hydrogels according to different application needs. Based on this, in recent years, researchers have chemically treated wood to obtain hydrophilic fibrous frameworks. They then infiltrate polymers into the microchannels of wood and cross-link them with other polymers to form wood-based hydrogels with natural fibrous structures in situ. These hydrogels not only possess the flexibility and tunable physical and chemical properties of traditional hydrogels but also leverage the anisotropy, excellent mechanical properties, and green degradability of wood. This study analyzes the interactions between wood components (cellulose, hemicellulose, lignin) and water molecules to summarize the preparation methods of wood-based hydrogel frameworks and the characteristics of different types of wood-based hydrogels. It also elucidates the cross-linking mechanisms within wood-based hydrogels. Furthermore, it reviews the current applications of wood-based hydrogels in biomedical engineering, flexible electronics, and smart materials. Based on the relevant research achievements in wood-based hydrogels, this study identifies the challenges that need to be addressed at the current stage and provides an outlook on the future research trends in this field.

Objective: Global climate change has altered precipitation patterns, and tree mortality caused by drought is a magnitude threat to global forest ecosystems. The impact of severe seasonal drought on Cunninghamia lanceolata plantations in southern China has become a hot topic in ecological research. However, the investigation into the damage characteristics and influencing factors of extreme drought on subtropical Chinese fir mixed forests remains limited. This article aims to explore which types of forest stands are more susceptible to the impact of drought, the key influencing factors of tree damage or death caused by drought, in order to provide theoretical support for subtropical forest management in the context of global change. Method: An extreme drought event occurred in southern China in 2022, with the opportunity, this study targeted at mixed plantations of C. lanceolata and Phoebe bournei with similar age. Three plant plots were set up in each of two types of slopes of steep slope and gentle slope, and two types of mixed patterns of mixed plantations with two tree species and mixed plantations with three or more than three tree species. The species composition, diameter at breast height (DBH), tree height, damage rate of individual trees and soil physical properties in the plots were investigated, the characteristics of the extreme drought climate occurred in southern China in 2022, the stand damage rate at various slopes, the composition of damaged trees, and the influencing factors were analyzed. Result: Slope had a greater effect on soil aggregates, while the mixed type of plantations had no effect on soil aggregates. The mixed type had a significant effect on surface (0–20 cm) soil porosity, soil bulk density, maximum water holding capacity, capillary water holding capacity and minimum water holding capacity, and the effect decreased with the increase of soil depth. Different slopes had no significant effect on above these indexes. The drought resulted in varying degrees of damage to trees, with an average damage rate of 29.18%. Among them, mild damage accounted for 15.46%, moderate damage for 2.42%, and severe damage for 11.3%. The severely damaged trees mainly consisted of dominant species in the canopy and understory regeneration layers, with broadleaf trees being more severely impacted than coniferous trees, and planted species more affected than natural regenerating species. Slope gradient and position had the greatest impact on tree damage rates, along with factors such as stand density, soil bulk density, soil aggregate stability index (SASI), elevation, total porosity of the 20 cm soil layer, maximum water holding capacity of soil, and capillary water holding capacity. Conclusion: The extreme drought occurred in southern China in 2022 has demonstrated the characteristics of altered precipitation patterns under global climate change. The mixed plantations with multiple advantageous species are beneficial for improving the drought resistance of forests. Steep slopes and uphill areas are more susceptible to drought, and the impact of drought on forests is the result of multiple factors interacting. In future management of subtropical forests, priority should be given to constructing mixed forests with multiple tree species, determining reasonable stand density, and strengthening surface soil management.

Objective: Taking the seedlings of 10 main tree species in the Northeast Forest as the research object, this study explores the response differences of leaf functional traits to nitrogen addition. The aim is to clarify the adaptation strategies of different tree species to nitrogen deposition and provide a scientific basis for nitrogen deposition management in the forest ecosystem of this region. Method: In the biodiversity control experimental plot in Shulan, Jilin, a study was conducted to investigate the effects of nitrogen addition on leaf functional traits of 2-to 3-year-old saplings from 10 major tree species commonly found in northeastern forests, namely Betula platyphylla, Pinus koraiensis, Juglans mandshurica, Maackia amurensis, Phellodendron amurense, Quercus mongolica, Acer pictum subsp. mono, Fraxinus mandshurica , Tilia amurensis, and Picea asperata. The experiment was carried out from summer 2021 to 2022, where urea (CH₄N₂O) was applied to simulate nitrogen deposition. Three nitrogen deposition gradients were established with concentrations of 0 (CK), 50 (low nitrogen), and 100 kg·hm^?2a^?1 (high nitrogen). Leaf samples were collected after the last nitrogen application each year, and eight leaf functional traits (leaf area, specific leaf area, leaf dry matter content, leaf carbon content, leaf nitrogen content, leaf phosphorus content, leaf nitrogen-to-phosphorus ratio, and leaf carbon-to-nitrogen ratio) were measured and compared. Result: 1）The leaf functional traits of plants exhibited significant responses to different nitrogen addition treatments, with leaf nitrogen content, specific leaf area, and leaf phosphorus content significantly increasing under nitrogen addition, while leaf dry matter content, leaf nitrogen-to-phosphorus ratio, and leaf carbon-to-nitrogen ratio significantly decreased. There were also correlations among leaf functional traits; specific leaf area was significantly positively correlated with leaf area and leaf nitrogen content, but negatively correlated with leaf dry matter content. 2）The response of leaf functional traits to nitrogen addition varied among different tree species. For example, only the leaf area of B. platyphylla, P. koraiensis, and P. amurense showed significant responses to nitrogen addition, while other species showed no significant changes; however, all species exhibited significant responses in leaf phosphorus content to nitrogen addition.3）Different types of tree species adopted distinct survival strategies. Broadleaf species represented by B. platyphylla and J. mandshurica increased leaf nitrogen content and specific leaf area to enhance photosynthetic efficiency for rapid growth, whereas the coniferous species P. koraiensis , and P. asperata exhibited relatively slow growth while maintaining higher leaf dry matter content. Conclusion: This study demonstrates that nitrogen addition exerts differential effects on leaf functional traits across tree species. Under nitrogen enrichment, resource-acquisition-related functional traits, such as specific leaf area , were enhanced in seedlings of the region. Broadleaf species exhibited increased leaf nitrogen content and specific leaf area to improve resource acquisition, whereas conifer species adjusted leaf dry matter content to strengthen resource conservation strategies, thereby adapting to nitrogen-rich environments. These findings provide critical insights into the impacts of nitrogen deposition on forest ecosystems and offer practical guidance for forest management, such as selecting tree species with higher nitrogen-use efficiency. The results further contribute to theoretical understanding of nitrogen deposition effects on forest ecosystems and provide a scientific basis for ecological management practices addressing nitrogen deposition.

Objective: This study aims to analyze the seasonal variations and differences of ecological health factors in typical recreational forests in Beijing Xishan National Forest Park. Using the commonly applied open-field test on mice in medical research, the study explores the differences in the ecological health functions of recreational forests composed of different tree species, and investigates the impact of forest environmental health factors on the health status of mice. This research provides a scientific basis for the selection of health-promoting tree species and plant configurations. Method: Five typical recreational forests, including Platycladus orientalis pure forest, coniferous and broad-leaved mixed forest, broad-leaved mixed forests, Ginkgo biloba pure forest, and Styphnolobium japonicum pure forest, were selected as study objects. Observations and evaluations were conducted in spring, summer, autumn, and winter on environmental health factors such as climate comfort, oxygen content, air ion concentration, and PM_2.5 levels. The open-field test on animals was carried out in summer, when the comprehensive ecological health factors were optimal, to explore the ecological health effects of different recreational forests. Result: 1) Compared to the square (CK), the five types of recreational forests significantly improved human comfort, air ion concentration, oxygen content, however reduced PM_2.5 concentration throughout the year, with the highest ecological health levels observed in summer. Among them, broadleaf mixed forests and coniferous-broadleaf mixed forests showed superior ecological health functions compared to P.orientalis pure forest, G. biloba pure forest and S. japonicum pure forest. 2) The open-field test results indicated that, compared to the indoor control group, mice living in the five recreational forests for 6 days exhibited significantly increased total distance traveled, distance travelled in central area, number of times entering central area, and time spent in central area(P < 0.05). Their body weight showed a highly significant increase (P < 0.01), and the number of fecal grains was significantly reduced (P < 0.05). Among the five forests, broadleaf mixed forests and coniferous-broadleaf mixed forests provided better health effects for the mice than P. orientalis pure forest, G. biloba pure forest and S. japonicum pure forest. 3）Pearson correlation analysis revealed significant positive correlations (P < 0.05) between the spontaneous behavior and physiological indicators of mice and the human comfort, air ion concentration, and oxygen content in the recreational forests, while the correlation with PM_2.5 concentration was not significant. Conclusion: Overall, the seasonal variation patterns of ecological health factors in the typical recreational forests of Beijing Xishan Forest Park show that summer is superior to spring, autumn, and winter, and broadleaf mixed forests and coniferous-broadleaf mixed forests were better than P. orientalis pure forest, G. biloba pure forest and S. japonicum pure forest. The summer open-field test results indicated that mice in the broadleaf mixed forest and coniferous-broadleaf mixed forest showed obvious improvements in exploration, cognitive abilities, and mental state.

Objective: The central subtropical region is facing a challenge of increasing nitrogen deposition. Soil microorganisms are the link for maintaining terrestrial ecosystems and sensitive to global change. This study aims to explore the response of soil microorganisms and enzyme activities to the increased nitrogen deposition in Eucalyptus plantations in mid-subtropical region, so as to provide scientific basis for further research on the impact of nitrogen deposition on Eucalyptus plantation ecosystems under the background of global change. Method: A simulated nitrogen deposition experiment was established in Eucalyptus plantations in 2018, and four treatments were set up: CK (0 kg·hm^?2a^?1), low nitrogen (LN, 50 kg·hm^?2a^?1), medium nitrogen (MN, 100 kg·hm^?2a^?1) and high nitrogen (HN, 150 kg·hm^?2a^?1). After five years of simulated nitrogen deposition treatment, soil physical and chemical properties, microbial community structure, microbial diversity and soil enzyme activities were analyzed. Result: 1) Compared with the control, nitrogen deposition significantly increased soil cation exchange capacity, and the content of clay, soil organic carbon, total nitrogen, nitrate nitrogen, dissolved organic nitrogen, and microbial biomass nitrogen. As the level of nitrogen deposition increased, the content of total phosphorus, microbial biomass phosphorus, ammonium nitrogen and sand showed a trend of first increase and then decrease. The silt content showed a trend of first decrease and then slight increase, which was lower than that of the control. 2) Nitrogen deposition increased the total phospholipid fatty acids (PLFAs) of soil microorganisms. Low and medium nitrogen deposition treatments increased the content of soil bacteria, fungi, Gram-positive bacteria, actinomycetes, arbuscular mycorrhizal fungi and Gram-negative bacteria, and promoted the activities of soil β-glucosidase, cellulase, catalase, polyphenol oxidase, β-N-acetylglucosaminidase, urease and acid phosphatase. However, all the parameters tended to decrease under high nitrogen deposition. 3) The results of correlation and redundancy analysis showed that soil cation exchange capacity, microbial biomass nitrogen, silt, total nitrogen, dissolved organic nitrogen and total phosphorus contents were the key environmental factors affecting the changes of microbial community structure and soil enzyme activities. Conclusion: The short-term simulated nitrogen deposition of five years has improved the soil physico-chemical properties in Eucalyptus plantations, changed the soil microbial community structure and increased soil enzyme activities. Low and medium nitrogen deposition levels have a promoting effect on soil physicochemical properties, microbial community structure and soil enzyme activities, while high nitrogen deposition shows a certain inhibitory effect.

Objective: This study aimed to analyze the endophytic fungal communities and diversity in the roots of Rhododendron moulmainense with varying growth potential in Wutong Mountain, Shenzhen, China. The goal was to identify representative endophytic fungi with potential benefits for plant growth and lay a foundation for utilizing these fungal resources. Method: Root samples from R. moulmainense with different growth potential were analyzed using amplicon ITS high-throughput sequencing and tissue isolation cultivation to characterize fungal taxa and diversity. Result: 1) Amplicon ITS high throughput sequencing of root associated fungi in R. moulmainense revealed distinct community profiles between good and poor growth potential samples. For good growth potential roots, 183 942 sequences were annotated into 11 phyla, 231 fungal species, and 778 operational taxonomic units (OTUs). In contrast, poor growth potential roots yielded 190 918 sequences, annotated into 10 phyla, 202 fungal species, and 1 009 OTUs. Despite differences in taxonomic richness, Basidiomycota and Ascomycota emerged as the dominant phyla across both growth potential groups. 2) Alpha diversity analysis revealed that the fungal communities in the roots of R. moulmainense with good growth potential exhibited greater diversity compared to those with poor growth potential. Principal Coordinate Analysis (PCoA) further demonstrated that communities sharing the same growth potential clustered closely, indicating high similarity, whereas communities from differing growth potential levels showed divergence. 3) Functional prediction analysis demonstrated that in the fungal communities associated with the roots of good growth potential R. moulmainense, symbiotrophic fungi accounted for nearly 60% of the total community. In contrast, fungal communities from poor growth potential roots exhibited a balanced distribution, with both saprotrophic fungi and symbiotrophic fungi each comprising approximately 40%. 4) Through tissue isolation and cultivation methods, a total of 172 endophytic fungal species were identified in the roots of R. moulmainense. Ascomycota dominated the fungal communities in both good and poor growth potential plants. Specifically, 98 fungal species were identified in good growth potential roots, while 109 species were found in poor growth potential roots. Among these, 12 representative fungal strains were isolated from good growth potential plants, compared to 6 strains from poor growth potential plants. Notably, typical Ericoid mycorrhizal fungi, including Oidiodendron and Pezicula ericae, were exclusively isolated from good growth potential roots. Conclusion: Amplicon ITS high-throughput sequencing and tissue isolation techniques revealed significant differences in the diversity of endophytic fungal communities within the roots of R. moulmainense exhibiting different growth potential. Compared to plants with poor growth potential, those with robust growth demonstrated a higher abundance of endophytic fungi, particularly dominated by taxa such as Oidiodendron and P. ericae, which were both more diverse and numerically prevalent. This discovery underscores a potential link between the root-associated mycobiome ecology of R. moulmainense and its growth performance, providing novel perspectives for further exploration of plant-microbe interactions and their role in enhancing plant resilience and vitality.

Objective: The aim of this study was to develop a carbon storage growth graded model system incorporating carbon sequestration grade, stand density index, and stand age, and put forward a method for estimating carbon sequestration potentiality, which can be used to assess the carbon sequestration potentiality at forest management unit scale, thereby providing a basis for forest management to increase carbon sequestration. Method: Based on the data of permanent sample plots of Pinus tabuliformis pure forest of Shanxi Province and theoretical growth model, a double iterative grading algorithm was used to ascertain the carbon sequestration grade and to develop the carbon storage graded growth model system. This model system includes mean individual tree carbon storage graded, stand carbon storage graded, mean individual tree basal area graded and stand basal area graded growth models. Models were evaluated by the coefficient of determination (R²), root mean square error and relative root mean square error. The optimization method was applied to determine the optimal stand density that maximizes carbon sequestration potentiality, with the maximum stand carbon storage annual increment as the objective function and stand density as the decision variable. The realized carbon sequestration, potential carbon sequestration, and the gap between them were analyzed based on the sub-compartment survey data from Zhongtiaoshan Bureau of Shanxi Province. Result: The R² values were 0.920 and 0.903 for mean individual tree carbon storage graded growth model and basal area graded growth model respectively, and 0.966 and 0.985 for stand carbon storage graded growth model and basal area graded growth model, respectively, indicating a good fit for all growth models. Stand carbon sequestration potentiality increases initially and then decreases with stand age, and it rises with an increase of carbon sequestration grade. The average potential and realized carbon sequestration for P. tabuliformis pure forests was 1.59 and 0.97 t·hm^?2a^?1 at unit area, respectively, with an average relative carbon sequestration growth gap was 29.08% in Zhongtiaoshan Bureau. Conclusion: This study successfully established a carbon storage graded growth model system for P. tabuliformis pure foresr that can predict carbon storage growth process. It is recommended to make stand density adjustment for P. tabuliformis plantations to increase realized carbon sequestration. This approach can serve as a reference for carbon management aimed at increasing carbon sequestration in both P. tabuliformis forests and other forest types.

Objective: Long-term irrigation and nitrogen application can cause a waste of water resources and soil acidification, leading to ecological security problems. This study aims to clarify the optimal irrigation and fertilization strategy for the late stage of Populus tomentosa pulpwood cultivation, so as to provide a basis for water and fertilizer management in different periods of short-rotation P. tomentosa pulpwood and also provide reference for solving problems such as water resource waste and soil acidification caused by long-term irrigation and nitrogen application. Method: The triploid P. tomentosa in the sandy land of the North China Plain was taken as the research subject, and an augmented experimental design was employed to conduct a drip irrigation water-nitrogen coupling experiment. Three irrigation treatments (W20, W33, W45) and four nitrogen application levels (N0, NL, NM, NH) were set up to investigate the spatiotemporal dynamics of the leaf area index (LAI) and soil volumetric water content (SVWC) under different water-nitrogen treatments during the fifth growing season (April to October), as well as the tree growth and soil nutrient characteristics at the end of the growing season. Result: 1) At the end of the cultivation of P. tomentosa pulp wood, after 4 years of drip irrigation water and nitrogen coupling, there was no significant difference in forest growth, forest stock and forest productivity under different water and nitrogen conditions. 2) The water-nitrogen coupling of drip irrigation did not change the changing trend of LAI throughout the growing season. However, due to the impact of the wind disaster (occurred on June 1), LAI showed a bimodal pattern, reaching peaks around May 30 and July 15. 3) In spring (May), the W20 irrigation treatment (when the soil water potential was –20 kPa) mainly increased the moisture in the root zone soil surface (0?50 cm), while the W33 and W45 irrigation treatments (when the soil water potential was –33 kPa and –45 kPa) mainly increased soil moisture at 100?180 cm. In summer (July), irrigation was able to increase 0?180 cm depth SVWC. The W20 supplemented soil moisture better than the W33 and W45 treatments. After irrigation was stopped in autumn (October), the deep soil moisture was replenished under W20 and W33 treatments, while the surface soil in autumn became drier than that in spring and summer. 4) Soil nutrients in P. tomentosa forestland mainly accumulated in the shallow soil layer (0?40 cm). The response of soil organic matter and total nitrogen content in the shallow soil layer to water-nitrogen coupling was weaker than that of available phosphorus. Among them, irrigation had greater effect on the accumulation of available phosphorus than fertilization. And under sufficient water conditions (W20 and W33 irrigation), the increase in nitrogen application inhibited the accumulation of soil phosphorus content. 5）There was a significant positive correlation between soil available phosphorus content and tree diameter at breast height. Thus, drip irrigation water-nitrogen coupling measures can regulate soil phosphorus content and affect the growth of forest trees. Conclusion: Water-nitrogen coupling for 4 consecutive years has no significant promotion effect on tree growth and forest productivity at the late stage of the cultivation of P. tomentosa pulpwood. Moreover, under the levels of heavy irrigation (W20 and W33), high-level nitrogen fertilization (NM and NH) may reduce the soil available phosphorus accumulation and inhibit forest growth. Comprehensive consideration of economic costs and ecological security, it is recommended that under similar site conditions, fertilization should be stopped in the fifth year of short-rotation P. tomentosa pulp cultivation and sufficient irrigation should be maintained (irrigation threshold is ?20 kPa), so that soil moisture and nutrients can be maintained at a higher level to achieve sustainable soil fertility.

Objective: The aim of this study was to investigate the physiological characteristics of persimmon (Diospyros kaki) in the rooting process of softwood cutting, and to explore the dynamic changes and effects of endogenous hormones, oxidase activity and endogenous rooting inhibitor content, so as to provide technical and theoretical support for further study on the development mechanism of adventitious roots in persimmon softwood cutting and rapid propagation of excellent rootstock resources. Method: The semi-lignified twigs cut from 5-year-old grafted ‘Zhongshi 7’ persimmon seedling were used as experimental materials, and the cutting base was treated with special rooting agent for 30 s, and the rooting rate of cuttings was calculated in 35 days after cutting. The high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used to determine the contents of auxin (IAA), abscisic acid (ABA), gibberellin (GA₃) and zeatin (ZR). The colorimetry was used to determine the activities of indoleacetic acid oxidase (IAAO), polyphenol oxidase (PPO), superoxide dismutase (SOD) and oxidoreductase (POD) and the contents of total phenols (TP), total flavonoids (TF) and total tannins (TT). Result: 1) The rooting process of persimmon softwood cutting was able to be divided into root primordium induction period (0–15 days), adventitious root expression period (15–25 days) and adventitious root elongation period (25–35 days). At the adventitious root expression stage, young white adventitious roots were able to be observed breaking through the cortex at the base of the cuttings. The rooting type of persimmon shoot cuttings was dominated by bark-derived rooting and mixed rooting, and the rooting rate of persimmon shoot cuttings was able to reach up to 82.33%, with an average root length of 6.54 cm, and an average number of roots per cutting up to 6.80 roots. 2) The endogenous hormone contents of persimmon shoot cuttings changed with the rooting process, in which the contents of IAA and ZR increased gradually, and the content of ABA increased first and then decreased, and reached the maximum at 20 days, while the content of GA₃ decreased gradually. IAA, GA₃, ABA and ZR played different roles in root primordium induction and adventitious root formation. 3) The rooting of persimmon cuttings was closely related to the activity of oxidase. Among them, the activities of SOD and PPO were stable at first and then decreased, and the activities of SOD and PPO maintained high for 15 days until the root primordium induction period when they significantly decreased. The POD activity increased at first and then decreased, and reached the maximum in 20 days of cutting. The IAAO activity decreased gradually, and at the same time the IAA content increased. 4) The rooting of persimmon softwood cuttings was closely related to endogenous rooting inhibitors, and the contents of total phenols, total flavonoids and total tannins decreased first and then increased slightly, reaching the lowest value in 25 days of cutting, but slightly increasing in 35 days of cutting. Conclusion: During the rooting process of persimmon softwood cuttings, the increase of IAA content and the decrease of endogenous rooting inhibitors such as total phenols, total flavonoids and total tannins are the key factors for inducing adventitious root formation. At the same time, the increase of ZR content, the decrease of GA₃ and ABA content, and the decrease of IAAO activity are closely related to the rooting.

Objective: With the mangrove plant Kandelia obovata as the test material, this study investigated the mechanism by which nano zinc oxide (ZnO NPs) enhances the cold resistance of K. obovata seedlings, providing crucial technical support for the safe overwintering of mangroves on the northern margin or in higher latitudes. Method: K. obovata seedlings were pre-treated with foliar spraying method with varying concentrations of ZnO NPs to determine the optimal application concentration. Seedlings were then sprayed with optimal concentration of ZnO NPs twice daily in the morning and evening for 3 days, followed by exposure to low-temperature stress at 8 ℃ (day)/–3 ℃ (night) for 3 days. Physiological indices such as photosynthetic rate, antioxidant enzyme activity, and melatonin (MEL) synthesis pathway were measured. Result: The leaf net photosynthetic rate (P_n) and melatonin (MEL) content of seedlings initially increased and then decreased with increasing ZnO NP concentration, with 200 mg·L^?1 being the optimal concentration under low-temperature stress. Low-temperature stress significantly decreased endogenous MEL and nitric oxide (NO) contents and increased contents of superoxide anion (${\mathrm{O}}_2^{\overline{\;\cdot\; }} $) and hydrogen peroxide (H₂O₂), thereby inhibiting photosynthesis. Spraying treatment with 200 mg·L^?1 ZnO NPs on leaves was able to effectively increase the activities of N-acetylserotonin methyltransferase (ASMT) and tryptophan decarboxylase (TDC) in the MEL synthesis pathway of K. obovata seedlings under low temperature stress, and promote the production of various intermediate products (tryptamine, 5-hydroxytryptamine, and 5-methoxytryptamine) in the synthesis process of melatonin from tryptophan. Additionally, ZnO NPs not only effectively increased antioxidant enzyme activities, reduced ${\mathrm{O}}_2^{\overline{\;\cdot\; }} $ and H₂O₂ contents, but also activated nitrate reductase (NR) activity by H₂O₂ in the leaves under low temperature stress, promoting NO₂^? production, and ultimately improving photosynthesis, which is closely related to the melatonin synthesis pathway. Conclusion: ZnO NPs enhances the cold resistance of K. obovata seedlings by regulating the MEL/ROS/ reactive nitrogen species (RNS) redox network under low-temperature stress. ZnO NPs may induce the tryptophan/tryptamine/5-hydroxytryptamine/5-methoxytryptamine/melatonin synthesis pathway in K. obovata seedlings under low-temperature stress, influencing the redox network formed by melatonin, ROS, and RNS.

Objective: This study aims to investigate the effect of witches’ broom disease on the hydraulic architechture and carbon metabolism of jujube trees to reveal the pathophysiological mechanism of witches’ broom disease, so as to provide a theoretical basis for the formulation of targeted management measures. Method: The healthy, mild diseased and severe diseased Ziziphus jujuba cv. ‘Huping’ trees were used as the research object. The maximum hydraulic conductivity (K_max), hydraulic vulnerability to embolism (P₅₀), and morphological and anatomical characteristics of the jujube branches and leaves were measured. The water potential, branch percentage loss of conductivity (PLC), gas exchange parameters and nonstructural carbohydrates (NSC) contents of the three types of jujube trees in winter-spring period (November to April of the following year) and growing season (June) were also compared. Result: With the aggravation of the disease, the K_max of the jujube branches and leaves significantly decreased, and the P₅₀ of the branches and leaves significantly increased. The branch K_max of mild and severe diseased jujube trees was reduced by 40.75% and 80.61%, and the leaf K_max of mild and severe diseased jujube trees was reduced by 12.25% and 29.44%, respectively, compared to that of healthy jujube trees. The branch P₅₀ of mild and severe diseased jujube trees increased by 0.18 MPa and 0.63 MPa, and the leaf P₅₀ of mild and severe diseased jujube trees increased by 0.15 MPa and 0.31 MPa, respectively, compared to that of healthy jujube trees. With the aggravation of the disease, the thickness of vessel wall and collapse resistance index of the branches decreased significantly, and the wood density and vessel diameter of the branches of the severe diseased trees were significantly lower than those of the healthy ones. During winter-spring period and growing season, with the aggravation of the disease, branch PLC increased significantly, and phloem water content, phloem cell viability, and NSC content in phloem and xylem of branches decreased significantly. The photosynthetic rate, stomatal conductance and transpiration rate of leaves decreased significantly in the growing season, with photosynthetic rate of leaves of mild and severe diseased jujube trees being reduced by 12.25% and 29.44% compared to that of healthy jujube trees, respectively. Conclusion: The decrease in maximum hydraulic conductivity of leaves and branches is mainly related to the decrease of vessel diameter, and the decrease in hydraulic safety is mainly related to the decrease of vessel wall thickness, vessel collapse resistance and wood density, which may be caused by insufficient carbon supply. The decrease in water transport capacity and safety affects the water status of trees in the winter-spring period and growing seasons, limiting photosynthesis and resulting in carbon limitation, which further constrains the growth and the adaptability of jujube trees to adversity. Hydraulic limitation and carbon limitation are an important reason for the poor growth and dieback of diseased jujube trees.

Objective: In this study, the differences in key indicators of starch and sucrose metabolism in the leaves of Populus deltoides parents and their F1 hybrids with different growth potentials were investigated at different forest ages during critical periods of annual growth, with which the role of starch and sucrose metabolism in the formation and maintenance of growth heterosis in P. deltoides was analyzed. This study aims to provide valuable references for revealing the role of starch and sucrose metabolism in the formation and maintenance of growth heterosis in trees, as well as in high-yield hybrid breeding of poplars. Method: With the space-for-time substitution method, the high-growth potential hybrids (H1, H2, H3) and low-growth potential hybrids (L3, L4) at 1- and 3-year-old forest, along with their male (MP) and female (FP) parents of P. deltoides were selected as the research materials. The content of starch and sucrose, as well as the activities of ADP-glucose pyrophosphorylase (AGPase), sucrose phosphate synthase (SPS), β-amylase (BAM), and sucrose synthase (decomposition direction, SS-I) in the leaves at different time points during critical growth periods (July, August, September) were measured using micro-methods. The differences in various indicators were compared among hybrids and parents, and the correlation and regression, as well as path analysis were conducted to elucidate the regulatory patterns of key indicators in starch and sucrose metabolism in the formation of different growth potentials. Result: During the critical growth periods, high-growth potential hybrids at 1-year-old and 3-year-old forest exhibited significant high-parent heterosis (HPH) in growth traits such as tree height and diameter at breast height (DBH), and showed obvious mid-parent or high-parent heterosis in key indicators of starch and sucrose metabolism. However, the sugar metabolism characteristics that promote and maintain growth heterosis in high-growth potential hybrids of P. deltoides were different with different ages. Among them, 1-year-old high-growth potential hybrids showed high-parent heterosis in the activity of daytime starch and sucrose synthesis related enzymes (AGPase and SPS), as well as nighttime starch consumption, with HPH values of 1.63%–13.47%, 5.41%–16.03%, 0.58%–4.44%, respectively. Moreover, AGPase and SPS activities were significantly positively correlated with the net increase of tree height and ground diameter (GD), with significantly positive direct effects (P< 0.05). Except for daytime SPS activity and nighttime sucrose consumption, which showed high-parent heterosis (HPH: 0.61%–14.77%, 0.29%–26.05%), the 3-year-old high-growth potential hybrids showed mid-parent heterosis (MPH) in other sugar metabolism indicators, which were 0.42%–12.23%, 0.25%–12.20%, 0.76%–5.20%, respectively. There were significant correlations between key sugar metabolism indicators and growth traits of 3-year-old P. deltoides, which were influenced by the month of measurement. The nighttime sucrose consumption and BAM, SPS, and AGPase activity had a decisive role on net growth in July, August, and September, respectively. These indicators showed opposite trends in low-growth potential hybrids. Conclusion: The heterosis phenomenon in growth traits of P. deltoides is stable at both 1-year-old and 3-year-old forest, and the characteristics of sugar metabolism-related indicators during critical growth periods are closely related to the formation and maintenance of growth heterosis. The sugar metabolism strategies for maintaining growth heterosis in high-growth potential hybrids of P. deltoides with different forest ages are different. For 1-year-old forest, growth heterosis is primarily enhanced by increasing the accumulation and transport of sucrose and starch during day and night. The 3-year-old high-growth potential hybrids maintain their growth heterosis mainly through the accumulation and transport of sucrose, with this process being influenced by the month of measurement.

Objective: Phoebe bournei is well adapted in red soils with low available phosphorus. Purple acid phosphatases (PAPs) are important acid phosphatases that hydrolyse a wide range of substrates in response to low phosphorus stress to release soluble inorganic phosphorus. This study aims to identify PAPs genes in response to low phosphorus stress and verify the functions in order to explore the response mechanism of P. bournei under low phosphorus stress, which will provide a theoretical basis for cultivating germplasm with efficient phosphorus utilization in P. bournei. Method: Based on the genome data of P. bournei, the PAPs gene family was identified by blastp homology and hmmersearch, and the protein sequences of PbPAPs were compared with those of Arabidopsis thaliana and Picea abies to construct a phylogenetic tree. The photosynthetic fluorescence parameters, inorganic phosphorus content, acid phosphatase (ACP) activity and the expression levels of PbPAPs under different phosphorus contents (0 mmol·L^?1 KH₂PO₄ and 1 mmol·L^?1 KH₂PO₄) in two P. bournei families (Jing'an No.3 and Yifeng No.5) were analyzed, and then three PbPAPs were screened out for the subsequent functional study. Result: A total of 22 PbPAPs genes were identified, all contained Metallophos domains, and were unevenly distributed on 10 chromosomes of P. bournei, with amino acid lengths ranging from 326 to 648 aa. Most of PbPAPs proteins had isoelectric points less than 7, and the exons number ranged from 2 to 13. These PbPAPs harbored two pairs of tandem duplications and four pairs of segmental duplications, and the phylogenetic tree was divided into 3 groups. Under low phosphorus treatments, the elongation of the primary root was inhibited, while the root hair density and the surface area of the root system were increased in the seedlings of P. bournei two families. The net photosynthetic rate and F_v/F_m value were decreased significantly, while the acid phosphatase activity increased. The inorganic phosphorus content of Jing'an No.3 leaves firstly declined and then increased slightly, while the change in Yifeng No.5 was relatively stable. A significant decrease of Pi content was observed in the Jing'an No.3 root after 7 days of treatment, while a significant decrease was firstly observed in the Yifeng No.5 after 21 days of treatment, and the change trends in the later stage of treatments were similar. According to RT-qPCR analysis, low phosphorus induced the gene expression level of PbPAP10a, PbPAP15a and PbPAP26. The three genes of PbPAP10a, PbPAP15a and PbPAP26 were overexpressed in P. bournei roots and A. thaliana by Agrobacterium tumefaciens- and A. rhizocarcinosum-mediated genetic transformation, which resulted in a significant enhancement of ACP activity and a significant increase in Pi content. Thus, overexpression of the PbPAPs gene increased ACP activity and Pi content. Conclusion: It is shown that P. bournei has high tolerance to low phosphorus stress, and Yifeng No.5 is more tolerant to low phosphorus stress than that of Jing'an No.3, which is suitable for forestation in barren forest land or acidic low phosphorus forest land. Overexpression of PbPAPs gene increases ACP activity and Pi content, which would help P. bournei to adapt to the low phosphorus environments.

Objective: Paracarophenax alternatus is a newly identified parasitic mite exhibiting parasitic efficacy against Monochamus alternatus eggs. This study aims to investigate the effects of environmental factors on the parasitism efficiency of P. alternatus, to evaluate its potential in biological control programs, to optimize artificial rearing systems, and to refine field application strategies. Method: An indoor feeding experiment under controlled laboratory conditions was conducted to assess the impacts of M. alternatus egg age (0–4 days post-oviposition), mite-to-egg ratios (1∶1–8∶1), temperature (17–33 ℃), relative humidity (RH: 60%–95%), and photoperiod (24L, 12L∶12D, 24D) on the parasitism rates of P. alternatus. A predictive model was developed using random forest regression analysis to quantify parasitism rates under varying environmental conditions. Result: 1） Under the conditions (mite-to-egg ratio 5∶1, 25°C, 85% RH, 12L∶12D), the parasitism rate of P. alternatus on newly laid eggs of M. alternatus was the highest, reaching 74.44%, significantly exceeded the parasitism rate of 44.44% on 4-day-old eggs of M. alternatus P<0.05), demonstrating that as the age of M. alternatus eggs increases, the parasitism rate significantly decreases. 2） Under the conditions (5∶1 mite-to-egg ratio, 25 ℃, and 12L∶12D), the parasitism rates of P. alternatus reached 93.33% and 88.00% at 95% and 90% RH, respectively, and were significantly higher than that of 30.00% at 60% RH (P<0.05). 3） Under the conditions (4∶1 mite-to-egg ratio and 85% RH), the parasitism rates of P. alternatus on the eggs of M. alternatu were 75%, 78.8%, and 83.3% at temperatures of 21 ℃, 25 ℃, and 29 ℃, respectively, and significantly (P<0.05) higher than those of 10% and 21.7% at 17 ℃ and 33 ℃. 4） Under the conditions (29°C, 85% RH, 12L∶12D, mite-to-egg ratios of 4∶1–8∶1), the parasitism rates of P. alternatus were 88.3%, 83.30%, and 86.7% at the mite egg ratios of 4:1, 6:1, and 8:1, respectively, and significantly higher than those of 41.70% and 36.67% at the mite egg ratios of 1∶1 and 2∶1 (P<0.05). 5） Under the conditions (mite egg ratio of 5:1, 25 ℃, and RH 85%, 24 D, 12 L: 12 D, and 24 L), the parasitism rates of P. alternatus at continuous darkness (24D) achieved the highest parasitism rate (92.50%), outperforming 12L∶12D (73.75%) and 24L (68.75%, P<0.05). 6） The random forest regression model exhibited robust accuracy (MSE = 100.68, R² = 0.83), and predicted the maximum parasitism rates (>90%) under conditions of freshly laid eggs, 5∶1 mite-to-egg ratio, 20–31 ℃, RH >93%, and 24D photoperiod. Conclusion: Egg age, temperature, humidity, photoperiod, and mite-to-egg ratio significantly influence the parasitism efficiency of P. alternatus on the eggs of M. alternatu. For optimal biological control or mass rearing, conditions should include mite-to-egg ratios ≥5∶1, temperatures of 21–29 ℃, RH ≥90%, and complete darkness. These findings provide critical insights for optimizing mass-rearing protocols and field deployment strategies to enhance the efficacy of P. alternatus in suppressing M. alternatus populations.

Objective: This study aims to explore the genetic diversity, genetic differentiation, and phylogenetic relationships of Paratrioza sinica populations in northwest China, so as to provide molecular biological theoretical basis for the regional occurrence patterns of P. sinica and the formulation of prevention and control strategies. Method: In this study, 512 samples of P. sinica were collected from 18 different geographical populations in northwest China from June to August 2023. The mtDNA COI gene was amplified with PCR and sequenced, and the mtDNA COI gene sequence variation, phylogenetic and genetic differentiation were analyzed by using MEGA7.0, Dna SP 5.0, Arlequin 3.5, and Network 10.0 software. Result: 1) The length of the amplified fragment was 474 bp, and the content of the base T, C, A, and G was 35.6%, 22.2%, 26.8%, and 15.4%, respectively. The A+T content (62.4%) was significantly higher than the G+C content (37.6%), showing a significant base bias. The nucleotide diversity was 0.002 5, and the average nucleotide difference number of k was 1.110. 2) There were 5 haplotypes detected, with the haplotype diversity of 0.512. Among them, haplotype H2 was the dominant haplotype, and appeared 344 times, accounting for 67.19% of all detected individuals. 3) The Taijima's D and Fu's Fs values of the 18 P. sinica geographic populations were 0.876 and 0.911, respectively, and both of them did not reach significant levels. 4) The population genetic differentiation index was 0.642 78, and the gene flow was 0.21. The percentage of genetic variation within populations was 35.72%, and the percentage of genetic variation between populations was 64.28%. The variation within populations was significantly smaller than that between populations (P<0.01). 5) The haplotype NJ phylogenetic tree and network mediation diagram showed that the five haplotypes were clearly clustered into 4 clusters. 6) The genetic distance among various populations ranged from 0.000 to 0.007. The UPGMA clustering results indicated that the populations from Delingha (DLH) and Golmud (GEM), as well as those from Gulang County (GLX) and Shihezi (SHZ) were significantly differentiated compared to other populations. 7) The Mantel test showed that there was a significant moderate positive correlation (r=0.675, P<0.05) between genetic distance and geographic distance among the 18 geographical populations of P. sinica. Conclusion: The 18 geographical populations of P. sinica in the northwest region exhibit low genetic diversity, with genetic variation occurring both among and within populations. The main factor contributing to the overall population variation is interpopulation variation, while intrapopulation genetic differentiation is relatively low.

Objective: In this study, the satellite tracking data of Oriental stork was used to analyze the effects of different breeding populations, tracker models, attachment methods and device weights on the working time of the satellite trackers and survive probability of the birds, which aimed to provide basic information for the design and attachment of satellite trackers for large waterbirds such as storks and cranes in the future. Method: From 2014 to 2022, satellite trackers were attached on 149 fledgling Oriental storks in the Sanjiang Plain, the Songnen Plain and the Yellow River Delta in Shandong Province. The weight of the tracker was 0.76% ± 0.23% of the weight of the corresponding tracked juvenile bird, and it did not exceed 3% of the weight of the tracked individual. Survival analysis which specifically targeted at time-to-events data was used to explore the effects of different factors on juvenile mortality and device failure. Result: The larger the proportion of tracker weight to bird weight, the higher the individual's risk of death. With technological advancements, the annual failure rate of the new device reduced by 27% compared to the previous year. Factors such as different populations and attaching styles had no significant impact on the survival probability and equipment failure rate of juvenile birds. Conclusion: Priority should be given to trackers that have the least impact on animal behavior, and the satellite tracker should be developed towards a smaller volume and weight, a longer service life, and the ability to detach at regular intervals.

Objective: The present study utilized an artificial neural network model to forecast the moisture content variation during the drying process of phenolic resin impregnated heat-treated bamboo bundles (PHB), elucidating the impact of drying temperature, drying time, paving method, and initial moisture content on the moisture variation during the drying process. The findings provide a fundamental reference for achieving high-quality and efficient drying of PHB. Method: The measured data of moisture content during the drying process of PHB samples was utilized to create a dataset, with input variables including drying temperature, drying time, paving method, and initial moisture content. The output variable was the moisture content during the drying process. Subsequently, this dataset was divided into three sets: the training set, consisting of 308 data points (70% of the total data); the validation set, comprising 66 data points (15% of the total data); and the test set, containing 66 data points (15% of the total data). The particle swarm optimization (PSO) algorithm was employed to optimize the initial weights and thresholds of back propagation ropagation (BP) neural network, thereby constructing a PSO-BP neural network prediction model. This model has been verified and analyzed. Result: The PSO-BP neural network model exhibited robust predictive capabilities. In the test set, it achieved a coefficient of determination (R²) of 0.98, a mean square error (MSE) of 1.27, a mean absolute error (MAE) of 3.73, and a residual predictive deviation (RPD) of 7.96. Compared to the BP neural network, the PSO-BP neural network demonstrated an improvement in R² and RPD by 6.53% and 110.2%, respectively, while reducing MSE and MAE by 54.0% and 71.86%. The model verification demonstrated that the moisture content variation during the drying process of PHB was primarily influenced by the drying temperature and paving method. Both factors have a significant impact on the predictive accuracy of the PSO-BP neural network model. Optimal prediction performance was achieved when using a drying temperature of 60 ℃, regardless of the four different paving methods employed, resulting in R² values exceeding 0.969 and MSE staying below 3. Employing three layers of paving yielded superior outcomes under various drying temperature conditions, with R² values surpassing 0.99 and MSE remaining below 2. Additionally, neither drying time nor initial moisture content significantly affected the predictive accuracy of the model. Conclusion: The PSO-BP neural network model exhibited remarkable accuracy in predicting the moisture content during the drying process of PHB samples. It effectively addresses issues such as significant prediction errors and slow convergence rates that are commonly encountered with traditional BP neural networks, thereby providing valuable technical support for the high-quality and efficient drying of PHB.

Objective: To solve the problems of large measurement error, cumbersome operation, and difficult online detection in traditional contact roughness meters for measuring wood sanding surface roughness, this paper proposed a visual detection method based on local autocorrelation function entropy (LAEnt). Method: Firstly, the mechanism of detecting surface roughness using LAEnt was studied, and a local autocorrelation function entropy algorithm was established; Then, the orthogonal experimental method was used for wood sanding experiments to obtain sanding surface images and surface roughness values; Finally, the influence of factors such as the mesh number of sanding belts, sanding belt speed, and air drum feed rate on the surface roughness of wood sanding was studied. The correlation between LAEnt or autocorrelation function entropy (AEnt) and surface roughness was analyzed. Based on the local autocorrelation function entropy and autocorrelation function entropy data of the sanding surface images, support vector machine (SVM) was used to establish wood sanding surface roughness detection models SVM-LAEnt and SVM-AEnt, respectively. Result: The granularity of the sanding belt has the most significant impact on the surface roughness of wood sanding. There is a strong negative correlation between the granularity and the surface roughness. In contrast, the effects of belt speed and air drum feed rate on surface roughness are relatively minor. The local autocorrelation function entropy (LAEnt) shows a significant linear correlation with the surface roughness of wood sanding, with a correlation coefficient of 0.973 3. Furthermore, the feature extraction efficiency of LAEnt significantly outperforms that of AEnt (autocorrelation function entropy), with the per-image computational time reduced to 2.95% of AEnt’s processing time. SVM-based modeling results demonstrate that the SVM-LAEnt model achieves an average relative fitting error of 2.56% (maximum: 11.22%) and an average relative prediction error of 5.13% (maximum: 11.30%), both of which are superior to the SVM-AEnt model’s performance (average fitting error: 8.98%, maximum: 20.68%; average prediction error: 15.08%, maximum: 31.13%). Conclusion: The local autocorrelation function can describe the texture features and roughness of the wood sanding surface. When detecting the surface roughness, the local autocorrelation function entropy can better characterize the surface roughness. The results of this paper provide an efficient and accurate non-contact detection method for wood sanding surface roughness measurement.

Objective: This article aims to provide scientific evidence for optimizing state-owned forest management policies and promoting high-quality forestry development by studying the impact mechanism of the transformation of the state-owned forest management system on the development of new forestry productivity. Method: Based on panel data from 87 state-owned forestry enterprises in northeast China’s state-owned forest areas from 2010 to 2021, this study employs the entropy method to measure the level of new forestry productivity. The study uses a multi-period difference-in-differences model (multi-period DID), propensity score matching-difference-in-differences model (PSM-DID), and mediation effect model to quantitatively analyze the impact and mechanism of the transformation of state-owned forest management system on the development of new forestry productivity. Result: 1) From 2010 to 2021, the new forestry productivity index in northeast China’s state-owned forest areas increased from 0.055 8 to 0.098 7, maintaining a general upward trend. 2) The transformation of the state-owned forest management system has a significant positive impact on the development of new forestry productivity. 3) There is significant heterogeneity in the reform effects among different forestry groups. The transformation of the state-owned forest management system shows a significant positive impact on the new forestry productivity in Inner Mongolia forestry group and Daxing’anling forestry group, while in Yichun forestry group, the impact is significantly negative due to management system changes. 4) Mechanism tests indicate that environmental information disclosure and resource optimization and efficiency improvement are the main pathways through which the system transformation promotes the development of new forestry productivity. Conclusion: To further enhance new forestry productivity, it is essential to deepen management system reform, formulate differentiated policies, strengthen the environmental information disclosure system, promote resource optimization and efficiency improvement, and provide strong policy support and complementary mechanisms.

With the gradual expansion of the scale of Lycium barbarum cultivation as well as labor costs continue to increase, the realization of mechanization and intelligent harvesting of Lycium barbarum has become an important means to enhance the efficiency of Lycium barbarum production, but also to promote the quality of the Lycium barbarum industry, an effective way to develop. Based on the literature analysis method, this study combs and reviews the research progress of theory and equipment related to Lycium barbarum harvesting at home and abroad in the past 10 years, and further explores the future research direction and development trend of the existing research by analyzing the strengths and weaknesses of the existing research in theory and practical application. At present, the research on harvesting of Lycium barbarum is dominated by relevant domestic agricultural and forestry colleges and universities, and mostly take Ningxia region Lycium barbarum varieties as the object of research, the harvesting equipment is divided into portable and self-propelled, and its working mode includes vibration type, comb and brush type, pneumatic type and shear type, and the vibration type of harvesting efficiency is relatively ideal. In order to further realize the goal of efficient and low-loss harvesting of Lycium barbarum, the future research direction of Lycium barbarum harvesting related technology is proposed: 1) Combined with the differences in biomechanical properties of Lycium barbarum, strengthen the basic theoretical research, reveal the coupling and interactions mechanism between various parts in the harvesting process, and avoid the damage to the fruits in the process of mechanical operation. 2) Research and development of new agronomic techniques suitable for the operation of Lycium barbarum harvesting equipment, the deep integration of agricultural machinery and agronomy, to improve the overall harvesting efficiency. 3) Carry out the research of rapid identification and localization algorithm in complex field environment for Lycium barbarum fruit in irregular movement state, and identify and detect the maturity of Lycium barbarum fruit based on graph fusion technology. 4) Development of large-scale Lycium barbarum harvesting equipment based on automatic navigation technology and intelligent obstacle avoidance system.