To explore the phenotypic adaptability and resistance mechanism of different Schima superba families after snow disaster, and to provide a theoretical basis for breeding and disaster resistance improvement of S. superba.

Taking 24 S. superba families affected by snow disaster as the research object, 13 phenotypes such as DBH, tree height and crown width and forest damage indexes were measured. The correlation between phenotypic characteristics and disaster resistance of families was comprehensively evaluated by variance analysis, correlation analysis, cluster analysis and principal component analysis.

1) Different families of S. superba showed significant differences in growth traits and crown shape characteristics. The DBH of LQ15, XF02, JO30, JO58 and QY10 families was much higher than the average value of 5.47 cm, showing fast-growing potential. The YX01 family enhanced the survival rate with low tree height (2.8 m). The branch height and natural pruning ability of LX02 and HA02 families were outstanding; 2) The JO16 family improved resource utilization efficiency through canopy expansion, while the YX01 family adopted a strategy of inhibiting canopy expansion to adapt to the rain and snow disaster environment; 3) There were significant differences in the sensitivity of S. superba families to rain and snow disasters. The YX01 family had the highest damage rate and its resistance to mechanical damage was weak, while the LX02 and JO16 families showed strong resistance to snow disasters and were not significantly damaged; 4) Growth traits were significantly correlated with disaster resistance. DBH and tree height were negatively correlated with damage rate, average damage level and damage index (P<0.05). The proportion of branch height, crown volume and crown height were significantly positively correlated with the damage degree of S. superba, reflecting their vulnerability under high stress environment; 5) Principal component analysis (cumulative contribution rate of 92.735%) showed that LX02, JO16, LQ01, JO5 and XF02 families performed best in phenotypic characteristics.

The LX02, JO16, LQ01, JO5 and XF02 families have both growth potential and disaster resistance adaptability, and can be used as priority breeding materials. The YX01 family is not suitable as a breeding material. In the future cultivation of S. superba, reasonable selection and cultivation should be carried out according to the growth potential and disaster resistance of S. superba.

To investigate the effects of varying shading intensities on the growth and photosynthetic physiological characteristics of Cyphomandra betacea seedlings, clarify the optimal light intensity range for seedling growth, and to provide theoretical references and technical guidance for understory intercropping and intensive seedling production.

One-year-old Cyphomandra betacea seedlings were selected as experimental materials. Four shading treatments were established: full sunlight (CK, 100% natural radiation, NR), light shading (S₁, 75% NR), moderate shading (S₂, 50% NR), and severe shading (S₃, 30% NR). Growth and physiological indices including seedling height, ground diameter, single-leaf area and photosynthetic pigments content were measured. Correlation analysis and fuzzy membership function comprehensive evaluation were performed to elucidate the light adaptation mechanism of seedlings.

1) Seedling growth was significantly affected by shading treatments (P<0.05). In the S₁ treatment, seedling height increased by 10.5% compared with the CK group and exhibited the best leaf expansion performance, whereas the S₃ treatment significantly inhibited stem radial growth; 2) Photosynthetic measurements demonstrated that the S₁ treatment maintained a relatively high net photosynthetic rate (7.84 μmol·m^-2·s^-1), with a significantly higher non-photochemical quenching (NPQ) value (11 489.98) than the CK group. Moderate shading was proven to enhance the heat dissipation capacity and effectively alleviate leaf photoinhibition; 3) Correlation analysis showed that seedling height had an extremely significant negative correlation with net photosynthetic rate (r=-0.587, P<0.01), while stomatal conductance was extremely significantly positively correlated with net photosynthetic rate (r=0.731, P<0.01); 4) The fuzzy membership function evaluation results verified that the S₁ treatment was the optimal growth condition, with an average comprehensive value of 26 116.65.

Cyphomandra betacea seedlings can adapt to shading stress via morphological plasticity (plant height promotion and leaf area expansion) and photochemical efficiency regulation. In summary, 75% NR is identified as the optimal light condition for seedling growth, which can be applied to understory intercropping and shading-based intensive seedling cultivation.

To screen strains with good growth-promoting and drought-tolerant effects on C. oleifera, clarify their systematic classification status, and preliminarily explore their mechanisms, which provides a new research direction for improving the drought resistance of C. oleifera.

Drought-tolerant bacteria were isolated and screened from the rhizosphere soil of C. oleifera growing well in a drought environment by using polyethylene glycol (PEG) 6000 to simulate drought stress. Their nitrogen fixation, phosphate solubilization, potassium solubilization, secretion of indole-3-acetic acid (IAA), siderophore and 1-aminocyclopropane-1-carboxylate (ACC) deaminase were determined. Combined with morphological, physiological and biochemical tests and 16S rDNA sequence analysis, the phylogenetic status was clarified. The growth-promoting and drought-resistance were verified by seed germination experiments, and their effects on the activity of antioxidant enzymes and the expression of related resistance genes in the roots of C. oleifera were studied.

A total of 23 strains of bacteria that tolerate 300 g/L PEG6000 drought stress were screened, including 21 strains of nitrogen-fixing bacteria, 16 strains of phosphate-solubilizing bacteria, 5 strains of IAA-producing bacteria, 11 strains of siderophore-secreting bacteria and 6 strains of ACC deaminase-secreting bacteria. Combined with drought tolerance and growth-promoting effects, the optimal strain 1J81 is screened and identified as Enterobacter sichuanensis by morphological characteristics, physiological and biochemical tests and 16S rDNA sequencing results. Under both drought and non-drought conditions, strain 1J81 significantly promotes the activities of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD) and other enzymes in the roots of C. oleifera and the expression levels of related resistance genes POD, SOD1 and PR1B1.

As a microbial fertilizer strain resource, E. sichuanensis 1J81 derived from the rhizosphere soil of C. oleifera has the potential to improve the drought resistance of C. oleifera.

To investigate the growth-promoting effects of ectomycorrhizal fungus-Lactarius deliciosus on Pinus taeda seedlings.

Six-month-old Pinus taeda seedlings were used as the research material, in a constant temperature and humidity light culture environment, the seedlings were inoculated with L. deliciosus solid inoculum and an infection experiment was conducted for a period of two months. A pot-controlled experiment was adopted to evaluate the mycorrhizal colonization rate, growth volume, chlorophyll content of coniferous leaves, changes in antioxidant enzyme activities and malondialdehyde (MDA) content systematically. Subsequently, the changes and enrichment of differentially expressed genes (DEGs) in the transcriptome was analyzed.

L. deliciosus establish a successful symbiotic relationship with Pinus taeda seedlings, exhibiting a strong mycorrhizal effect with a mycorrhization rate reaching 64.29%. Compared to the non-inoculated control group (CK), inoculation with L. deliciosus significantly enhanced seedling growth; the height and ground diameter of mycorrhizal seedlings increased by 29.18% and 20.65%, respectively. Total chlorophyll content increased by 30.85%. Activities of the antioxidant enzymes peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) were enhanced by 43.70%, 61.52% and 37.40%, respectively. Analysis based on transcriptome data showed that differentially expressed genes (DEGs) were significantly enriched in the pathways of phytohormone signal transduction, starch and sucrose metabolism, and phenylpropanoid biosynthesis.

Mycorrhization significantly improved photosynthetic capacity and oxidative stress resistance, ectomycorrhizae may promote seedling growth by modulating hormone signaling networks and secondary metabolic pathways.

To reveal the effects and heterogeneity of ecosystem services (ES) on regional sustainable development (RSD) in world natural heritage sites, address the challenges of coordinating heritage conservation and regional high-quality development, and to provide a scientific basis for sustainable management.

Taking the core zone of the Danxiashan world natural heritage site (a component of the China Danxia world heritage site) and its hosting Renhua County and Zhenjiang district as study units, this research utilized multi-source data across five key time points from 2000 to 2020. The InVEST model was employed to quantify four types of regulating and supporting services. Furthermore, an assessment framework for long-term time-series potential supply of recreational services and a five-dimensional comprehensive RSD index were constructed. Spearman correlation analysis, multivariate controlled regression models, and robustness tests were applied to identify the effects of different types of ES on RSD at different spatial scales.

1) The ES performance of the Danxiashan core zone is generally better than the county-level average. Regulating and supporting services remain stable, while recreational service potential increases by 10.89% in the core zone, higher than the 8.53% at the county scale. Declines in carbon storage and habitat quality are also lower in the core zone; 2) The RSD level increases significantly, with the composite index rising from 0.093 (Year 2000) to 0.903 (Year 2020), an absolute increase of 0.810. After the 2010 world heritage inscription, the region enters a rapid growth stage, and the increase from 2010 to 2015 is 3.7 times that of the previous decade; 3) The effects of different ES on RSD are significantly heterogeneous. Recreational services show a robust positive effect, while regulating services show a significant negative constraining effect. The effects of water yield and soil conservation show no stable statistical significance on RSD; 4) Pronounced spatial scale differences exist in the effects of ES on RSD, and the world heritage inscription policy plays a significant moderating role in the coupling relationship between ES and RSD.

The effects of ES on RSD in world natural heritage sites are characterized by significant type-specific heterogeneity and spatial scale dependencies. Differentiated management strategies should be formulated according to different service types and spatial units. Improving the transformation mechanism from ecological value to RSD is essential to promote the synergistic enhancement of heritage protection and regional sustainable development.

This study aimed to reveal the species-specific patterns of soil cation exchange capacity (CEC) in typical mangrove forests within the specific environment of coastal wetlands, elucidate the multi-scale coupled driving mechanisms involving soil physical properties, chemical properties, and ecological stoichiometric ratios, and verify the ecological suitability of CEC as a core indicator of soil nutrient retention capacity in mangrove ecosystems, thereby providing a scientific basis for precisely enhancing the efficiency of soil fertility regulation in mangrove ecological restoration.

Taking the three typical communities of Aegiceras corniculatum, Sonneratia apetala, and Kandelia obovata as study objects in Maowei Sea, four plots of 20 m × 20 m were set up in each forest, soil samples were collected within each plot using a zigzag pattern to a depth of 0-60 cm, 12 physical and chemical indicators including soil CEC, pH value, organic matter, total nitrogen, and total phosphorus were determined. Correlation analysis, principal component analysis (PCA), variance partitioning analysis (VPA), and partial least squares structural equation modeling (PLS-SEM) were used to explore the key influencing factors of CEC and its coupling mechanism with nutrient retention capacity.

1) Except for nitrate nitrogen, the other 11 soil physical and chemical indicators showed significant differences among tree species (P<0.05); CEC and most nutrient indicators in the 0-20 cm topsoil were significantly higher than those in the subsoil (P<0.05), exhibited an obvious surface accumulation effect; 2) CEC was jointly influenced by soil physical properties, chemical characteristics and ecological stoichiometric ratios. Among them, soil physical properties had the largest total effect (regulating chemical properties through indirect effects), chemical properties had the strongest direct effect, and the two synergistically drove CEC changes, while ecological stoichiometric ratios had the weakest impact; 3) The integrated fertility index (IFI) showed the same order as CEC (Aegiceras corniculatum > Sonneratia apetala > Kandelia obovata), soil CEC and fertility levels were significantly affected by tree species differences, meanwhile, the reliability of CEC as a core indicator of nutrient retention capacity was verified.

The comprehensive soil fertility level of mangroves in the study area was generally medium to low. The soil was rich in organic matter but deficient in nitrogen and phosphorus. The key to maintaining appropriate CEC lies in protecting the natural accumulation of organic matter. It is suggested to adopt artificial regulation measures to accelerate vegetation restoration, promote vegetation succession, improve nitrogen and phosphorus levels, and enhance soil nutrient supply and retention capacity.

To reveal the climate response patterns of radial growth of Cunninghamia lanceolata (Lamb.) Hook. plantations under different competition intensities under the background of climate change, and to provide a reference for formulating targeted survival strategies for Chinese fir stands with varying competition levels.

Taking Jiangle state-owned forest farm in Fujian Province as the research area, 23 standard sampling plots were set up, and tree-ring cores were collected from 171 Cunninghamia lanceolata individuals. Meanwhile, diameter at breast height, tree height and crown width of each tree were measured to calculate the comprehensive competition index (CCI). All sampled trees were classified into three groups by threshold values: low competition group (CCI<1.76, n=45), medium competition group (1.76≤CCI≤3.38, n=82) and high competition group (CCI>3.38, n=44), and standardized tree-ring chronologies were developed for each group. Pearson correlation and partial correlation analyses were adopted to explore the effects of meteorological factors on radial growth characteristics of Chinese fir under different competition intensities. Climate variables with severe multicollinearity (VIF>5) were eliminated via stepwise multiple regression, and climate response models for radial growth of Cunninghamia lanceolata under various competition gradients were finally established.

1) Correlation analysis indicated that the radial growth of Chinese fir in the high-competition group exhibited the strongest sensitivity to meteorological factors, showing highly significant correlations with precipitation of the previous October and the standardized precipitation evapotranspiration index (SPEI) in March of the current year. The radial growth of trees in the medium-competition group was mainly correlated with relative humidity in January and temperature from March to April of the current year, while radial growth in the low-competition group had significant associations with temperatures during the non-growing season and early growing season; 2) The adjusted coefficients of determination of the stepwise multiple regression models for the high-, medium- and low-competition groups were 0.772, 0.518 and 0.363, respectively, all reaching significant levels. The radial growth of Chinese fir under high competition was markedly affected by non-growing season precipitation as well as minimum and maximum temperatures during the growing season. Early growing season temperature dominated the growth variations of trees in the medium-competition group, whereas non-growing season precipitation and early growing season minimum temperature exerted dominant impacts on radial growth in the low-competition group.

Meteorological factors including temperature, precipitation and relative humidity are core drivers regulating the radial growth of Cunninghamia lanceolata. Stand competition intensity can significantly alter the response magnitude of Chinese fir to climate fluctuations. Differentiated tending and management schemes should be implemented for Cunninghamia lanceolata plantations according to stand competition levels.

This study aims to investigate the spatiotemporal evolution patterns of the “production-living-ecological space” and habitat quality, uncover their intrinsic linkages and the underlying mechanisms driving habitat quality changes, and to provide a scientific foundation for optimizing territorial spatial planning and promoting the coordinated development of ecological conservation and economic growth in arid regions.

Taking Xinjiang as the study area, four periods of land use data (1990, 2000, 2010, and 2020), were analyzed integrated with natural factors (elevation, slope, aspect, soil type, annual average precipitation, annual average temperature, and annual average evapotranspiration) and socioeconomic factors (GDP). The spatiotemporal dynamics of the three spaces were examined using a land use transition matrix, land use dynamic degree, gravity center transfer model, and standard deviational ellipse. Habitat quality was assessed using the InVEST model, while the ecological impacts of land use transitions were quantified through an ecological contribution rate analysis. Geoprobe was employed to identify key drivers of habitat quality and their interactive effects.

1) From 1990 to 2020, ecological space dominated the three spaces in Xinjiang (accounting for over 96%), yet it continuously decreased in extent, whereas production space (particularly agricultural land) and living space expanded steadily. Spatially, ecological space was primarily distributed along mountainous regions, while production and living spaces clustered within oases; 2) Overall habitat quality remained low, characterized by a persistent dominance of medium- and low-quality areas and fragile high-quality patches. Low-quality habitats exceeded 60% of the total area; medium-quality habitats showed gradual improvement; high-quality habitats were concentrated in mountain ranges such as the Tianshan and Altai mountains but exhibited a fluctuating decline in area. Habitat degradation evolved from widespread, diffuse expansion toward localized, point-source deterioration; 3) The ecological consequences of three-space transformation varied significantly across phases: from 1990 to 2000, degradation far outweighed improvement; however, from 2010 to 2020, improvement and degradation reached near equilibrium, indicating enhanced synergy between ecological protection and socioeconomic development; 4) Spatial variations in habitat quality were predominantly governed by natural factors, ranked by explanatory power (q-value) as soil type > annual average precipitation > annual average evapotranspiration > annual average temperature. Interactions among natural factors exhibited nonlinear enhancement, whereas socioeconomic factors (GDP) exerted minimal influence.

Over the past three decades, the configuration of the three spaces in Xinjiang has undergone substantial transformation. The contraction of ecological space and concurrent expansion of production and living spaces have critically impacted habitat quality, which remains generally low and primarily regulated by natural conditions-particularly soil properties and hydrothermal regimes. Future strategies should prioritize the optimization of territorial spatial structures and strengthen ecological restoration efforts to ensure both ecological security and sustainable economic development in arid environments.

To investigate the effects of stand densities on the structure of understory plant communities, species diversity and soil nutrient content in Juglans mandshurica forests, and to reveal the intrinsic relationship between plant diversity and soil nutrients.

This study focused on natural secondary forests of Juglans mandshurica on Mao'er mountain with different densities (840, 680 and 480 trees·hm^-2). Through field community surveys and indoor soil analysis, the species composition, importance values, diversity index of understory woody and herbaceous plants were investigated, and soil nutrient indicators at different soil layer depths were measured for correlation analysis.

1) A total of 65 plant species were surveyed under the Juglans mandshurica tree forest throughout the study area, including 16 woody species belonging to 11 families and 14 genera, and 49 herbaceous species belonging to 28 families and 45 genera; 2) The dominant species of the woody layer is Syringa reticulata subsp. amurensis, with a maximum importance value of 85.23% at a stand density of 480 trees·hm^-2; the dominant species of the herbaceous layer is Beckmannia syzigachne, with a maximum importance value of 50.49% at a stand density of 680 trees·hm^-2; 3) Species richness is highest when the stand density is 680 trees·hm^-2, with the richness indices of woody and herbaceous plants being 11 and 31, respectively; the Simpson and Shannon-Wiener diversity indices show a trend of first increasing and then decreasing as stand density decreases, reaching their highest values at a stand density of 680 trees·hm^-2; the evenness index increases as stand density decreases, and the highest evenness index for herbaceous plants is 0.81 at a stand density of 480 trees·hm^-2; 4) The nutrient content in the soil is highest in the 0-10 cm layer. When the stand density is 680 trees·hm^-2, the contents of organic matter, total nitrogen, alkaline nitrogen and available phosphorus in this soil layer are significantly higher than those in other density treatments. Woody plant diversity is extremely significantly positively correlated with total soil nitrogen content and significantly negatively correlated with soil pH, while herbaceous plant richness is extremely significantly positively correlated with the content of available phosphorus.

A stand density of 680 trees·hm^-2 is the optimal density in the study area for maintaining understory plant diversity in Juglans mandshurica forests and enhancing soil fertility. Stand density indirectly regulates the composition and diversity of plant communities by altering the soil environment, this study will provide a reasonable management density for secondary forests of Juglans mandshurica and offer a scientific basis for the sustainable management of Juglans mandshurica.

This study aimed to elucidate the seasonal patterns of cambial activity and the anatomical changes of the secondary phloem of Taxodium mucronatum×Cryptomeria fortunei and to provide anatomical evidence for its cultivation and wood-quality regulation.

Approximately 50-year-old T. mucronatum×C. fortunei trees growing in Nanjing were sampled monthly from April to November at breast height. Stem transverse sections were prepared using the paraffin-embedding method and observed under fluorescence and polarized light microscopy. The number of cambial cell layers, the width of conductive secondary phloem, and the number of callose deposition sites were measured.

The number of cambial cell layers ranged from 3 to 12 during April-November, with 3-4 layers in mid-April, an increase to 8-12 layers during May–June (the annual peak), and a decline to about 3 layers during October-November. This pattern showed a unimodal seasonal fluctuation. The width of conductive secondary phloem increased progressively throughout the growing season and reached its maximum in November (760.40±179.72 μm). Callose deposition between sieve cells increased from 10 sites in April to 22 sites in November, with an average of 19 sites during September–October and a clear rise in fixed callose, indicating that peripheral sieve cells withdrew from the conductive zone toward the end of the growing season.

Under the subtropical monsoon climate of Nanjing, Taxodium mucronatum×Cryptomeria fortunei exhibits a prolonged cambial activity period and maintains a relatively wide belt of conductive secondary phloem during the late growing season. The seasonal progression of callose deposition reflects the gradual transition of sieve-cell function in response to the long growing season. Using representative anatomical indicators and their seasonal dynamics, this study revealed the coordinated annual changes of the cambium and secondary phloem in this species.