To investigate the morphological characteristics and germination traits of Rhododendron delavayi seeds from six provenances in Guizhou Province, analyze the variation and genetic characteristics of seeds from different provenances, and to provide technical support for the breeding of superior varieties.

The morphological traits (seed length, width, thickness, length-to-width ratio, flattening rate, seed dimension index, and thousand-seed weight) and germination traits (radicle length, germination rate, germination potential and germination index) of seeds from the six provenances were subjected to variability and heritability analysis, correlation analysis, and cluster analysis. The seed quality from different provenances was comprehensively evaluated using principal component analysis.

The results showed that the morphological characteristics of R. delavayi seeds from different provenances exhibited extremely significant differences (P<0.01). The coefficient of variation for seed morphological traits exceeded 10.00%, with the smallest variation observed in thousand-seed weight. The coefficients of variation for seed dimension index, seed thickness, and length-to-width ratio all exceeded 30.00%. The broad-sense heritability of morphological traits was greater than 0.87. The germination traits of seeds from different provenances also showed significant differences (P<0.05). Seeds from the Bailidujuan management area exhibited the longest radicle length (5.17 mm), the highest germination rate (77.50%), and the greatest germination potential (20.00%). Correlation analysis indicated that seed length and length-to-width ratio were significantly (P<0.05) or extremely significantly (P<0.01) negatively correlated with germination rate, germination potential, and germination index. Seed width was significantly (P<0.05) or extremely significantly (P<0.01) positively correlated with radicle length, germination rate, and germination index. The six provenances could be classified into three major categories: the first category included Zhongshan District, Shuicheng District, and Bailidujuan Management Area; the second category included Xixiu District and Hezhang County; and the third category was Changshun County. The comprehensive evaluation of seed quality from different provenances ranked as follows: Zhongshan District > Shuicheng District > Bailidujuan Management Area > Hezhang County > Changshun County > Xixiu District.

In conclusion, the morphological characteristics of R. delavayi seeds are primarily influenced by genetic factors but also exhibit certain variations due to geographical and environmental factors across different provenances. Seeds from Zhongshan District and Shuicheng District were relatively superior and can be further studied as material for breeding and propagation.

To explore the effects of different nitrogen, phosphorus, and potassium fertilizer levels on the photosynthetic characteristics, yield, and fruit quality of ‘Menguan 1’. and to provide reasonable fertilization recommendations for the cultivation of this variety in the eastern part of the northern Tianshan mountains in Xinjiang.

Six-year-old Xanthoceras sorbifolium ‘Mengguan 1’ trees grown in Xinjiang were used as the experimental materials. A “3414” fertilizer-response experimental design was adopted, in which nitrogen, phosphorus, and potassium were each assigned four application levels: 0 (no fertilization), 1 (50% of the conventional fertilization rate), 2 (the conventional fertilization rate), and 3 (150% of the conventional fertilization rate). The conventional fertilization rates were defined as 0.75 kg pure N plant^-1, 0.60 kg P₂O₅ plant^-1, and 0.20 kg K₂O plant^-1. On this basis, the effects of different N-P-K fertilization combinations on leaf photosynthetic characteristics, light-response parameters, fruit morphology, and seed yield were systematically evaluated. The rectangular hyperbolic model (RH), non-rectangular hyperbolic model (NRH), exponential model (EX), and modified rectangular hyperbolic model (MRH) were used to fit the P_n-PAR curve, and the photosynthetic parameters (P_n, T_r, C_i, WUE) and yield and quality were analyzed.

The MRH model provided the best fit, with the calculated AQY, LCP, R_d, P_nmax, and LSP being closest to the measured values. The application of conventional nitrogen fertilizer (N₂P₂K₂) significantly increased leaf P_n, while high potassium fertilizer (N₂P₂K₃) significantly enhanced the WUE of ‘Menguan 1’. Compared to the control (N₀P₀K₀), P_n increased by 57.01% and WUE by 93.62%. Regarding yield and fruit traits, the fertilization ratios of N₂P₂K₂ and N₂P₃K₂ increased the single-plant yield by 68.17% and 62.28%, respectively, compared to N₀P₀K₀. The former increased seed number, fruit diameter, single fruit weight, and single seed weight by 31.50%, 14.91%, 56.50% and 115.21%, respectively, while the latter increased oil content by 14.03%.

When the pure amounts of nitrogen, phosphorus, and potassium fertilizers were 413.54 kg/hm², 613.64 kg/hm², and 213.44 kg/hm², respectively, the photosynthetic characteristics, yield, and fruit quality of ‘Menguan 1’ could be effectively improved.

To explore the effects of different nitrogen application rates on the growth of transplanted seedlings of Phoebe neurantha (Hemsl.) Gamble cv. ‘Fengweinan’ Y.J. Fei, and to provide a theoretical basis for the efficient utilization of exogenous nitrogen in transplanted seedlings of this cultivar.

A pot experiment was conducted to compare the performance of one-year-old bare-root transplanted seedlings (L) and soil-root-ball transplanted seedlings (T) under five nitrogen application gradients: 0 (CK), 100 (ZN1), 200 (ZN2), 300 (ZN3), and 400 mg/plant (ZN4). The aim was to determine the optimal nitrogen application rate for transplanted ‘Fengweinan’ seedlings.

For bare-root transplanted seedlings (L), the total root length reaches its peak at ZN2, which is 81% higher than that of the control (CK). For soil-root-ball transplanted seedlings (T), multiple growth indicators are optimal at ZN3: plant height, ground diameter, total root length, and leaf length are significantly increased by 29%, 56%, 102%, and 103% compared with CK, respectively. The photosynthetic pigment content of both types of transplanted seedlings first increases and then decreases with the increase of nitrogen application rate. For bare-root transplanted seedlings, the photosynthetic pigment content is the highest at ZN2, and the basic photosynthetic parameters of the seedlings reach their maximum values, with net photosynthetic rate and transpiration rate significantly increased by 170% and 166% compared with CK, respectively. For soil-root-ball transplanted seedlings, the photosynthetic pigment content is the highest at ZN3, but the peaks of photosynthetic rate and transpiration rate appear at ZN4. Appropriate nitrogen application can increase the contents of soluble sugar, soluble starch, and organic nitrogen compounds, and enhance the activities of nitrogen metabolism enzymes. Excessive nitrogen application (under ZN4 treatment) leads to a 36% increase in root soluble protein content compared with ZN3, but decreases in soluble sugar, soluble starch contents, and nitrogen metabolism enzyme activities. Specifically, the soluble starch content in roots, total nitrogen in underground parts, and leaf nitrate reductase activity in the ZN4 treatment group are 28%, 7%, and 10% lower than those in the ZN3 treatment group, respectively.

Moderate nitrogen application promotes seedling growth by enhancing photosynthetic performance and carbon-nitrogen metabolism. The optimal nitrogen application rates for bare-root seedlings and soil-balled scedings are 200 mg per plant and 300 mg per plant, respectively.

Through the analysis of soil characteristics in main Camellia oil producing areas in Hainan Island, this paper aims to reveal the geographical distribution characteristics of nutrients in Camellia oil forest soil in Hainan Island, and comprehensively evaluates the soil characteristics and fertility in Camellia oil forest land in Hainan Island.

The study measured 15 sample plots from the main Camellia oil production areas in Hainan Island, evaluating key parameters including bulk density, total porosity, capillary porosity, non-capillary porosity, moisture content (weight/volume), maximum capillary water retention, field water retention, saturated moisture content, soil solid-liquid-gas ratio, pH, organic carbon, organic matter, total nitrogen, total phosphorus, total potassium, nitrate nitrogen, ammonium nitrogen, alkaline-hydrolyzed nitrogen, available phosphorus, fast-acting potassium, slow-release potassium, cation exchange capacity, microbial nitrogen biomass, and microbial carbon biomass. Significant differences were analyzed using Duncan's multiple comparisons, visualized through correlation heat maps, and principal component analysis (PCA) was conducted to extract principal components. Comprehensive scores were calculated for ranking purposes.

The soil samples showed significant variations in moisture content: HK-1 and CM-2 had the highest relative moisture levels (62.54%-67.15%). Among the three phases (solid, liquid, and gas), the HK series (HK-1 and HK-2) contained the lowest proportion of solid matter (39.21%-43.05%) but higher air content (26.48%-30.23%). HK-2 demonstrated the highest total porosity [(60.79±4.48)%], weight moisture content [(32.35±0.65)%], total phosphorus (TP) (1 222.66±113.41 mg·kg^-1), and available potassium (AK) (210.80±1.61 mg·kg^-1). QH-3 recorded the highest bulk density (1.69±0.13 g·cm^-3), while CM-2 showed the highest organic carbon (OC) (24.13±0.45 g·kg^-1), organic matter (OM) (41.60±0.76 g·kg^-1), cation exchange capacity (CEC) (8.89±0.35 cmol⁺·kg^-1), and maximum specific binding capacity (MBC) (544.35±2.60 mg·kg^-1). DA-2 had the highest pH value (6.88±0.05), BT-2 exhibited the highest total nitrogen (TN) (1.83±0.18 g·kg^-1) and maximum binding capacity (MBN) (54.40±3.31 mg·kg^-1), while QH-1 showed the highest nitrate nitrogen (NO₃-N) (53.34±1.12 mg·kg^-1). Significant differences in soil quality were observed across different sample plots, with comprehensive scoring and ranking effectively distinguishing quality grades, confirming HK-2 as the most fertile.

Significant discrepancies in soil physical properties and nutrient profiles were identified across the principal oil-tea camellia cultivation areas of Hainan Island. Among the sampled plots, HK-2 and HK-1 exhibited the most favorable integrated soil functionality, whereas CM-2, BT-2, and HK-2 demonstrated particularly superior performance in key nutrient indicators. In contrast, plots WZS-1, CM-1, and QH-3 were characterized by pronounced soil compaction, nutrient deficiency, or strong acidification. These findings provide a critical scientific foundation for the precision management, targeted amelioration, and sustainable utilization of soil resources in oil-tea camellia production systems..

The study aims to investigate the effects of climatic factors and interspecific competition on the radial growth of Pinus koraiensis, and to provide scientific support for predicting forest productivity and carbon sink potential under future climate change, as well as the conservation and sustainable management of regional forest resources.

Pinus koraiensis trees from two national nature reserves (Xiaobeihu and Xilinhe) in the mountainous eastern Heilongjiang Province were selected as research materials. Dendrochronological techniques were adopted to acquire radial growth data. Combined with meteorological datasets and neighborhood competition indices, correlation analysis and linear mixed-effects models (LMM) were applied to quantify the independent impacts of climate and competition on the radial growth of Pinus koraiensis. Variance decomposition was further performed to calculate their relative contributions, so as to explore the effects of climatic conditions and neighborhood competition on radial growth as well as corresponding regional disparities.

1) The radial growth of Pinus koraiensis in the Xiaobeihu study area showed significantly positive correlations with temperatures of the previous winter and current spring. Linear mixed-effects model (LMM) outputs indicated that the diameter at breast height (DBH) of competing trees achieved the optimal fitting performance with cumulative radial growth over the past 20 years; 2) Radial growth of Pinus koraiensis in the Xilinhe study area was primarily controlled by March temperature of the current year. LMM results revealed that DBH of neighboring competitive trees had the best fitting effect with cumulative growth over the recent 10 years; 3) The contribution proportions of climatic factors and inter-tree competition differed along the latitudinal gradient. With increasing latitude, the relative contribution rate of climate rose from 39% to 88%, while that of competition decreased from 61% to 11%.

This study indicates that the dominant factor regulating radial growth of Pinus koraiensis shifts from biotic competition to climatic limitation along mountainous eastern Heilongjiang. Thinning can alleviate competitive pressure in low-latitude forest stands, while high-latitude forests should be alert to growth stress induced by spring warming.

Aiming at the industrial problems of low yield, low efficiency and high labor cost in the management of Camellia oleifera forests, this study explored the regulatory effects of mechanized fertilization in autumn on photosynthetic carbon assimilation capacity, oil synthesis and yield of four major promoted C. oleifera cultivars in Hunan Province, so as to provide a theoretical and technical basis for yield and quality improvement as well as precision fertilization of C. oleifera.

Fourteen-year-old C. oleifera forests of four cultivars, namely ‘Huashuo’, ‘Huajin’, ‘Huaxin’ and ‘Xianglin 210’, were selected as test materials. The mechanized fertilization experiment was conducted in late September 2024. Three treatments were set up, including compound fertilizer (CF), phosphorus-potassium fertilizer (PP) and no-fertilizer control (CK). Photosynthetic gas exchange parameters (net photosynthetic rate, transpiration rate, stomatal conductance, intercellular CO₂ concentration, water use efficiency, etc.), chlorophyll content, yield per unit area, fruit oil content and fatty acid composition were determined in late October before fruit harvesting and early December.

Compared with CK, CF treatment increases the chlorophyll content, net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, water use efficiency, kernel oil content, oleic acid proportion, linoleic acid proportion and total polyphenol content of all C. oleifera cultivars in late October. In particular, the chlorophyll content of ‘Huaxin’ and ‘Huajin’ is significantly improved (P<0.05), and the net photosynthetic rate and water use efficiency values of ‘Huaxin’, ‘Huashuo’ and ‘Xianglin 210’ also rise significantly (P<0.05). PP treatment extremely and significantly enhances the chlorophyll content of two late-maturing cultivars (‘Huashuo’ and ‘Xianglin 210’) (P<0.05), promotes linoleic acid synthesis in ‘Huaxin’, ‘Huajin’ and ‘Xianglin 210’, and markedly improves the yield of ‘Xianglin 210’. In early December, compared with CK, CF treatment continuously and significantly increases the chlorophyll content of ‘Huajin’, ‘Huashuo’ and ‘Xianglin 210’, and all cultivars maintain high levels of net photosynthetic rate and water use efficiency. PP treatment sustainably elevates the chlorophyll content of the two late-maturing cultivars ‘Huashuo’ and ‘Xianglin 210’ with significant differences (P<0.05).

Autumn application of compound fertilizer (CF) significantly improves the photosynthetic efficiency, chlorophyll content and oil quality of C. oleifera, which is regarded as the optimal fertilization scheme. Phosphorus-potassium fertilizer (PP) exerts remarkable effects on linoleic acid synthesis, yield and kernel oil content of ‘Huaxin’, ‘Huajin’ and ‘Xianglin 210’. In summary, compound fertilizer is recommended as the first choice for field application, and phosphorus-potassium fertilizer can be additionally applied before fruit harvesting according to the botanical characteristics of specific cultivars.

This study aims to investigate the effects of water stress on the growth, biomass allocation, and physiological characteristics of seedlings of three afforestation tree species, in order to screen for species with strong drought resistance and to provide a scientific basis for water-saving and drought-resistant afforestation in arid areas.

Two-year-old seedlings of Elaeagnus angustifolia, Populus euphratica, and Xanthoceras sorbifolium were subjected to four water treatments: 75%-80% of field capacity (CK), 60%-65% of field capacity (T1), 45%-50% of field capacity (T2), and 30%-35% of field capacity (T3). Seedling growth, physiological and biochemical indices, and biomass allocation patterns under water stress were systematically measured, and the differences in the responses of the seedlings of each tree species to water stress were analyzed.

1) With increasing water stress, the increments in height and ground diameter of the three tree species seedlings generally decreased. Among them, E. angustifolia seedlings exhibited the largest increments in height and ground diameter across all water treatments, and the three species showed the smallest reductions in height and ground diameter growth under the T1 treatment; 2) As water stress intensified, the root, stem, and leaf biomass of the three tree species seedlings significantly decreased, while the root-to-shoot ratio (R/S) significantly increased. Among them, X. sorbifolium seedlings exhibited the greatest increase in R/S, whereas E. angustifolia seedlings accumulated the highest root, stem, and leaf biomass across all treatments; 3) With increasing water stress, chlorophyll content and value of photosynthetic parameters such as net photosynthetic rate (Pn) and stomatal conductance (Gs) significantly decreased (P<0.05). Notably, P. euphratica seedlings had significantly higher valuse of Pn, Gs, and other photosynthetic parameters than the other two species (P<0.05), while the water use efficiency (WUE) of E. angustifolia seedlings was significantly higher than those of the other two species under the T3 treatment (P<0.05); 4) As water stress intensified, the malondialdehyde (MDA) content, osmoregulatory substance content, and the activities of superoxide dismutase (SOD) and peroxidase (POD) generally increased across the three species. Among them, E. angustifolia seedlings exhibited relatively higher chlorophyll content, osmoregulatory substance contents, and POD activity, while X. sorbifolium seedlings showed relatively higher MDA content.

Under water stress, the growth of the three tree species seedlings was inhibited to varying degrees, with multiple photosynthetic indices significantly decreasing and stress-resistant physiological indices showing an increasing trend. However, the three species were ranked in drought resistance as follows. Based on the comprehensive evaluation results using the membership function method, the drought resistance of the three tree species seedlings ranked as follows: E. angustifolia showed the strongest resistance, followed by P. euphratica, and X. sorbifolium showed the weakest resistance.

This study aims to understand the status, spatial distribution of Chinese fir king resources nationwide and their relationships with environmental factors.

ArcGIS spatial analysis method was used to study the spatial distribution pattern of Chinese fir kings across the country, and the correlations between their distribution and environmental factors such as altitude and temperature were explored.

There are 278 ancient Chinese fir trees meeting the Chinese fir king standard nationwide, among which 91, 101 and 86 trees meet the national first-, second-, and third-class ancient tree standards respectively. The quantity of Chinese fir king resources varies greatly among different distribution regions in China: 54.32% of Chinese fir kings are distributed in the eastern part of the middle zone, and 38.49% in Fujian Province. There are 18 Chinese fir kings with an age over 1 000 years, 30 with a height over 40 m, 5 with a diameter at breast height (DBH) over 2.1 m, and 24 with a crown width over 20 m. The spatial distribution of Chinese fir kings nationwide exhibits a spatial agglomeration characteristic, with high-density core distribution areas covering the junction of northern Fujian and southern Zhejiang, the junction of Guizhou, Guangxi and Hunan, and western and southern Fujian. The quantity of Chinese fir king resources is negatively correlated with the population density of the distribution area, and positively correlated with the radius of the river buffer zone in the distribution area. Most Chinese fir kings are distributed in low-hotspot areas of traditional villages and regions with an altitude of 600-900 m, and the majority grow on forestlands. The height of Chinese fir kings is significantly correlated with local temperature factors and significantly positively correlated with slope; their DBH is significantly positively correlated with local altitude; their crown width is significantly correlated with local wettest-month rainfall and altitude; and their age is significantly negatively correlated with local annual average temperature and maximum temperature of the warmest month.

Chinese fir kings across China exhibited a spatially clustered distribution, with high-density core areas mainly located in northern Fujian and southern Zhejiang, which are traditional Chinese fir-producing regions. This spatial aggregation reflects the environmental adaptability of Chinese fir and provides valuable references for the conservation of ancient Chinese fir trees and the management of Chinese fir plantations. Moreover, 65.10% of Chinese fir kings were distributed within hotspot areas of traditional villages, further demonstrating that the distinctive awareness of protecting ancient Chinese fir trees, shaped by local people's reverence for these trees, has contributed to their long-term preservation.

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.

A systematic study was conducted on the flowering biological characteristics of Bambusa emeiensis L. C. Chia & H. L. Fung to clarify the flowering rhythm of bamboo species under artificial cultivation conditions, so as to provide a scientific basis for the effective implementation of cross-breeding of Bambusa emeiensis.

Two clonal lines of Bambusa emeiensis, DTW and JJS, transplanted in Hangzhou were used as research materials. The forest appearance and flowering phenology of the two clones were observed via field investigation. The morphological structure of floral organs was observed and recorded by dissecting spikelets. Pollen viability was detected using the iodine-potassium iodide (I₂ - KI) staining method and in vitro germination assay, while stigma receptivity was examined with the benzidine-hydrogen peroxide method. The breeding characteristics of the two clones were analyzed by estimating the pollen-ovule ratio (P/O).

1) The two clones of B. emeiensis L. C. Chia & H. L. Fung exhibited identical flowering periods, with full bloom from mid-May to early August, and a few florets continued to open for another two weeks thereafter; 2) The spikelets of the DTW clone are purple - brown overall, while those of the JJS clone are purple-brown with a slight green tint. The anthers of the DTW clone are 5.48±0.55 mm long and yellowish-brown, while those of the JJS clone are 4.51±0.32 mm long and bright red; 3) The pollen viability and germination rate of both the DTW and JJS clones reach their peaks when the anthers are completely exposed. The optimal pollen viability is achieved in May and July, with the proportions of strong pollen viability being 75.2% and 79.2% respectively. The optimal germination rates are achieved in June and July, with the proportions of good germination being 4.3% and 4.9% respectively; 4) Both clones exhibited the strongest stigma receptivity during anther dehiscence; 5) Under artificial pollination, the seed-setting rate reached 4.00% for DTW and 2.67% for JJS, while no seed-setting was observed under natural pollination conditions in either their original habitats or transplanted habitats.

The flowering characteristics of the two clones of B. emeiensis L. C. Chia & H. L. Fung are different, and their flowering is not synchronized under the same environmental conditions. The DTW clone is suitable for pollination in June, while the JJS clone is suitable for pollination in July, but both clones possess a certain degree of fertility. Although the overall fertility of the two clones is relatively low, they can still serve as breeding materials.

This study aimed to explore the effects of stratification treatment on breaking the dormancy of Celtis sinensis seeds. The changes in nutrients, endogenous hormones and key enzyme activities during the stratification process were analyzed to clarify its hibernation release mechanism and find the best method for breaking seed dormancy.

Three treatment methods were adopted for Celtis sinensis seeds: variable temperature stratification, low-temperature stratification, and gibberellin combined with low temperature stratification. The physiological indicators such as soluble sugar, soluble protein, starch, crude fat, glucose-6-phosphate dehydrogenase (G-6-PDH), lipase, indole acetic acid (IAA), gibberellin (GA₃), zeatin riboside (ZR), and abscisic acid (ABA) of the seeds under different stratification stages were detected to analyze the changing trends of these physiological indicators during the stratification process.

Stratification treatments can significantly increase the germination rate of Celtis sinensis seeds. The effect of gibberellin combined with low temperature stratification treatment is the best, with a germination rate of 54.7% after 100 days of stratification. As the stratification process progresses, the trends of physiological indicators in each treatment are similar: soluble sugar increased first and then decreased, and soluble protein, starch and crude fat were decomposed continuously. The activity of lipase and G-6-PDH enzyme was enhanced continuously. IAA increased first and then decreased, ABA decreased continuously, and the contents of GA₃ and ZR increased continuously. The ratios of IAA/ABA, GA₃/ABA and ZR/ABA increased continuously. Gibberellin combined with low temperature stratification treatment showed significantly higher enzyme activity and GA₃ content in the middle and later stages of stratification compared to the other two treatments, while the ABA content was significantly lower than those of the other two treatments.

Stratification treatment effectively broke the dormancy of Celtis sinensis seeds, and the method of gibberellin combined with low temperature stratification is the best. During the stratification process, the nutrients, enzyme activities and endogenous hormone contents within the seeds are mutually transformed, jointly promoting the transition of Celtis sinensis seeds from dormancy to germination.

This study aims to explore the effects of different treatment conditions on chromosome root tip squashing, optimize the chromosome preparation method, conduct karyotype analysis of 13 Camellia species, and to provide a theoretical basis for the research on Camellia plants.

The effects of different pretreatment and dissociation conditions on chromosome slide preparation were compared to select a universally applicable method for Camellia species. Karyotype analysis of 13 Camellia species was conducted using the optimized method, yielding karyotype diagrams, parameters, and evolutionary trends for each species.

The optimized pressing method suitable for Camellia is to treat the root tips with saturated 1,4-dichlorobenzene for 6 h, then place in a 1 mol/L hydrochloric acid water bath at 60 ℃ for 15 minutes and stain with a modified carbol-fuchsin solution for 15 minutes for the conventional pressing operation. All 13 Camellia species exhibit a chromosome base number of x=15, the results of the karyotype analysis show that the karyotypes include diploid, tetraploid, hexaploid, and octoploid. Among diploids, the karyotype formula for C. semiserrata is 2n=2x=30=24m+6sm, and for the C. chekiangoleosa, it is 2n=2x=30=22m+8sm; for the tetraploid C. meiocarpa, the karyotype formula is 2n=4x=60=40m+20sm; among the hexaploid species, the karyotype formula for C. oleifera is 2n=6x=90=42m+44sm+4st, and for C. drupifera, it is 2n=6x=90=60m+26sm+4st; additionally, the karyotype formula for the octaploid C. gauchowensis is 2n=8x=120=94m+26sm. The range of asymmetry indexes for 13 Camellia species is 47.90%–64.63%, the relative length of chromosomes ranges from 2.78 to 13.59, the arm ratios range from 1.00 to 4.22, and the Lt/St ranges from 1.62 to 4.89. According to the Stebbins' karyotype classification system, the C. sinensis, C. chekiangoleosa, C. transarisanensis, and C. meiocarpa are of type 2A, C. boreali-yunnanica is type 1A, and C. osmantha is type 2C, while the remaining eight species are type 2B.

This study explored chromosome staining techniques widely applicable to Camellia, determined the chromosome numbers and ploidy levels of 13 Camellia species, and reported the karyotypes of C. transarisanensis, C. cordifolia, and C. osmantha for the first time. It provides an important reference for chromosome preparation and karyotype analysis of Camellia sinensis plants.

To explore the effects of process parameters on the cutting performance of moso bamboo during chainsaw cutting, and to establish a mechanism characterization method applicable to hollow round bamboo structures.

3-5-year-old moso bamboo was selected as the test material. A dedicated test bench for bamboo chainsaw cutting was constructed. Chainsaw specification, bamboo diameter, feed speed, and moisture content were selected as experimental factors, and peak cutting force and specific sawing energy were adopted as evaluation indices. Single-factor tests and L₉(3⁴) orthogonal array tests were conducted. In addition, the equivalent single-tooth average cutting thickness and normalized peak cutting force were introduced to carry out mechanism analysis.

The results showed that when moisture content increased from 40% to 80%, peak cutting force decreased from 48.14 to 34.29 N, and specific sawing energy decreased from 13.4 to 8.1 J/cm³. As bamboo diameter increased from 70 mm to 110 mm, peak cutting force increased from 31.18 to 52.40 N. When feed speed increased from 8 mm/s to 32 mm/s, peak cutting force increased from 26.44 to approximately 90 N, and specific sawing energy reached its relatively low value at around 24 mm/s. The orthogonal test results indicated that the factors affecting peak cutting force rank in descending order of influence magnitude as feed speed, chainsaw specification, moisture content and bamboo diameter. For specific sawing energy, the order of factor influence magnitude is chainsaw specification, feed speed, moisture content and bamboo diameter. Mechanism analysis revealed that when the equivalent single-tooth average cutting thickness increased from 0.07 mm to 0.41 mm, the peak cutting force increased from 18.66 to 101.51 N. The normalized peak cutting force exhibits a linear upward trend with the increase of equivalent single-tooth average cutting thickness, with a coefficient of determination R² of 0.702.

This study demonstrated that the peak cutting load of moso bamboo during chainsaw cutting is mainly controlled by single-tooth chip load. Moisture content, bamboo diameter, and chainsaw specification exert a modifying effect on cutting performance. The equivalent single-tooth average cutting thickness and normalized peak cutting force can be used to characterize the cutter tooth load and the stress intensity per unit effective cutting area in the chainsaw cutting of moso bamboo.