Guangdong Academy of Forestry

The abundance distribution of species varies during the natural restoration of plant communities, and the initial abundance patterns influence future community dynamics. Understanding these patterns can help optimize species selection and allocation in forest revegetation. This study examines 10 different mangrove communities in the coastal wetland of Nansha, Guangzhou, analyzing their taxonomic composition and similarity of plant communities. Rank-abundance curves (RACs) were used to quantify species abundance patterns across these communities. The results showed that: (1) the flora of Nansha coastal wetland is relatively homogeneous with plant species concentrated in a few families and genera. The wetland hosts 42 vascular plant species from 29 families and 40 genera, including 31 species from 18 families and 29 genera of Spermatophyta, and 11 species from 11 families and 11 genera of ferns. Common families include Araceae, Primulaceae, and Pteridaceae while common genera include Alocasia, Ardisia and Acrostichum. (2) Rank-abundance curves exhibited an inverse J-shape across all three vegetation strata, except for the species-family and genus-family distributions in the Aegiceras corniculatum community. RAC steepness (k values) varied widely, and species evenness differed significantly among communities. (3) Mangrove communities exhibit diverse life forms, including evergreen trees, shrubs (including semi-shrubs), ferns and perennial herbs. Restoration and plantation efforts should prioritize native mangrove species while promoting species richness and reducing rare species to enhance ecological complementarity. At the same time, it takes into account the problems of limiting proliferation and environmental constraints to optimize its ecosystem functioning.

Cropland encroachment on protected areas (PAs) impedes the achievement of global biodiversity conservation goals. However, the extent and expansion of cropland in PAs as well as regional and protection level differences on timescale, and national drivers thereof remains unassessed. We analyzed the land cover composition of global PAs to identify cropland changes from 1985 to 2020 and visualized cropland encroachment degree of PA patches by calculating cropland grid density (CGD) which is defined as the amount of cropland grids per square kilometer. We further identified nations’ economic and agricultural development indicators as the primary drivers of cropland encroachment through correlation analysis and GLM method. The results indicate that cropland encroachment on PAs occurs worldwide with significant different level at both regional and protection levels. In western Europe, southern Latin America, central Africa, and southern Asia, a proportion of PA patches have high CGDs. CGDs of Asia and Pacific, Europe and Latin America, and Caribbean PA patches declined, whereas the indices increased in Africa and West Asia. CGDs of PAs with high protection levels are lower than that of PAs with low protection levels. At the national scale, economic development, agricultural development level, and cropland encroachment degree show negative correlations, whereas positively correlated with poverty stress and rural population percentage. The optimal model suggests the GDP per capita, arable land and permanent cropland percentage are significant factors influencing cropland encroachment on PAs. This study highlights the challenges to balance agricultural development and ecological protection and call for a stricter protection on PAs.

This study presents an eco-friendly strategy to valorize Polygonatum cryptonym Hua flavonoids (PC) from the residues of polysaccharide extraction by synthesizing silver nanoparticles (PC-AgNPs) with enhanced bioactivity. Optimized synthesis (pH 7.5, 10 mM Ag⁺, 55 °C, 30 min) yielded monodisperse, spherical PC-AgNPs (avg. 16.2 nm) with face-centered cubic crystal structure. Nanoparticles showed remarkable scavenging ability for DPPH free radical (SC₅₀ = 2.61 µg/mL) and ABTS free radical (SC₅₀ = 1.65 µg/mL) compared to the native PC samples. The PC-AgNPs were incorporated into polylactic acid (PLA) films (1% w/w), achieving superior mechanical performance (tensile strength: 54.6 MPa; elongation at break: 6.0%) while demonstrating broad-spectrum antimicrobial activity against E. coli, S. aureus, and A. niger. Mechanistic studies revealed that the nanocomposite film disrupted bacterial membrane integrity in E. coli. Applied to litchi preservation at -18°C, the 1%NPs/PLA coating effectively maintained mitochondrial enzyme activities (Succinate dehydrogenase, Cytochrome c oxidase, H⁺-ATPase, Ca²⁺-ATPase) at more than 80% of fresh fruit levels for a certain storage life, significantly delaying senescence compared to controls. These findings establish PC-AgNPs/PLA as a dual-functional active packaging material that synergistically combines antioxidant reinforcement, antimicrobial protection, and physiological regulation for postharvest fruit preservation.

The anaerobic environment of mangrove sediments due to periodic tides is conducive to methane (CH4) production, but processes and mechanisms of CH4 emission from mangrove sediments are not yet well understood. We used in situ field monitoring and laboratory experiments to investigate the effects of tides and seasons on CH4 emissions from the sediments of Sonneratia apetala (SA), Kandelia obovata (KO), and Avicennia marina (AM), respectively. Methane emissions from the sediments of all mangrove species were significantly higher in summer than in winter, with overall CH4 fluxes being 2.14 times higher during the after-ebb tide compared to the pre-flood tide. Among the mangrove species, AM (16.77 ± 13.73 mg m−2 h−1) exhibited the highest emissions, followed by SA (1.45 ± 0.90 mg m−2 h−1) and KO (0.14 ± 0.16 mg m−2 h−1). CH4 emissions in three mangrove species were mainly driven directly by abiotic factors, including sediment organic carbon (SOC) that could provide substrate for methanogens to generate CH4, and dissolved CH4 concentration in porewater likely served as a carbon source or turnover state for CH4 to eventually enter the atmosphere. Also, sediment CH4 emissions were suppressed by the α-diversity of methanogenic communities. In addition, pH, CH4 flux, SOC, and redox potential significantly shaped structure of the methanogenic communities, potentially regulating sediment CH4 emissions. This study result highlights that abiotic factors can greatly influence CH4 emissions from mangrove sediments, as well as emphasizes the important role of the sediment-porewater-atmosphere pathway on CH4 emissions.

The purpose of this study was to evaluate the effects of different nitrogen (N), phosphorus (P), and potassium (K) fertilization ratios on the carbon (C), N, and P contents and their ecological stoichiometric characteristics in the leaf–soil–microbial system of Sapindus saponaria and elucidate their relationship with yield. A “3414” experimental design was employed in a 6-year-old Sapindus saponaria woodland located in Fujian Province of China. Fourteen N–P–K fertilization treatments with three replicates were established. Leaf, soil, and microbial samples were collected and analyzed for C, N, and P contents. Redundancy Analysis (RDA), Partial Least Squares Path Modeling (PLS–PM), and the entropy-weighted technique of ranking preferences by similarity to optimal solutions (TOPSIS) were utilized to assess the relationships among variables and determine optimal fertilization strategies. It was found through research that different fertilization treatment methods have a significant impact on both the soil nutrient content and the C, N, and P contents of soil microorganisms. Compared with the control group, soil organic C, total N, and total P, and microbial C, N, and P contents increased by 14.25% to 52.61%, 3.90% to 39.84%, 9.52% to 150%, 6.65% to 47.45%, 11.84% to 46.50%, and 14.91% to 201.98%, respectively. Results from Redundancy Analysis (RDA) indicated that soil organic C, total N, and total P exerted a significant influence on the leaf nutrients. PLS-PM demonstrated that fertilization indirectly affected leaf nutrient accumulation and yield by altering soil properties, with soil total phosphorus and leaf phosphorus being key determinants of yield. Additionally, soil microbial entropy impacted yield by regulating microbial biomass stoichiometric ratios. The entropy-weighted TOPSIS model identified the N2P2K2 treatment (600 kg/ha N, 500 kg/ha P, and 400 kg/ha K) as the most effective fertilization strategy. Optimizing N–P–K fertilization ratios significantly enhances leaf nutrient content and soil microbial biomass C, N, and P, thereby increasing Sapindus saponaria yield. This research clarifies the underlying mechanisms through which fertilization exerts an impact on the C–N–P stoichiometry within the leaf–soil–microbial system. Moreover, it furnishes a scientific foundation for the optimization of fertilization management strategies in Sapindus saponaria plantations.

Proteus mirabilis, an important zoonotic opportunistic pathogen, is widely found in nature and the intestinal tracts of animals, which can cause diarrhea, pneumonia, urinary tract infections, and other symptoms in domestic animals including sheep, pigs, cattle and chickens. In this study, necropsy of a deceased critically endangered Malayan pangolin revealed lobar pneumonia in the lungs and hepatocyte necrosis with hepatic cord disintegration in the liver. A strain of Proteus mirabilis (PM2022) was isolated from the affected lungs and liver. This bacterium exhibited multidrug resistance, being susceptible only to cefoxitin and amikacin. Whole-genome sequencing identified 26 antibiotic resistance genes, including CTX-M-65, FosA3, which mediate resistance to five classes of antibiotics, such as penicillins and quinolones. Additionally, 20 virulence factors (including the T6SS secretion system, hemolysins HpmA/B, among others) were detected. Mouse experiments confirmed its high pathogenicity (LD50 = 1.45 × 10⁹ CFU/mL). Based on experimental and genomic testing results, the initial symptoms of Proteus mirabilis infection in pangolins manifest in the lungs, liver, and intestines, and the use of penicillins and quinolones should be avoided during treatment. This study offers clinical guidance for diagnosing and treating P. mirabilis infections in pangolins, informing evidence-based antimicrobial strategies.

The complete chloroplast genome of Glycine tabacina (Labill.) Benth., a perennial legume native to southern China and the Pacific islands, was sequenced for the first time. The circular genome spans 152,842 bp, comprising a large single-copy (83,882 bp), a small single-copy (17,872 bp), and two inverted repeats (25,544 bp). It contains 128 genes, including 83 protein-coding genes. Phylogenetic analysis within the Glycine genus revealed two clusters, with G. tabacina closely related to G. dolichocarpa. This high-quality genome provides a foundation for future phylogenetic and conservation studies of G. tabacina.

Premise Gymnosperms have few mechanisms for shaping the mating pool between the time of pollen reception on a pollination drop (PD) and fertilization. The duration of the PD on the ovule may be one mechanism if it changes depending on relatedness of the pollen source and the recipient. Here, we timed the duration of the PD after pollination with pollen from different clones of the outcrossing conifer Cunninghamia lanceolata . Methods We collected unpollinated strobili from C. lanceolata in the field and grew them hydroponically in a controlled chamber to induce PD production. Using high‐resolution imaging, we monitored PD dynamics in real time after selfed, inbred backcross, and outcross pollination. Interparental genetic distances (GD) were determined for each cross using 21 polymorphic microsatellite loci. Results The high‐resolution imaging revealed that PDs in nonpollinated ovules were exposed for an average of 10.63 ± 1.31 h, whereas PDs in ovules after outcrossing and selfing were withdrawn within 0.46 ± 0.06 h and 3.43 ± 0.84 h, respectively. The three inbred backcrosses were intermediate between selfing and outcrossing. High‐resolution videos further confirmed the withdrawal was rapid and abrupt after outcrossing and slower after most inbred crosses, especially selfing. There was a strong negative correlation between genetic distance and PD withdrawal time ( r = −0.92, P < 0.0001), implying a regulatory mechanism sensitive to the degree of relatedness. Conclusions These novel findings suggest that the longevity of the PD is a mechanism for post‐pollination mate recognition.

In this study, figs were dried by hot air drying (HD), vacuum freeze-drying (FD), vacuum drying (VD) and far-infrared drying (FID). Four fig polysaccharides (FPs) were extracted from different dried figs, and the corresponding names were FPH, FPF, FPV and FPFI. The effects of different drying methods on the structural properties, rheological properties and biological activities of FPs were compared. The result shows that the extraction rate of polysaccharides after FD (2.49%) treatment was 58.60%, 50% and 28.35% higher than that of HD (1.57%), VD (1.66%) and FID (1.94%), respectively. Drying methods result in varying molar ratios of monosaccharides. FPFI has more stable gel properties. HD, VD and FID caused damage to the surface structure of the polysaccharides. FPF exhibited the highest uronic acid content (25.56%), along with relatively low apparent viscosity and molecular weight (1.45 × 10⁵ Da), which contributed to its superior antioxidant and lipid-lowering activities. Therefore, FD is a drying method to obtain fig polysaccharide with high antioxidant and hypolipidemic activity. The results provided a scientific basis for the drying process of fig polysaccharide and a reference for the development of potential hypolipidemic products of fig polysaccharide.

MicroRNAs (miRNAs) control gene expression in plant through transcript cleavage and translation inhibition. Recently, 24‐nt miRNAs have been shown to direct DNA methylation at target sites, regulating the neighboring gene expression. Our study focused on miR9560, a 24‐nt miRNA induced by cadmium (Cd) stress in Brassica rapa ssp. parachinensis (B. parachinensis). Phylogenetic analysis revealed miR9560 predominantly emerged in the Rosanae superorder and was conserved in Brassicaceae, with potential target sites adjacent to transporter family genes HMAs. RNA gel blotting showed that mature miR9560 was only detected in various Brassica crops roots after Cd stress. In B. parachinensis, miR9560's putative target site is upstream of BrpHMA2, an afflux‐type Cd transporter. In a transient expression system of B. parachinensis protoplasts, the expression of miR9560 increased the DNA methylation upstream of BrpHMA2, reducing the transcription of BrpHMA2. This regulation was also observed in Arabidopsis wild‐type protoplasts but not in the mutants dcl234 and ago4 with impairments in the RNA‐dependent DNA methylation (RdDM) pathway. We deduced that miR9560 modulates BrpHMA2 expression via the RdDM pathway, potentially regulating Cd uptake and movement in B. parachinensis. Furthermore, this regulatory mechanism may extend to other Brassica plants. This study enhances our comprehension of 24‐nt miRNAs role in regulating Cd accumulation within Brassica plants.

Introduction Ectomycorrhizal fungus (ECMF) could enhance plant tolerance to heavy metal toxicity by altering metal accumulation and protecting plants from oxidative injury. However, the molecular mechanisms underlying ECMF-mediated detoxification of cadmium (Cd) in willow sapling are not well known. This study aimed to unveil the roles of Cenococcum geophilum (CG) and Suillus luteus (SL) in regulating Cd toxicity tolerance in willow (Salix psammophila ‘Huangpi1’) saplings. Methods This study systematically evaluated physiological and biochemical parameters in the leaf and root tissues of 18 willow saplings, while concurrently conducting transcriptomic analysis of the roots under Cd stress. The specific treatments were labeled as follows: NF (no ECMF inoculation and no Cd addition), CG (CG colonization only), SL (SL colonization only), NF+Cd (no ECMF inoculation with 100 μM Cd addition), CG+Cd (CG colonization with 100 μM Cd addition), and SL+Cd (SL colonization with 100 μM Cd addition). Results The results showed the growth, photosynthesis, antioxidant system and transcriptome of 2-month-old willow saplings responded differently to ECMFs colonization under Cd stress. S. luteus markedly increased the aerial parts biomass, while C. geophilum significantly enhanced the root property indices of willow saplings under Cd stress. The highest number of differentially expressed genes (DEGs) was observed in the comparison between CG+Cd (CG colonization with 100 μM Cd addition) and NF+Cd (no ECMF inoculation with 100 μM Cd addition). C. geophilum colonization activated plant hormone signal transduction and carbohydrate metabolism pathways, while S. luteus enhanced the synthesis of secondary metabolites. Discussion This study provides a molecular perspective on the mechanism of interaction between ECMFs and willow saplings under Cd stress and supports the application of ECMFs for phytoremediation of Cd-contaminated soil.

Due to the strong polarity and volatility of organic acids, there is often a lack of effective quantitative methods for organic acids in vivo or in vitro. This study introduced a robust and scientifically validated LC-MS methodology for quantitatively analyzing six organic acids, encompassing five short-chain fatty acids and lactate, observed in in vitro fermentation and human fecal samples. This method was able to achieve precise quantification through the monitoring of mass-to-charge (m/z) ratios of the deprotonated negative ions. After optimization, a 2:1 (v/v) dichloromethane/acetonitrile mixture was utilized to extract the crude acid mix from fermentation or fecal samples. Subsequently, the organic acids were isolated using 3 mL of 3.5 M ammonium hydroxide solution from mixtures. The calibration curves for six organic acids demonstrated linearity with R² > 0.991 across the concentration ranges of 0.01–5.0 or 0.01–20 mM. The coefficient of variation and accuracy were 2–13% and 95–128%, respectively, which exhibited good precision and sensitivity. Accurate quantification of organic acids would aid in metabolic analysis in bacterial culture supernatants and human fecal matter.

Transposable elements (TEs) are crucial for genome evolution and ecological adaptation, but their dynamics in non-model plants are poorly understood. Using genomic, transcriptomic, and population genomic approaches, we analyzed the TE landscape of Barthea barthei (Melastomataceae), a species distributed across tropical and subtropical southern China. We identified 64,866 TE copies (16.76% of a 235 Mb genome), dominated by Ty3/Gypsy retrotransposons (8.82%) and DNA/Mutator elements (2.7%). A genome-wide analysis revealed 13 TE islands enriched in genes related to photosynthesis, tryptophan metabolism, and stress response. We identified 3859 high-confidence TE insertion polymorphisms (TIPs), including 29 fixed insertions between red and white flower ecotypes, affecting genes involved in cell wall modification, stress response, and secondary metabolism. A transcriptome analysis of the flower buds identified 343 differentially expressed TEs between the ecotypes, 30 of which were near or within differentially expressed genes. The non-random distribution (primarily within 5 kb of genes) and association with adaptive traits suggest a significant role in B. barthei’s successful colonization of diverse habitats. Our findings provide insights into how TEs contribute to plant genome evolution and ecological adaptation in tropical forests, particularly through their influence on regulatory networks governing stress response and development.

The soil microbial community influences and maintains soil quality and health. Leguminous plants are widely used in forestry due to their nitrogen-fixing ability, significantly improving soil quality. However, there are few studies on the effects of woody legumes on soil microbial communities and soil quality. Here, the composition and structure of bulk soil microbial communities associated with six cultivars of Falcataria falcata (L.) Greuter & R. Rankin were analyzed using full-length 16S rRNA sequencing. Additionally, the minimum dataset approach was employed to integrate indexes of soil microbial communities and physicochemical properties, allowing the calculation of a soil quality index to evaluate the cultivars’ soil quality. Although the growth characteristics of the six cultivars were identical, there were significant differences in physiological functions. Notably, cultivar 6 demonstrated a significant advantage over the other cultivars in its overall physiological characteristics. Compared to the control sample, all cultivars clearly improved soil quality, with cultivars 8 and 16 significantly outperforming the others. The findings indicate that the different cultivars improve soil fertility by recruiting microorganisms with specific functions. The stability of soil microbial communities is a crucial biological and ecological factor that influences and sustains soil quality and health and is a key index for the evaluation of these properties.