In order to investigate the enrichment characteristics of heavy metals in soil of different urban-rural environmental gradient zones in Haikou, agricultural surface soil samples were collected from four different urban-rural environmental gradient zones in Haikou, including the urban center, urban-rural transitional zone, rural area, and natural area. The concentration of eight heavy metals were measured, including Cd, Hg, As, Pb, Cr, Cu, Ni, Zn. The enrichment characteristics of heavy metals in soil of Haikou were analyzed through the vertical distribution and migration characteristics of heavy metals, the correlation between heavy metals and physicochemical indicators, and the enrichment coefficient of heavy metals. The results showed that the average contentration of Cd, Pb, and Zn in surface soil was higher than that in deep soil, and heavy metals had varying degrees of cumulative effects. There was a significant positive correlation between soil pH and Cd content, and soil pH had a significant impact on the degree of Cd heavy metal enrichment. Soil organic matter (SOM) was positively correlated with the content of Hg, Cr, Cu, Zn, and Ni. The correlation between layer A and layer B was stronger than that of layer C. Surface soil SOM had a significant impact on heavy metal enrichment. The proportion of sites with heavy metal enrichment coefficients greater than 1.2 ranged from high to low was Cd (70.0%), Hg (41.7%), As (36.7%), Pb (28.3%), Zn (21.7%), Cu (18.3%), Ni (18.3%), and Cr (15.0%). The enrichment degree of heavy metals in agricultural land soil in Haikou showed a certain distance gradient variation feature, with the increase of distance from the urban center, the enrichment degree of eight soil heavy metals showed a gradually decreasing trend. Only Cd showed enrichment in the natural area, and no enrichment points were found for the other 7 heavy metals. The enrichment coefficients of Cd, Hg, and As soil heavy metals involved a wide range. The points with enrichment coefficients greater than 8 for Cd in urban central areas far exceeded that in urban-rural and rural areas. The points with enrichment coefficients greater than 2 for Hg were only located in urban central areas and urban-rural transitional areas. The proportion of points with Cd enrichment coefficients greater than 1.2 far exceeded the other seven heavy metal projects. The coverage of Cd enrichment in urban and rural environmental gradients was the highest, and the regional enrichment characteristics were obvious. In addition, the enrichment coefficient of 30% Cd points was greater than 4, indicating a strong soil Cd enrichment degree, which should be paid attention to.

This study explored the spatial patterns of land use and the driving forces affecting the rural community in Hainan Tropical Rainforest National Park. It focused on three representative rural communities: Maoyang Township, Nankai Township, and Shuiman Township. Utilizing remote sensing images from 2000, 2010, 2018, and 2023, we analyzed the evolution of land use in the communities from 2000 to 2023 through a comprehensive approach including land use transfer matrices, a comprehensive index of land use degree, landscape pattern indices, and geodetector analysis. Forest land constituted the primary land use type in the rural communities, with the area of forest land increasing from 2000 to 2018 and decreasing from 2018 to 2023. In contrast, cultivated land initially decreased (2000—2018) before experiencing an increase (2018—2023). The land use changes in the communities can be categorized into two phases, the conversion of farmland to forest (2000—2018) and the conversion of forest land to cropland and construction land (2018—2023). Changes in land use types primarily drived changes in the landscape patterns of the rural communities. The landscape characteristics reflect reduced aggregation, increased fragmentation, and enhanced diversity of landscape types. Spatially, the fragmentation of the landscape exhibited a high central area surrounded by lower-density regions. The land use change in the typical rural community of Hainan Tropical Rainforest National Park were influenced by policy and human factors. The normalized difference vegetation index and proximity to roads were consistently identified as significant influences on land use changes. At the same time, the digital elevation model also played a significant role. Interaction detection results revealed that the relationships among the factors displayed either two-factor enhancement or non-linear enhancement, with the explanatory power of two-factor interactions surpassing that of individual factors. This study aims to offer recommendations for the sustainable construction and development of rural communities within national parks.

Dendrobium nobile has a high ornamental value and is one of the important parental plants in the hybridization group of Dendrobium. To explore the physiological and molecular mechanisms of D. nobile flowers in response to high-temperature stress, this study combined water potential, cell membrane permeability monitoring, ethylene-related compound content determination, and transcriptome analysis. Treatment groups were subjected to 36 ℃ high-temperature stress for 5 h, 10 h and 24 h, with a normal temperature culture as the control. The physiological characteristics of D. nobile flowers under 36 ℃ and the transcriptome response to high temperature were studied. The results shoed that 36 ℃ high-temperature stress had almost no effect on the water status and cell membrane permeability of D. nobile flowers within 24h. The content of ethylene precursor (ACC) in the flowers significantly increased in all three high-temperature treatment groups compared to the control (Dno-CK). The number of differentially expressed genes between the 5 h high-temperature treatment and the control group (Dno-CK vs Dno-5h), the 10 h high-temperature treatment and the control (Dno-CK vs Dno-10h), and the 24 h high-temperature treatment and the control (Dno-CK vs Dno-24h) was 25 204, 25 528 and 26 878, respectively, with the number of genes up-and downregulated was approximately 1∶1. As the duration of high-temperature stress increased, the total number of differentially expressed genes in D. nobile flowers gradually rose. KEGG enrichment analysis showed that the differential genes of the three comparison groups were enriched to the monoterpene biosynthesis pathway, indicating that high temperature promoted the synthesis of volatile terpenoids in D. nobile. Functional enrichment analysis indicated that most of the differentially ex-pressed genes in response to high-temperature stress were enriched in pathways related to genetic information processing and metabolic pathways, with the highest number of differential genes in the nucleotide excision repair, starch and sucrose metabolism, and protein processing in the endoplasmic reticulum pathways. This suggests that high temperature stimulates D. nobile flowers to enhance various metabolic activities in response to heat stress. Screening of differentially expressed genes revealed that heat shock protein (HSP) genes in D. nobile flowers were significantly up-regulated in response to high-temperature stress. The HSP genes responding to high-temperature stress within 24 h in D. nobile flowers were primarily the HSP20 genes, followed by the HSP90 genes. Further research on the heat re-sponse genes of D. nobile flowers can focus on the HSP20 and HSP90 genes. This study on the physiological and transcriptome response of D. nobile flowers to high-temperature stress would provide a reference for heat-tolerant breeding research and theoretical support for the cultivation of heat-resistant D. varieties.

Hongyang kiwifruit is a distinguished variety independently developed in China. It features a distinctive red coloration, possesses high sugar content and low acidity, and is favored for its rich aroma and unique flavor profile. The growth and development of fruits are influenced by a multitude of factors, among which sucrose non-fermentation-1-associated protein kinase 1 (SnRK1) plays a pivotal role in the regulation of carbohydrate metabolism and the response to both biotic and abiotic stresses. Therefore, in this study, we cloned the full-length cDNA of 2 genes in the SnRK1 family of Hongyang kiwifruit, named AcSnRK1.1 and AcSnRK1.2. The physical and chemical properties, gene structure, conserved motifs, protein conserved domains, and cis-acting elements of AcSnRK1.1 and AcSnRK1.2 were systematically analyzed using bioinformatics approaches. The expression characteristics of AcSnRK1.1 and AcSnRK1.2 genes in different tissues and fruits were quantitatively detected by real-time fluorescence. AcSnRK1.1 and AcSnRK1.2 genes contained an open reading frame of 1548 bp and 1545 bp, respectively, encoding proteins containing 515 and 514 amino acids with highly consistent sequences (96.31%) respectively. Both genes contained 10 exons and 2 introns. Bioinformatics analysis showed that AcSnRK1.1 and AcSnRK1.2 had high homology with other plant SnRK1 proteins. The amino acid sequence showed that STKc_AMPK_alpha, AMPK_C and UBA_SnRK1_plant were unique to the SnRK1 family. Evolutionary tree analysis showed that AcSnRK1.1 and AcSnRK1.2 belonged to the SnRK1 family. Tissue specific analysis showed that AcSnRK1.1 and AcSnRK1.2 were expressed in all tissues of Hongyang Kiwifruit, but the expression abundance was the highest in fruit. During fruit development, the expression levels of AcSnRK1.1 and AcSnRK1.2 decreased first and then increased. qRT-PCR analysis showed that the expression of AcSnRK1.1 and AcSnRK1.2 was responsive to ABA, GA₃, ET and CPPU. With the increase of storage time, the expression levels of AcSnRK1.1 and AcSnRK1.2 showed a downward trend first and then an upward trend, suggesting that AcSnRK1 gene might regulate the expression of sucrose synthase. The results of this study indicate that AcSnRK1.1 and AcSnRK1.2 genes play an important role in the development and storage of Hongyang kiwifruit, which would lay a foundation for further elucidation of the functions of AcSnRK1.1 and AcSnRK1.2 genes.

Vanda coerulea, an epiphytic plant with bare roots growing in air, has important value for orchid breeding and ornament. Exploring the development and defense mechanism of the aerial roots from the omics level can provide a theoretical basis for comprehensive understanding of the unique adaptation mechanism of aerial roots. In this study, we used three root sites with different developmental levels of V. coerulea aerial roots as materials, combined with transcriptomics and metabolomics, to reveal the development of different parts of V. coerulea roots and the defense mechanisms. Transcription-metabolism analysis showed that the differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs) were significantly enriched in the metabolic pathway, biosynthesis pathway of various secondary metabolites and pathway of plant hormone signaling in two comparison groups. Transcriptome analysis showed 11 995 DEGs between the meristematic (group A) and elongation (group B) zones of the root, with 6274 up-regulated and 5721 down-regulated. There were 3673 DEGs between the elongation (group B) and maturation zone (group C) of the root, with 1691 up-regulated and 1982 down-regulated. Metabolomic results revealed 102 DAMs between the two comparison groups, with 52 up-regulated and 50 down-regulated. In the development of roots, the relative expression levels of growth regulators such as auxin, gibberellins (GAs) and abscisic acid (ABA) had significant changes in different developmental stages of plant roots. In terms of defense mechanism, the genes related to the synthesis of alkaloids, flavonoids, and lignins were more expressed in the meristem and elongation zone of roots than in the mature zone. The results indicate that aerial roots development under the regulation of the above-mentioned hormones and accumulate a variety of secondary metabolites to improve defensive capabilities.

ELF3 is an important biological clock gene that regulates the input of light signal and the output of circadian rhythm, participating in modulation of many important processes of plants. In order to understand its regulation in the initiation of petal senescence of Oncidium, we conducted cloning and expression analysis of OnELF3 in Oncidium.OnELF3 (GenBank accession number: OL613896) was isolated from the Oncidium petals. OnELF3 had a length of 2208 bp and encoded a protein of 735 amino acids. Subcellular localization showed its expression in the nucleus. Homologous sequence alignment and phylogenetic tree analysis showed that OnELF3 was closest to the counterparts of Dendrobium candidum and Phalaenopsis. Prokaryotic expression analysis showed that the cloned OnELF3 was capable of prokaryotic expression of functional proteins. Its expression patterns under long day, full light, and full darkness conditions were consistent with its function as a circadian clock gene. Real time fluorescence quantitative analysis showed that the expression of OnELF3 was the highest in cracked buds and full-open flowers, indicating that OnELF3 may play a role in both flowering and flower senescence initiation. This study would lay a foundation for further functional identification of OnELF3 in the initiation of flower senescence.

The unique charm and graceful appearance of bamboo align with traditional Chinese aesthetic preferences and moral consciousness. Additionally, due to its rapid growth, diverse species, and strong adaptability, bamboo has been an important element in environmental construction in China since ancient times. This study employed the line transect method to conduct on-site investigations and data collection in 44 urban parks in Fuzhou, exploring the application of bamboo plants and the characteristics of bamboo landscape construction in Fuzhou’s urban parks. The aim was to provide theoretical and practical guidance for improving the environmental quality of urban parks. The results showed that among the 44 urban parks, there were 38 varieties of bamboo plants across 12 genera (including species, varietas, forma and cultivarietas), with 15 varieties from the genus Bambusa, 8 varieties from the genus Phyllostachys and 2 varieties from the genus Dendrocalamus being used more frequently. The most commonly used bamboo plants were P. iridescens, P. glauca, and D. latiflorus. In different types of bamboo landscapes, the proportion of bamboo resources applied to bamboo with other plants and bamboo with environmental furniture exceeded 70%, followed by bamboo with architecture and bamboo with pavement. The application of bamboo resources accounted for 63% and 55%. The application proportion was the lowest in bamboo with terrain and bamboo with water landscapes, accounting for 45% and 32%. In all types of bamboo landscapes, the frequency of single bamboo resource application was below 30%. The quantitative distribution of bamboo landscapes in Fuzhou’s urban parks generally showed higher concentrations in the city center and lower in the surrounding areas. The application of bamboo landscapes was concentrated in traditional Chinese garden styles and larger urban parks built around the year 2000. Among bamboo landscape applications, bamboo with other plants ranked the highest with 154 instances, followed by bamboo with architecture (140 instances), bamboo with environmental furniture (109 instances), bamboo with pavement (103 instances), and the least were bamboo with terrain (46 instances) and bamboo with water (42 instances). Bamboo with other plants and bamboo with architecture were distributed across 34 parks, making them the most widespread. Following were bamboo with environmental furniture and bamboo with pavement, found in 32 and 27 parks, respectively. The least widespread were bamboo with terrain and bamboo with water, located in 16 and 11 parks, respectively. Except for Chating Park and Yushan Scenic and Historic Park, the overall distribution density of bamboo landscapes in Fuzhou’s urban parks was relatively low, with bamboo landscape nodes being scattered. The application of bamboo plants and the construction of bamboo landscapes in urban parks were still at a relatively low level. In future urban park construction, systematic planning should be strengthened, the diversity of ornamental bamboo plants should be increased, and emphasis should be placed on the characteristics of the parks to comprehensively improve the environmental quality of urban parks.

This paper aimed to explore the arbuscular mycorrhizal (AM) fungal community structure in the rhizosphere soil of ratoon sugarcane in the second year under different fertilization levels, and provide a theoretical basis for the application of AM fungi in sugarcane. In this study, sugarcane varieties GT29 and GT58 were used as the materials. Four fertilization levels were set: 0.0 kg/hm² (A), 562.5 kg/hm² (B), 1125.0 kg/hm² (C), 2250.0 kg/hm²(D). The results showed that different fertilization levels had significant effects on the root mycorrhizal infection rate of GT29, but had no significant effect on GT58. With the increase of fertilization level, the diversity and richness of AM fungi decreased significantly. With the increase of fertilization level, the diversity and richness of AM fungi decreased significantly. A total of 185 AM fungi OTUs were detected in GT29 and 175 in GT58. The dominant AM fungi in the rhizosphere soil of the two varieties under different fertilization levels were Glomus. The species diversity of AM fungal community in rhizosphere soil under different fertilization levels was analyzed at the OTU level. It was found that the two species of GT29 belonged to the genus Glomus, while the three species of GT58 belonged to the genus Claroidoglomus. Mantel test showed that the contents of Ca and Mg in soil were significantly positively correlated with the four genera, and the soil pH was also significantly positively correlated with the three genera. Therefore, excessive fertilization will significantly reduce the yield increase effect, cause soil acidification and excess phosphorus, and change the composition, diversity and richness of AM fungi community in sugarcane rhizosphere soil, but the varieties are different; Proper fertilization was helpful to enrich the diversity of soil AM fungi and promote the sustainable development of sugarcane yield.

Cymbidium ‘Shuangyi Jinlong’ is a new variety selected and bred from the clonal variation of the hybrid orchid cultivar ‘Golden dragon’ by Fujian Bainong Ecological Technology Co. Ltd.. It integrates flower and leaf art, has good germination, easy flowering and strong resistance, and has a high market demand. The rhizome and tissue culture seedlings of Cymbidium ‘Shuangyi Jinlong’ were used as experimental materials, and the orthogonal experiment was conducted to optimize the influencing factors of rhizome proliferation and differentiation, rooting and seedling growth, seedling cultivation and transplanting, in order to improve the seedling reproductive efficiency and seedling quality of hybrid orchid, and establish a standardized production system. The most suitable medium for rhizome proliferation and growth was MS medium supplemented with 1.00 mg/L NAA, 0.10 mg/L 6-BA, 20.00 g/L sucrose, 1.00 g/L activated carbon, 6.30 g/L agar, and 1.00 g/L peptone; the quantity value-added coefficient was determined to be 3.57 while the quality value-added coefficient was found to be 4.63. The optimal medium for rhizome differentiation was 1/2MS,1.50 mg/L NAA, 0.90 mg/L TDZ, 100.00 g/L banana homogenate, 25.00 g/L sucrose 6.30g/L; the leaf bud differentiation rate reached up to 97.78%, with a differentiation coefficient of 6.87. The best-performing medium for rooting and seedlings strengthening was 1/2MS, l.00 mg/L IBA, 100.00 g/L banana homogenate, 0.17 g/L KH₂PO₄, 30.00 g/L sucrose, agar and l.00 g/L activated carbon. After 90 days of cultivation, the average number of roots per plant was five, with a root length of 5.40 cm, a pseudobulb thickness of 4.35 mm, a plant height of 12.95 cm, and a fresh quality of 2.42 g. The recommended method for transplanting tissue culture seedlings involves using water hyacinth∶pine bark (V∶V=1∶1) as the transplantation substrate after 21 days in vitro culture. The survival rate after 60 days post-transplantation reached 83.33%. Taking into account the impact of various factors, this study ultimately identified the optimal medium compositions at each stage and refined transplanting schemes. This provides a reference for establishing a standardized production system.

Beta-ketoacyl-acyl carrier protein synthase (KAS) is the key enzyme system in plant fatty acid biosynthesis. In order to investigate the function of the KAS gene family in the maturation and oil accumulation of Camellia oleifera, this study used bioinformatics methods and analyzed ther physicochemical properties, chromosomal localization, subcellular localization, secondary structure, phylogenetic trees, conserved motifs, promoter cis-acting elements, and RT-qPCR to analyze the expression patterns in the oil rapid accumulation stage of C. oleifera. The findings indicated that 14 Camellia oleifera KAS family members were distributed on seven chromosomes with relative molecular masses between 1.13 kDa and 5.15 kDa, and most of them were acid-stabilized proteins. Except for CoKAS II-2, which was localized in mitochondria and chloroplasts, all of them were localized in chloroplasts. Phylogenetic analysis revealed that CoKAS was divided into three subclasses, with similarities in structure and conserved motifs among KAS family numbers in the same subfamily. The promoter regions of the CoKAS gene family members were enriched with the cis-acting elements growth and development-related, light response, hormone induction, and adversity response. Expression analysis revealed that most of the CoKAS genes were highly expressed during the oil rapid accumulation stage. In addition, it was found a strong correlation between the members of the CoKAS and CoMYB gene families during fruit ripening in C. oleifera. The findings would provide a theoretical basis for comprehensively analyzing the function of CoKAS genes.