Guizhou Research Articles

Spatiotemporal characteristics and driving mechanisms of land-use transitions and landscape patterns in response to ecological restoration projects: A case study of mountainous areas in Guizhou, Southwest China

With the acceleration of urbanization and industrialization, the land-use mode in mountainous areas has changed significantly, causing serious ecological destruction. Therefore, improving the efficiency of land-resource use in mountainous areas and enhancing ecological protection are important issues. This study focuses on typical mountainous areas in Guizhou Province to explore their significance not only for ecological restoration but also for sustainable socioeconomic development. In this study, we integrated the framework of the interaction between land-use transitions and landscape patterns and employed Spearman's rank correlation coefficient and a spatial bivariate model to reveal the spatiotemporal heterogeneity of landscape patterns and land-use transitions. The results showed that for 1990–2020, the cultivated, forest, and grassland areas decreased by −1353.66, −749.98 and − 541.72 km2 respectively, whereas the water area, urban, and other construction land increased by 799.69, 542.62, and 1230.90 km2, respectively. Moreover, the cultivated land areas converted into urban and other construction land were 358.03 and 661.77 km2 respectively, and the grassland areas converted into forest and other construction land were 3550.08 and 277.32 km2, respectively. Different land-use transitions presented rapid expansion and contraction characteristics, resulting in an increase in overall patch fragmentation, a decrease in uniformity, and an increase in irregular patches, which enhanced the spatial heterogeneity of diversity and complexity. Finally, the land-use transition effects on landscape patterns were primarily elevation, slope, and primary road facility factors. In-depth research on land-use transitional evolution and its impact on landscape patterns has important theoretical and practical value for formulating land-management policies and promoting sustainable development in mountainous areas.

Biological Characteristics, Artificial Domestication Conditions Optimization, and Bioactive Components of Beauveria caledonica.

In this study, one strain of Beauveria caledonica was isolated from wild fruiting bodies collected from Guizhou Province, China, and its species identification, biological characteristics, domestication, and cultivation methods were studied along with polysaccharide and adenosine content analysis. The mycelia were identified by ITS sequencing, and the fruiting bodies of B. caledonica were domestically cultivated for the first time using wheat and rice as basic cultivation media. The carbon sources, nitrogen sources, cultivation temperatures, and pH for mycelial growth were optimized through single-factor experiments and response surface methodology (RSM) experiments. The polysaccharide content was detected by the phenol-sulfuric acid method, and the adenosine content was measured by high-performance liquid chromatography (HPLC). The results confirmed that the identified mycelia were B. caledonica. The optimum medium for solid culture was 25.8 g/L glycerol, 10.9 g/L yeast extract, 1 g/L MgSO4·7H2O, 1 g/L KH2PO4, 10 mg/L vitamin B1, and 20 g/L agar; the optimum pH was 6.5, and the optimum culture temperature was 25 °C. The optimal liquid culture medium was 26.2 g/L glycerol, 11.1 g/L yeast extract, 1 g/L MgSO4·7H2O, 1 g/L KH2PO4, and 10 mg/L vitamin B1; the mycelia grew well at pH 6.6 and 25 °C. The average biological efficiencies of fruiting bodies on wheat and rice as culture media were 1.880% and 2.115%, respectively; the polysaccharide contents of fruiting bodies on the two media were 6.635% and 9.264%, respectively, while the adenosine contents were 0.145% and 0.150%, respectively. This study provides a valuable reference for further artificial cultivation and utilization of B. caledonica by investigating its biological characteristics, cultivation conditions for artificial domestication, and polysaccharide and adenosine contents in cultivated fruiting bodies.

The nexus between visitor satisfaction and expenditure behaviour in national parks: The case of Dragon Palace National Park, Guizhou, China

Several studies have explored the relationship between visitor expenditure, experience, satisfaction, intention to recommend, and revisit intention in national parks, but there is a gap in exploring the direct relationship between satisfaction and expenditure of national park visitors. This research identifies relationships between expenditure and behaviour patterns in Dragon Palace National Park, a 5A visitor attraction in Guizhou province, China. A structured survey questionnaire was utilised to collect 412 responses from national park visitors, employing convenience sampling techniques from August to December 2022. A partial least squares-structure equation model 4.0 was used to analyse the data. Findings support the positive relationship between experience, satisfaction, intention to recommend, and revisit intention in the national park. Also, results confirm that rational and emotional dimensions effectively measure the experience level. Further, this research confirms that experience is not a predictor of expenditure and that satisfaction has a negative relationship with expenditure by providing a measurement model to examine the experience in the national park. It frames a new theoretical lens on the relationship between expenditure and satisfaction and contributes significance to national park operations, providing a reference for future research. Management implicationsThe negative relationship between satisfaction and expenditure is interesting. The continuance of fostering national park visitor satisfaction for tourists cannot make sense to improve expenditure. The Dragon Palace National Park should pay more attention to overnight visitors' satisfaction and expenditure since they spend more but are less satisfied. It is vital to enhance the consuming willingness of visitors, improving the expenditure of satisfied visitors. Customising the experience, improving the cost performance of various goods and services, and enriching the experience content may work. The dimensions of the experience have been tested as effective, and the measurement model can be applied in other national parks.

Identification, Pathogenicity, and Fungicide Sensitivity of Colletotrichum Species Associated with Anthracnose on Italian Ryegrass in Southwestern China.

Italian ryegrass (Lolium multiflorum L.) is widely cultivated as an important forage worldwide because of its high nutritional value and good palatability. Anthracnose caused by Colletotrichum species was a common and new emerging disease of Italian ryegrass. In this study, 88 Colletotrichum isolates were collected from diseased leaves of Italian ryegrass planting regions in Sichuan, Chongqing and Guizhou provinces of southwestern China between 2019 and 2022. By pure culture technique, 15 representative single-spore isolates were obtained for further study. Multi-locus phylogenetic analysis coupled with morphological features showed that these isolates were finally identified as six new record species: C. cereale of the C. graminicola species complex, C. fioriniae and C. nymphaeae of the C. acutatum species complex, C. boninense and C. citricola of the C. boninense species complex, and C. nageiae. Pathogenicity tests indicated that all species could induce anthracnose symptoms; of these, C. cereale was more invasive than other species, followed by C. fioriniae, C. nageiae, C. citricola and C. boninense; C. nymphaeae was weakest pathogenic to Italian ryegrass plants (P ≤ 0.05). Fungicide sensitivity assays showed that iprodione, propineb and oxime·tebuconazole had strong inhibitory effect on the mycelial growth of six Colletotrichum species; in addition, azoxystrobin and fludioxonil also significantly inhibited the mycelial growth of C. nymphaeae and C. fioriniae, respectively. These results provide the basis for the diagnosis and detection in the field, pathogen identification and management of anthracnose on Italian ryegrass.

Pestalotiopsis kenyana causes leaf spot disease on Rhododendron agastum in China

Rhododendron agastum, a well-known flower with significant aesthetic and medicinal value, belongs to the Rhododendron genus in the Ericaceae family. In April 2023, a leaf spot disease on R. agastum plants was found in the Baili Azalea Forest Area in Guizhou province, China. Approximately 400 plants were surveyed, and the incidence of leaf spot on R. agastum leaves was 20%. The damaged leaves had gray-white irregular diseased spots with black-brown margins and black conidiomata on the surface of the spots. When the disease is severe, the leaves fall. Leaf spot disease is a serious problem for rhododendrons, reducing their ornamental value and causing significant economic losses. To identify the pathogen, we conducted pathogen isolation and pathogenicity study. The pathogen was identified as Pestalotiopsis kenyana by morphological features and combined analysis of multiple genes (ITS, tef1-α, and Tub2). Koch's postulates was tested by isolating and reidentifying the pathogen from inoculated plants, showing that P. kenyana was the causative agent of the disease. To our knowledge, this is the first report of P. kenyana causing leaf spot in R. agastum. This study gives important information for the identification and control of the leaf spot disease caused by P. kenyana.

Distinguishing urban-rural difference in Chinese population exposure to ambient air pollutants

Using outdoor concentrations as surrogates of human exposure to ambient air pollutants introduces significant errors, as people spend the majority of their lives indoors. The infiltration factor and exposure factor are widely employed to modify outdoor-originated air pollution exposure. However, previous studies of the Chinese population lacked sufficient data on rural residents, limiting the representativeness and accuracy of the results. Here, we modeled the infiltration factor and exposure factor of five ambient air pollutants (NO2, SO2, O3, PM2.5 and PM10) in both rural and urban areas across 31 Chinese provinces and conducted field experiments in Beijing, Yunnan, Guizhou and Sichuan Provinces for 8 months to validate the modeling results. The infiltration factor and exposure factor vary between different air pollutants, with the exposure factor of PM2.5 reaching 70% for rural residents. Additionally, we found significant regional, seasonal, gender, and age differences between the urban and rural modification factors: infiltration and exposure factors in rural areas are generally greater than those in urban areas, especially in Northeast China; and the urban‒rural exposure disparity is most pronounced during winter, with a relative difference of up to 28% for SO2. The results are expected to be applied to modify population exposure to ambient air pollutants among Chinese urban and rural residents, promote accurate estimations of population health risks and further contribute to the implementation of targeted interventions.

First Report of Leaf Blight of Osmanthus fragrans Caused by Diaporthe eres in China.

Osmanthus fragrans is an evergreen garden tree species, with high ecological, social, and economic benefits (Lan et al. 2023), which is widely planted in Guizhou Province. From late April to June 2023, a leaf blight disease was observed on O. fragrans in a bauxite mining area in Qingzhen City, with an incidence of ~50%. Symptoms first appeared at the leaf tip or margin, as irregular brown spots, which gradually coalesced into dark brown patches until the leaves withered and fell off. Symptomatic leaves were collected and surface disinfected with 2% NaClO for 30 s, 75% ethanol for 30 s, rinsed 3 times in sterile ddH2O, air-dried and placed on potato dextrose agar (PDA) medium and incubated at 25°C for 7 d. Fungal colonies on PDA of 9 similar obtained isolates were white, with at least one concentric ring. The reverse was light yellow and gradually turned brown. At 12 d, the pycnidia on PDA was gray to black, spherical or conical, with a diameter of 305.15 μm (n=20). The conidial horns oozed out from pycnidia after 25 d of incubation on Pinus massoniana needles. The alpha conidia were unicellular, fusiform, hyaline, had a guttule at each end, and measured 6.24 ± 0.10 μm × 2.48 ± 0.04 μm (n=50). No beta or gamma conidia were observed. The morphological characteristics were likely to Diaporthe spp. (Gomes et al. 2013). DNA of isolates GH02, GH06 and GH08 was extracted. The internal transcribed spacer region (ITS) and partial sequences of translation elongation factor 1-alpha (TEF1-α), calmodulin (CAL), beta-tubulin (TUB2), and histone H3 (HIS) genes were amplified with primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R, CAL228F/CAL737R (Carbone and Kohn, 1999), βt2a/βt2b and CYLH3F/H3-1b (Crous et al. 2004; Glass and Donaldson, 1995), respectively. The sequences of ITS, TEF-1α, TUB2, CAL and HIS were deposited in GenBank (GH02: PP813499, PP813844, PP813846, PP813848 and PP813850; GH06: PP813500, PP813845, PP813847, PP813849 and PP813851; GH08: PP507168 and PP529956 to PP529959). BLAST results showed the sequences of GH08 were highly identical to sequences of Phomopsis mahothocarpi (NR147522 [ITS], 527/530), P. mahothocarpi (MW700277 [TEF-1α], 367/372), D. eres (OR885862 [TUB], 513/513), D. celeris (ON221721 [CAL], 484/486), and D. eres (OP968956 [HIS], 477/477). A phylogenetic tree constructed with MEGA X using Neighbor-Joining algorithm (Felsenstein, 1985) indicated the isolate GH02, GH06 and GH08 separated from D. eres CBS 297.77 previously reported from O. aquifolium in Netherlands, as well as D. osmanthi and D. fusicola from O. fragrans in China (Gomes et al. 2013; Long et al. 2019; Si et al. 2021). Based on these results, the three isolates were identified as D. eres (Chaisiri et al., 2021). The isolate GH08 was deposited in the Forest Protection Laboratory, Guizhou University. To confirm pathogenicity, spore suspensions (1×105 spores/mL) of GH08 were sprayed on healthy detached leaves (n=10) and leaves of 3-year-old potted O. fragrans seedlings (n=8). An equal volume of sterile water was sprayed for the control. Then they were placed at 20°C and 70-80% RH. Similar leaf blight symptoms appeared after 5 and 15d on the inoculated leaves and seedlings, respectively. The re-isolated fungus, was identical to D. eres based on morphological and molecular analysis, thus fulfilling Koch's postulates. To our knowledge, this is the first report of D. eres causing leaf blight of O. fragrans in China, supporting a basis for developing effective methods to manage this disease.

Prediction of Chinese suitable habitats of Panax notoginseng under climate change based on MaxEnt and chemometric methods

Notoginseng saponin R1; ginsenosides Rg1, Re, Rb1, and Rd; the sum of the five saponins; and underground-part fresh weight (UPFW) of single plants were used as quality evaluation indices for Panax notoginseng (Burk.) F. H. Chen (P. notoginseng). Comprehensive evaluation of P. notoginseng samples from 30 production areas was performed using that MaxEnt model. Spatial pattern changes in suitable P. notoginseng habitats were predicted for current and future periods (2050s, 2070s, and 2090s) using SSP126 and SSP585 models. The results revealed that temperature, precipitation, and solar radiation were important environmental variables. Suitable habitats were located mainly in Yunnan, Guizhou, and Sichuan Provinces. The distribution core of P. notoginseng is predicted to shift southeast in the future. The saponin content decreased from the southeast to the northwest of Yunnan Province, which was contrary to the UPFW trend. This study provides the necessary information for the protection and sustainable utilization of P. notoginseng resources, and a theoretical reference for its application in the quality evaluation of Chinese medicinal products.

Stenoxylitaquadrifasciata sp. nov. (Coleoptera, Melandryidae) from Guizhou, southwest China.

The genus Stenoxylita Nomura, 1959 (Coleoptera, Melandryidae) currently contains two species, Stenoxylitatrialbofasciata (Hayashi & Katö, 1956) from Japan and Shaanxi, China (Konvička 2015) and Stenoxylitasasajii Toyoshima, 2001 from North Vietnam. We discovered a new species of the genus from the Mountain Leigong of Guizhou Province, China. A new species, Stenoxylitaquadrifasciata sp. nov., is described from Mountain Leigong, Leishan County, Guizhou Province of southwest China. It is the third species of this genus and the second species of this genus from mainland China.

Low-Temperature Regulates the Cell Structure and Chlorophyll in Addition to Cellulose Metabolism of Postharvest Red Toona sinensis Buds across Different Seasons.

Postharvest fibrosis and greening of Toona sinensis buds significantly affect their quality during storage. This study aimed to clarify the effects of low-temperature storage on postharvest red TSB quality harvested in different seasons. Red TSB samples were collected from Guizhou province, China, 21 days after the beginning of spring (Lichun), summer (Lixia), and autumn (Liqiu), and stored at 4 °C in dark conditions. We compared and analyzed the appearance, microstructure, chlorophyll and cellulose content, and expression levels of related genes across different seasons. The results indicated that TSB harvested in spring had a bright, purple-red color, whereas those harvested in summer and autumn were green. All samples lost water and darkened after 1 day of storage. Severe greening occurred in spring-harvested TSB within 3 days, a phenomenon not observed in summer and autumn samples. Microstructural analysis revealed that the cells in the palisade and spongy tissues of spring and autumn TSB settled closely during storage, while summer TSB cells remained loosely aligned. Xylem cells were smallest in spring-harvested TSB and largest in autumn. Prolonged storage led to thickening of the secondary cell walls and pith cell autolysis in the petioles, enlarging the cavity area. Chlorophyll content was higher in leaves than in petioles, while cellulose content was lower in petioles across all seasons. Both chlorophyll and cellulose content increased with storage time. Gene expression analysis showed season-dependent variations and significant increases in the expression of over half of the chlorophyll-related and cellulose-related genes during refrigeration, correlating with the observed changes in chlorophyll and cellulose content. This research provides valuable insights for improving postharvest storage and freshness preservation strategies for red TSB across different seasons.

Relationships among perceived social support, mindful self-care, and resilience among a sample of nurses in three provinces in China: a cross-sectional study.

In this study, we aimed to determine the relationships among perceived social support, mindful self-care, and resilience in a sample of nurses in three provinces of China. A cross-sectional study was conducted in seven hospitals in Guangdong, Guizhou, and Henan provinces between August and October, 2023; the provinces are located in south, southwest, and central China. A total of 389 nurses were surveyed using a self-designed sociodemographic characteristics questionnaire and the Chinese versions of Multidimensional Scale of the Perceived Social Support, Brief-Mindful Self-Care Scale and the 10-item Connor-Davidson Resilience Scale (CD-RISC-10). Of the 389 nurses, the majority were women (n = 365; 93.8%), aged 26-35 years (n = 244; 62.7%) and had bachelor's degrees (n = 337; 86.6%), had worked for 10-20 years (n = 136; 35%), with junior professional titles (n = 331; 85.1%), and had a monthly income in the range 3,001-6,000 yuan in CNY (n = 239; 61.4%). Nurses' resilience was measured using the CD-RISC-10, which ranges from 10 to 40 points. And average score of nurses' resilience was (23.94 ± 6.95). Multiple linear regression showed that scores for resilience were higher among nurses who had higher educational attainment (95% confidence interval: 0.568-3.024, p < 0.01), professional titles (95% confidence interval: 0.009-1.693, p < 0.05), scores of mindful self-care (95% confidence interval: 0.086-0.155, p < 0.01), and scores of perceived social support (95% confidence interval: 0.242-0.328, p < 0.01). Nurses with higher educational attainment and professional titles exhibited higher levels of resilience. Perceived social support and mindfulness self-care are significantly positively correlated with resilience of nurses. The findings of this study are beneficial to further our understanding of nurses' resilience. The identification of associated factors is conducive to providing more support for nurses who tend to have lower resilience earlier, and can provide useful information for research targeted intervention and support plans aimed at improving nurses' resilience in the future.

A serial mediation model reveals the association between parental over-protection and academic entitlement among nursing students

The study aims to explore the influence of parental over-protection on academic entitlement of nursing students, and examine the mediating roles of external locus of control and psychological entitlement. The study sampled two medical universities in Guizhou and Yunnan provinces, China. Participants were nursing students in grades one to four (N = 1003; mean age = 19.51 years; 81.95% female). Using a structural equation model, we examined the mediating effect of external locus of control and psychological entitlement on parental over-protection and academic entitlement. The results show that there was a significant correlation between all variables, and external locus of control and psychological entitlement played a serial mediating role between parental over-protection and academic entitlement. Our findings suggest that academic entitlement of nursing students can be reduced by adjusting parental rearing behaviors, reducing students’ psychological entitlement, and teaching them how to form a healthier attribution style.

Differences in Soil Fertility and Bacterial Community Structure Between Carbon Inputs such as Biochar and Organic Fertilizer and Their Relationship

The potato planting area of Guizhou Province ranks second in China. However, due to factors such as climatic conditions and unbalanced fertilization, soil organic matter in potato fields is consumed rapidly and has a large deficit, which affects soil biological function and soil fertility. Biochar and organic fertilizer are effective ways to supplement foreign aid organic matter to improve soil quality. However, the differences in soil fertility and microbial community structure and their relationships under the conditions of organic fertilizer or biochar combined with chemical fertilizer are not clear. In this study, three treatments of conventional fertilization （NPK）, increased application of biochar （NPKB）, and increased application of organic fertilizer （NPKO） were set up to investigate the characteristics of potato rhizosphere soil, bacterial community composition, and diversity； to analyze the effects of these factors on the soil integrated fertility index； and to explore the direct and indirect effects of IFI on soil fertility and bacterial community structure differences between treatments and their driving factors. The results showed that soil pH, available phosphorus （AP）, available potassium （AK）, total nitrogen （TN）, organic carbon （SOC）, and C/N ratio were significantly higher in the NPKB and NPKO treatments than in the NPK treatment （P<0.05）. Soil IFI was greatest for NPKO, followed by NPKB and least for the NPK treatment. A total of 8 214 ASVs were obtained from all the soil samples, belonging to 26 phyla, 75 classes, 165 orders, 176 families, and 251 genera （excluding unidentified fungi）. Proteobacteria, Actinobacteria, and Chloroflexi were the dominant phyla, accounting for 54.85% of all ASVs. Compared to that in the NPK and NPKB treatments, the NPKO treatment had the highest bacterial diversity and number of significantly different taxa, and soil AN, AP, AK, SOC, TN, and IFI were significant correlates of bacterial diversity index （P<0.05）. Additionally, pH, TN, and SOC were significant influencers of bacterial taxa differences （P<0.05）, with importance ranked as TN （70.59%） &gt; SOC （49.42%） &gt; pH （27.08%）. Structural equations suggested that pH-related soil properties and bacterial community diversity were the direct pathways influencing IFI, and soil pH-related soil characteristics could also indirectly affect IFI by affecting bacterial Shannon diversity. These results indicate that soil fertility and bacterial community structure were significantly different and correlated between the biochar and organic fertilizer addition treatments and that pH and bacterial community diversity were the key factors influencing IFI, with the NPKO treatment in particular having the best effect on improving IFI. Considering the effect of soil fertilization and the functional group of bacteria, NPKO is the recommended combination for the best synergistic effect of soil fertilization, that is, N 150 kg·hm-2+P2O5 135 kg·hm-2+K2O 135 kg·hm-2+organic fertilizer 6.6 t·hm-2.

Implementation factors of tuberculosis control program in primary healthcare settings in China: a mixed-methods using the Consolidated Framework for Implementation Research framework

BackgroundTuberculosis (TB) is a major cause of death worldwide, and Chinese TB burden ranked the second globally. Chinese primary healthcare (PHC) sectors implement the TB Control Program (TCP) to improve active case finding, referral, treatment adherence, and health education. This study aimed to identify barriers and enablers of TCP implementation in high TB burden regions of West China.MethodsWe conducted a representative study using mixed-methods in 28 counties or districts in Chongqing Municipality and Guizhou Province of West China from October 2021 to May 2022. Questionnaire surveys and semi-structured in-depth interviews were conducted with 2720 TB healthcare workers (HCWs) and 20 interviewees in PHC sectors. Descriptive statistical analysis was used to investigate TB HCWs’ characteristics, and path analysis model was utilized to analyze the impact of associated factors on TCP implementation. Thematic framework analysis was developed with the guide of the adapted Consolidated Framework for Implementation Research (CFIR) on factors of TCP implementation.ResultsThis study found that 84.6% and 94.1% of community and village HCWs had low professional titles. Based on the results of multiple regression analysis and correlation analysis, lower TB core knowledge scores (-0.09) were identified as barriers for TCP implementation in community PHC sectors, and low working satisfaction (-0.17) and low working willingness (-0.10) are barriers for TPC implementation in village PHC sectors. The results of in-depth interviews reported barriers in all domains and enablers in four domains of CFIR. There were identified 19 CFIR constructs associated with TCP implementation, including 22 barriers such as HCWs’ heavy workload, and 12 enablers such as HCWs’ passion towards TCP planning.ConclusionsWith the guide of the CFIR framework, complex factors (barriers and enablers) of TCP implementation in PHC sectors of West China were explored, which provided important evidences to promote TB program in high TB burden regions. Further implementation studies to translate those factors into implementation strategies are urgent needed.Graphical

Assemble and comparative analysis of the mitochondrial genome of Rhododendron delavayi: Insights into phylogenetic relationships and genomic variations

Rhododendron delavayi, a notable ornamental plant primarily found in regions of China like Yunnan and Guizhou provinces, holds substantial horticultural value. To elucidate the systematic phylogenetic relationships and organelle genomic differences within R. delavayi and related Rhododendron species, we conducted sequencing and assembly of the complete mitochondrial genome of R. delavayi. The full-length mitochondrial genome of it was a singular circular molecule spanning 1,009,263 bp, comprising 53 protein-coding genes, including 18 transfer RNA (tRNA) genes, 3 ribosomal RNA (rRNA) genes, and 32 protein-coding genes. A total of 1,182 simple sequence repeats (SSRs) loci were identified in the R. delavayi mitochondrial genome, primarily consisting of single nucleotide, dinucleotide, and trinucleotide repeats. Nucleotide diversity analysis highlighted five genes (atp6, atp9, cox2, nad1, and rpl10) with the highest diversity within the mitochondrial genomes of Rhododendron genus. Comparative analysis of the mitochondrial genome of R. delavayi with those of four other Rhododendron species indicated complex rearrangements in 21 genes, including rps4, nad6, rps3, atp6, cob, atp9, nad7, among others. The mitochondrial phylogenetic tree revealed a close relationship between R. delavayi and R. decorum, forming a sister clade to R. × pulchrum and R. simsii. Furthermore, 126 plastid-to-mitochondrial gene transfers in R. delavayi were identified, ranging from 30 bp to 19,385 bp. These fragments collectively constituted 47.54 % and 9.52 % of the chloroplast and mitochondrial genomes (202,169 bp), respectively. Complex mitochondrial-to-mitochondrial transfers were also observed, with 843 identified fragments totaling 312,036 bp (30.92 % of the mitochondrial genome). Segments exceeding 10 kb may mediate homologous recombination within the mitochondrial molecules. Remarkably, our study underscores that the mitochondrial genome of R. delavayi was the largest reported within the Rhododendron genus to date. The intricate rearrangements observed in the mitochondrial genomes of Rhododendron species, alone with the identification of five potential molecular marker sites, provided valuable insights for species classification and parentage identification within the Rhododendron genus.

Diversity of causal agents of Pseudostellaria heterophylla leaf spot from Guizhou Province, China

AbstractPseudostellaria heterophylla, a valuable Chinese herbal medicine, is widely cultivated in China, with a planted area of 5402.7 hm2 in Shibing County, Guizhou Province. The occurrence of leaf spot disease represents a significant challenge in the production area. In this study, 30 samples of P. heterophylla exhibiting symptoms of leaf spot were collected from three primary production areas in Guizhou Province. Following isolation and purification, 51 isolates were classified into two genera based on both cultural and conidial characteristics, along with ITS sequence data. Fourteen representative strains were selected for morphological and multigene molecular identification, which revealed that these representative strains were affiliated with Alternaria arborescens species complex (SC), Alternaria tenuissima, Alternaria gaisen, and Sclerotiophoma versabilis. The isolation rates of Alternaria and Sclerotiophoma were 84.3% and 15.7%, respectively. Pathogenicity tests confirmed the identity of the causal agents and demonstrated varying levels of aggressiveness among the different genera and species of pathogens towards P. heterophylla leaves. This study marks the first identification of A. arborescens SC, A. gaisen, and S. versabilis as pathogens causing leaf spot in P. heterophylla in China.

First report of leaf blight caused by Nigrospora hainanensis on Euonymus japonicus in China.

Euonymus japonicus Thunb., belonging to the family Celastreace and native to East Asia, is a widely cultivated evergreen ornamental woody plant with important ecological and economic values. In May 2023, serious leaf blight of E. japonicus occurred in the campus green space at Guiyang University, Guizhou Province, China (26°55'85"N, 106°78'04"E). Early symptom appeared as small, circular light brown spots on the edges or tips of the leaves. Then, the spot developed visible necrosis, initially light brown to dark brown halos with clear margins. Subsequently, severely infected leaves appear totally wilt, and significantly decrease their ornamental values. In a 0.07-ha field, the disease incidence reached to 40-55%. To identify the pathogen, ten typical symptomatic E. japonicus leaves were collected. They were initially immersed in 75% ethanol for 3 min, and by sodium hypochlorite (4% NaClO) solution for 45 s, and ultimately rinsed with sterile distilled water (dH2O) five times for not less than 1 min each time, then, placed the leaves on potato dextrose agar (PDA) medium and cultured for 5 days at 25°C in constant temperature incubator. Cultures were purified to yield eight isolates. Early colonies are white and regularly rounded, gradually turning dark brown to black with fluffy mycelium. Conidia were single celled, smooth, black, spherical or ellipsoidal. The conidia size of the representative strain, GY-2 and GY-3, was averagely 12.3-17.3 µm × 10.8-17 µm (n = 50). The conidiogenous cells were monoblastic, hyaline, globose or ampulliform. Morphology-based identification revealed the strain as Nigrospora spp. (Wang et al., 2017). For further confirmation, PCR of GY-2 and GY-3 DNA was performed with the primers ITS1/ITS4 (White et al., 1990), Bt2a-F/Bt2b-R (Glass and Don-aldson 1995), and TEF1-728F/TEF1-986R (Carbone and Kohn 1999). Sequences of the ITS region, TUB and TEF1 genes from the strain GY-2 and GY-3 were deposited in GenBank. (GY-2: OR999377, PP112221 and PP150467; GY-3: PP406871, PP421045 and PP421046, respectively). BLAST analysis showed GY-2 100%, 100%, and 98.36%; GY-3 99.43%, 98.21% and 100% (ITS region, TEF1, and TUB) identity to N. hainanensis sequences (accession numbers. NR_153480.1, KY019415.1, and KY019464.1; KX986094.1, OP611475.1, and KY019597.1). Additionally, tandem sequences of ITS, TUB and TEF1 constructed by MEGA 7.0 confimed the homology through the phylogenetic tree. Pathogenicity tests were conducted on healthy plants grown, each 5 mm diameter of active growing mycelium plug of isolate GY-2 was attached to 15 leaves from five healthy 2-year-old E. japonicu plants. The same number of leaves in the control group were treated with non-inoculated plugs only. All the plants were incubated at 25°C and 75% relative humidity with a 16-h/8-h photoperiod. After 10 days, no symptoms appeared on the leaves of the control group. In contrast, symptomatic blight appeared on all leaves inoculated with GY-2. Pathogenicity tests were performed five times. Pure strains were re-isolated from diseased leaves and, confirmed to be N. hainanensis based on the above methods. Recently, Nigrospora oryzae was reported as causal agent of leaf spots on Euonymus japonicus in China (Xu et al., 2023). To our knowledge, this study is the first report of N. hainanensis causing leaf blight on E. japonicu. Identification of the etiological agent may provide assistance for sustainable management in the future.

Spatial differentiation characteristics of selenium in Se-rich yellow soils developed from black shale and coal bearing formations in Guizhou Province

Spatial differentiation characteristics of selenium in Se-rich yellow soils developed from black shale and coal bearing formations in Guizhou Province

Graph convolutional LSTM algorithm for real-time crash prediction on mountainous freeways

Accurate real-time traffic crash prediction is crucial for proactive traffic safety management. Currently, the majority of real-time models forecast crashes every 5 min to support different intelligent transportation systems. However, these intervals might be too short for practical use in manually implementing proactive traffic safety measures such as deploying traffic law enforcement and emergency rescue resources. Therefore, this study develops hourly crash prediction models to provide network operators with sufficient time to take measures in advance. A section of a mountainous freeway in Guizhou province is divided into homogeneous segments, with crash data, traffic operations data, and meteorological data being collected hourly. As the result is an imbalanced dataset of crash and non-crash instances, the training dataset is resampled using synthetic minority over-sampling technique (SMOTE) to address the issue. To fully capture the complex spatiotemporal relationships in the data and achieve high crash prediction accuracy, a graph convolutional network-long short-term memory (GCN-LSTM) model is constructed for the first time, combining a graph convolutional network (GCN) and long short-term memory (LSTM) neural network. For comparison purposes, LSTM, Extreme Gradient Boosting (XGBoost), and logistic regression (LR) models are developed. The results show that the GCN-LSTM model outperforms other models in hourly traffic crash prediction, and the optimal prediction performance is achieved with the crash-to-non-crash ratio of 1:4. The GCN-LSTM method is found to effectively capture the complex spatiotemporal relationships in prediction data and to handle imbalanced traffic crash data.

Main nutritional components of food herbs in mountainous areas of Guizhou Province

To investigate the nutritional content of edible medicinal materials in mountainous areas of Guizhou Province and compare the comprehensive nutritional value of different varieties. A total of 15 kinds of edible herbs were collected from Guizhou Province. According to the national standard, direct drying method, Kjeldahl nitrogen determination method, Soxhlet extraction method, high performance liquid chromatography, inductively coupled plasma mass spectrometry and other detection method were used to determine the content of general nutrients, fat soluble vitamins, minerals and ash. According to the weight ranking of nutritional indexes in principal component analysis and membership function analysis, the quality of 9 kinds of food and drug substances and 6 kinds of Chinese medicinal materials were evaluated and ranked. The eigenvalues of the first 4 principal components were greater than 1, and the cumulative contribution rate was 82.32%. Compared with membership function analysis, the top 5 in comprehensive evaluation were Eucommia, Epimedium and honeysuckle, all of which were food and drug substances. The contents of calcium(851.69 mg/100 g), phosphorus(270.22 mg/100 g) and potassium(1446.48 mg/100 g) were the highest. The contents of carotene(21 963.87 μg/100 g) and vitamin E(57.82 mg/100 g) were the highest in the fat-soluble vitamins of Herbimedium. The contents of various indexes of honeysuckle were relatively high. Food and pharmaceutical substances have both medicinal value and nutritional value, and the overall nutritional benefit is higher than that of Chinese medicinal materials.