Xinjiang Research Articles

Variation in Root-Associated Microbial Communities among Three Different Plant Species in Natural Desert Ecosystem.

The process and function that underlie the assembly of root-associated microbiomes may be strongly linked to the survival strategy of plants. However, the assembly and functional changes of root-associated microbial communities in different desert plants in natural desert ecosystems are still unclear. Thus, we studied the microbial communities and diversity of root endosphere (RE), rhizosphere soil (RS), and bulk soil (BS) among three representative desert plants (Alhagi sparsifolia, Tamarix ramosissima, and Calligonum caput-medusae) in three Xinjiang desert regions {Taklimakan (CL), Gurbantünggüt (MSW), and Kumtag (TLF)} in China. This study found that the soil properties {electrical conductivity (EC), soil organic carbon (SOC), total nitrogen (TN) and phosphorus (TP), available nitrogen (AN) and phosphorus (AP)} of C. caput-medusae were significantly lower than those of A. sparsifolia and T. ramosissima, while the root nutrients (TN and TP) of A. sparsifolia were significantly higher compared to C. caput-medusae and T. ramosissima. The beta diversity of bacteria and fungi (RE) among the three desert plants was significantly different. The common OTU numbers of bacteria and fungi in three compartments (RE, RS, and BS) of the three desert plants were ranked as RS > BS > RE. The bacterial and fungal (RE) Shannon and Simpson indexes of C. caput-medusae were significantly lower as compared to those of A. sparsifolia and T. ramosissima. Additionally, bacterial and fungal (RE and RS) node numbers and average degree of C. caput-medusae were lower than those found in A. sparsifolia and T. ramosissima. Root and soil nutrients collectively contributed to the composition of root-associated bacterial (RE, 12.4%; RS, 10.6%; BS, 16.6%) and fungal communities (RE, 34.3%; RS, 1.5%; BS, 17.7%). These findings demonstrate variations in the bacterial and fungal populations across different plant species with distinct compartments (RE, RS, and BS) in arid environments. More importantly, the study highlights how much soil and plant nutrients contribute to root-associated microbial communities.

The ancient mitochondrial genome of a Siberian roe deer (Capreolus pygargus) from Jartai Pass Site in Xinjiang, China, and its phylogenetic relationships

The ancient mitochondrial genome of a Siberian roe deer (Capreolus pygargus) coded as NJ26S from Jartai Pass Site was obtained by high throughput sequencing. The damage pattern demonstrated the authenticity and reliability of the ancient DNA data. The length of the mitogenome was 16,357 bp, which contained 13 protein-coding genes, two rRNA genes, 22 tRNA genes, and one control region. The total base composition of the mitochondrial genome is 28.17% A, 25.01% T, 11.89% G, 19.72% C, and 15.21% missing data with an AT composition of 53.18%. A maximum-likelihood phylogenetic tree was recovered including other roe deer sequences under the TIM2 + I + G4 model. This study presents molecular evidence indicating the presence of Capreolus pygargus in the Xinjiang Uygur Autonomous Region in China more than 3,000 years ago.

Bioremediation of uranium enriched coal fly ash based on microbially induced calcite precipitation

Coal fly ash (CFA) is an essential raw material in brickmaking industry worldwide. There are some coal mines with a relatively high content of uranium (U) in the Xinjiang region of China that are yet understudied. The CFA from these coal mines poses substantial environmental risks due to the concentrated uranium amount after coal burning. In this paper, we demonstrated a calcifying ureolytic bacterium Halomonas sp. SBC20 for its biocementation of U in CFA based on microbially induced calcite precipitation (MICP). Rectangle-shaped CFA bricks were made from CFA using bacterial cells, and an electric testing machine tested their compressive strength. U distribution pattern and immobility against rainfall runoff were carefully examined by a five-stage U sequential extraction method and a leaching column test. The microstructural changes in CFA bricks were characterized by FTIR and SEM-EDS methods. The results showed that the compressive strength of CFA bricks after being cultivated by bacterial cells increased considerably compared to control specimens. U mobility was significantly decreased in the exchangeable fraction, while the U content was markedly increased in the carbonate-bound fraction after biocementation. Much less U was released in the leaching column test after the treatment with bacterial cells. The FTIR and SEM-EDX methods confirmed the formation of carbonate precipitates and the incorporation of U into the calcite surfaces, obstructing the release of U into the surrounding environments. The technology provides an effective and economical treatment of U-contaminated CFA, which comes from coal mines with high uranium content in the Xinjiang region, even globally.

Drying and wetting trend in Xinjiang and related circulations background over the past 60 years

The study of climate variability and trend provides important evidence for water resource management strategies in Xinjiang. The scientific community has systematically studied the ‘warming and wetting’ process in the Xinjiang region. However, significant controversy persists regarding whether this trend has stagnated, and there remains a gap in understanding the decadal climate variability across different seasons within the subregions of Xinjiang. Here, we analyzed the spatiotemporal characteristics of seasonal-to-annual climate variations in Southern and Northern Xinjiang over the past 60 years by the Standardized Precipitation Evapotranspiration Index (SPEI-3) and identified the change points of mean and trend changes in the SPEI series and further explored the atmospheric circulation patterns before and after the transition from dry/wet conditions. Specifically, although the mean change point test indicated a wetter climate after 1986 at both the annual and seasonal scales, the trend analysis showed a shift from wet to dry from 1996, which has persisted until the present. There were significant interdecadal features in the spatial distribution of SPEI. Xinjiang exhibited a predominantly dry pattern from 1961 to 1980, which changed to a wetter pattern from 1981 to 2000, Xinjiang experienced its wettest decade from 1991 to 2000, and the whole region returned to a drier pattern from 2001 to 2020. From the annual and seasonal variation, the rate of change is greater in the south, with stronger change amplitude in summer and autumn and a higher frequency of anomalous SPEI. The results of the atmospheric circulation analysis demonstrated that the net water vapor flux in the Xinjiang region increased by about 8.30 g·kg−1·m·s−1 in the period 1987–2020 compared to 1961–1986 due to the combined interaction of high-, mid-, and low-latitude systems with the Central Asian low-pressure system. The results indicated a sharp increase in aridification in Xinjiang, providing valuable insights for disaster prevention, mitigation, and risk management related to regional drought hazards.

Abstract P106: Association of long term blood pressure variability and Major Cardiovascular events in patients with primary aldosteronism

Objective: Long-term blood pressure variability (BPV) is associated with an increased risk of major cardiovascular events (MACE), but it is rarely reported in patients with primary aldosteronism (PA). We aim to investigate the association between long-term BPV and cardiovascular events in patients with PA. Methods: This was a retrospective cohort study which conducted at the Hypertension Center of People’s Hospital of Xinjiang Uygur Autonomous Region from January 2006 to December 2021. The study included patients with PA aged over 30 years. The primary outcome was the incidence of major cardiovascular events during the follow-up, which extended until June 2023. The BPV index encompassed four parameters: standard deviation (SD), coefficient of variation (CV), average real variability (ARV), and maximum and minimum blood pressure difference (MMD). Multivariate analysis using logistic regression was performed, adjusting for demographic variables such as age, sex, body mass index, as well as clinical characteristics including smoking and alcohol consumption. Results: A total of 2,380 patients with PA were ultimately enrolled in this study. Access to clinic blood pressure was ensured at least three times during follow-up visits, with a minimum follow-up interval of 1 month. During a median follow-up of3.6 years, there were 124 cases of MACE. The mean age of the participants was 49.36 years, with men accounting for 1,288 cases. The average blood pressure recorded was 135 mmHg. After adjusting for confounding factors such as age, sex, smoking, alcohol consumption, BMI and cardiovascular risk factors, the systolic BPV (SD, CV, ARV) was found to be significantly associated with MACE (OR= 1.03, CI 1.02-1.05; P<0.05). In the group of mean SBP≥130mmHg, SBP variability had a significant association with MACE (OR: 1.03; CI: 1.01-1.06; P<0.05). However, no significant correlation between SBP variability and MACE in group of mean SBP <130mmHg (P>0 .05). Conclusion: Focusing on long-term systolic BP SD, CV, and ARV in patients with primary aldosteronism may help to prevent the occurrence of cardiovascular events.

The Migration, Diversity, and Evolution of Puccinia triticina in China.

Wheat leaf rust, caused by Puccinia triticina, is one of the most common fungal diseases of wheat in China and occurs widely in various wheat-growing regions. To clarify the epidemic, spread rules, and population structure of P. triticina among different regions, 217 isolates of P. triticina collected from Hebei, Shandong, Sichuan, and Xinjiang in China were tested by 34 Thatcher near-isogenic lines and 21 pairs of EST-SSR primers. A total of 83 races were identified, and THTT, PHTT, THTS, and PHJT were the most predominant races in the four provinces in 2009. We found enriched virulence and genetic diversity in the four P. triticina populations and a significant correlation between genetic polymorphism and geographic regions. However, no significant correlation was found between virulence phenotypes and molecular genotypes. Moreover, a notable high level of gene flow (Nm = 2.82 > 1) among four P. triticina populations was detected. The genetic relationship among Hebei, Shandong, and Sichuan populations was close, possibly due to the spread of P. triticina from Sichuan to Shandong and then to Hebei. In contrast, the Xinjiang population was relatively independent. Genetic differentiation analysis showed some level of differentiation among or within populations of P. triticina in the four provinces, and the genetic variation within populations (74.97%) was higher than across populations (25.03%). Our study provides a basis for a better understanding of the regional migration, epidemic, and population structure of P. triticina in China.

The Ecological Risks in Arid Zones from a Production–Living–Ecological Space Perspective: A Case Study of the Tuha Region in Xinjiang, China

The ecological and environmental problems of arid zones have become an urgent global concern. Current research on ecological risk is based mainly on the dominant functions of land use, with a primary focus on land use landscape projections and less consideration of potential risks to ecosystems, system resilience and interactions between nature and future sustainable development. In this study, a potential–connectivity–resilience ecological risk assessment model based on the SDGs was constructed using multisource data to spatially quantify indicators at the grid scale in the Turpan and Hami regions of Xinjiang, China. This model was used as a basis for studying ecological risk in arid zones from a production–living–ecological space (PLES) perspective. The results revealed that, during the period 2000–2020, PLESs in the Turpan and Hami regions presented significant spatial similarity, with an increasing trend in overall risk. The production space in the Turpan and Hami regions showed a parabolic trend of increasing and then decreasing, whereas the living space and ecological space in the Hami region showed continuous linear upward trends. The state of ecological security in the Turpan and Hami regions is gradually deteriorating, and comprehensive ecological protection and restoration measures are urgently needed to rationally allocate the structure and layout of the production-–living-–ecological space. The study of ecological risk from a PLES perspective not only helps in fully understanding the development trend of the arid zone; it also provides new ideas and methods for evaluating regional ecological environmental safety and scientific references for formulating regional sustainable development, ecological risk prevention and control and the rational allocation of resources.

Modeling of cotton yield responses to different irrigation strategies in Southern Xinjiang Region,China

Southern Xinjiang region represents a prototypical oasis agricultural area, and cotton is the primary cash crop. The current cotton water productivity for this area remains room for improvement. In order to refine cotton drip irrigation strategy in Southern Xinjiang, this study combined field experiment with crop model simulation and prediction. In this experiment, two irrigation methods, furrow irrigation and drip irrigation, and different degrees of deficit irrigation were set up. The impacts of soil moisture on cotton yield and quality were assessed, with the additional utilization of the Root Zone Water Quality Model (RZWQM2) for simulating irrigation scenarios and predicting cotton yield field data showed that during the 2021–2022 growing season, drip irrigation significantly increased boll weight, yield, and Water Productivity compared to furrow irrigation. The deficit irrigation with 90 % of full irrigation during the flowering period resulted in the highest yield among all drip irrigation treatments, while simultaneously improving the fiber quality. The RZWQM2 model was calibrated and validated using 2021 and 2022 cotton field experimental data, respectively. The calibrated and verified RZWQM2 model shows good performance. In terms of soil water storage, cotton yield and evapotranspiration. The simulated value output by the model is close to the measured value in the field. Model prediction data suggest that there is still room for improvement in cotton yield, accompanied by an increase in evapotranspiration. But deficit irrigation below 80 % of the full irrigation quotas poses a notable risk of yield reduction. Targeting higher yields, the predicted scenario suggests an increase in water application (irrigation quota:314.8 mm). Additionally, this study proposes irrigation regimes with water savings of 10 % and 20 %, with irrigation quotas of 290.5 mm and 266.5 mm during the growth period, respectively. Based on this study, we provide a more detailed and reliable water-saving scheme for cotton drip irrigation in southern Xinjiang region.

Genetic diversity and population structure of Plenodomus biglobosus on flixweed (Descurainia sophia) in northwestern China.

Plenodomus biglobosus (Pb), a causal agent of blackleg of rapeseed, is composed of several subspecies, including 'australensis' (Pba), 'brassicae' (Pbb) and 'canadensis' (Pbc). Besides rapeseed, Pb can infect many wild cruciferous plants (WCPs), such as flixweed (Descurainiasophia) and pennycress (Thlaspi arvense), which may become the infection source for blackleg of rapeseed. However, Pb on WCPs has not been well investigated in China. This study identified the blackleg fungi on two WCPs in Sayram Lake and Zhaosu County in Xinjiang of China: flixweed (15 isolates) and pennycress (1 isolate) as well as on rapeseed (971 isolates). They belonged to Pba (11), Pbb (18) and Pbc (958). Pba occurred on flixweed (10) and pennycress (1) only in Sayram Lake, whereas Pbb and Pbc occurred on flixweed (1 and 4 isolates, respectively) and rapeseed (17 and 954 isolates, respectively) in Zhaosu County. Then, virulence of 16 isolates from flixweed and pennycress was determined on rapeseed. Their genomes were sequenced and used to identify the mating-type idiomorphs and to analyze population genetic structure. Results showed that all of the 16 isolates were virulent to rapeseed. Only MAT1-1 was detected in 11 Pba isolates, implying that Pba may lack sexual reproduction. The 16 isolates from two WCPs were divided into four genetic groups: Group I for Pbc (4 isolates), Group II for Pbb (1 isolate), and Group III (3 isolates) and IV (8 isolates) for Pba. The findings about the single mating-type in Pba and its limited geographic distribution provided a case showing the importance of sexual reproduction in epidemics of Pb. To the best of our knowledge, this is the first report of Pba, Pbb and Pbc on flixweed, and Pba on pennycress in China.

Field study on vibration characteristics of geocell-reinforced aeolian sand subgrades

Constructing highways in deserts is expensive due to the difficulty of acquiring materials; utilizing aeolian sand effectively has become a problem, especially in the Xinjiang region, where the desert widely occurs. This paper aims to investigate the vibration response of a geocell-reinforced aeolian sand subgrade under traffic loading based on field tests of highways in deserts. The vibration acceleration response of geocell-reinforced aeolian sand and gravelly soil upper roadbed structures is tested. The field test results illustrate the effects of dynamic loading on geocell-reinforced aeolian sand roadbeds, and the thickness substitution ratio between geocell-reinforced aeolian sand roadbeds and conventional gravelly soil roadbeds is determined and verified based on the vibration acceleration monitoring values. The results show that the vibration response induced by the test vehicle is concentrated within the 30 Hz frequency band, and the higher the vibration frequency, the faster the vertical decay in the road. The vibration damping capacity of the reinforced aeolian sand roadbed is better than that of the gravelly soil roadbed; when replacing the gravelly soil roadbed with the reinforced aeolian sand roadbed, the substitution ratio is 0.31–0.42. It is verified that half thickness of gravel soil on roadbeds can be replaced by geocell-reinforced aeolian sand under different working conditions. The results of this study can provide reference data for the design of highway subgrades in deserts.

Understanding the failure of government debunking communication: insights from China

ABSTRACT This study uses qualitative methods to examine the challenges faced by authoritarian regimes in managing rumors during public crises, focusing on the Urumqi government’s (the capital of the Xinjiang Uyghur Autonomous Region in Northwestern China) response to COVID-19 lockdown rumors. The analysis identifies four factors contributing to the failure of government debunking communication: Rejection due to Negative Past Experiences, Discourse Reinterpretation by Mismatched Criteria, Disregard Toward Inflexible Statements, and Opposition Arising from Perceived Superficial Efforts. These factors culminate in a core mechanism termed ‘Emotional Resistance Anchored in Distrust,’ highlighting how negative past experiences shape public distrust and foster resistance to government communication. The findings challenge the assumption of automatic public trust in authoritarian contexts and underscore the importance of aligning government actions with public needs and expectations, particularly during crises.

Leaf phenology and paleoclimatic and paleoenvironmental insights derived from Yiwupitys elegans of the Yiwu Jurassic Forest, Xinjiang, China

Many permineralized conifer stems and trunks have been documented from the Jurassic strata of the Xinjiang Uygur Autonomous Region (Xinjiang), Northwest China. Xylem anatomical studies have showed that these stems and trunks belonged to a diverse range of plants. However, the leaf phenology and the paleoclimatic and paleoenvironmental significance of these fossil plants have rarely been studied. We quantitatively analyzed the anatomical characteristics of a permineralized conifer stem—Yiwupitys elegans Gou et Feng 2023—from the Middle Jurassic Xishanyao Formation in northeastern Xinjiang, which has distinct and wide growth rings in the secondary xylem. Analyses of the Mean Sensitivity and Ring Markedness Index of the growth rings suggest that a stable paleoclimate with regular seasonal fructifications likely prevailed during the Middle Jurassic in this area. The statistical analyses of cell diameters and anatomical features of leaf traces in six successive growth rings indicate that this fossil plant was deciduous. Our study elucidates the ecophysiological characteristics of a Middle Jurassic conifer plant and provides new insights into the corresponding paleoclimate and paleoenvironment based on quantitative cellular analysis of the fossil stem.

Comprehensive Evaluation of Texture Quality of ‘Huizao’ (Ziziphus jujuba Mill. Huizao) and Its Response to Climate Factors in Four Main Production Areas of Southern Xinjiang

A superior cultivar of dried jujube in China is ‘Huizao’ (HZ) jujube. Nonetheless, detailed evaluations of the texture quality of HZ fruit have been the subject of few studies. Texture is a significant indicator of the sensory and processed quality of a fruit. Here, we differentiate and characterize the texture quality of HZ fruit from the four primary producing regions in southern Xinjiang, as well as develop a system for assessing the texture quality of HZ fruit. Correlation investigation indicated strong relationships between the springiness, chewiness, cohesiveness, gumminess, and hardness of HZ fruit. Furthermore, according to the factor molecules, the texture quality of HZ fruit in the four production areas was evaluated as Bazhou (1.24) > Hotan (0.773) > Kashi (−0.577) > Aksu (−0.852). RDA analysis of six texture quality parameters and 24 climate conditions identified higher mean temperature (TEM) and lower relative humidity (RHU) as the primary factors contributing to the improved texture quality of HZ fruit in Xinjiang. This study identified the variations in the texture of HZ fruit in the four primary producing regions of Southern Xinjiang. The HZ fruit in Hotan and Bazhou exhibit superior springiness and stickiness, while the fruit in Aksu and Kashi exhibit greater hardness. The texture of HZ fruit is significantly influenced by springiness, hardness, and adhesiveness, and a comprehensive evaluation model has been established through this research. This will provide a theoretical foundation for optimizing the dominant producing areas and regional production of HZ varieties in Xinjiang.

Evaluation of spatial conflicts of land use and its driving factors in arid and semiarid regions: A case study of Xinjiang, China

The study of spatial conflicts of land use (SCLU) is an important breakthrough to reveal the evolution mechanism of regional human-land relationship. Accurate identification of SCLU and scientific exploration of its spatio-temporal characteristics of their driving factors are pivotal for regional sustainable development. However, the basic theoretical system of SCLU still needs to be improved, and the spatio-temporal characteristics of SCLU at different spatial scales and landforms as well as the spatio-temporal correlation effects of its driving factors need to be further studied. This study utilizes theoretical models for the identification of SCLU. Employing a comprehensive index approach involving ArcGIS, FRAGSTATS landscape pattern analysis, and the multi-scale geographically weighted regression model, the spatio-temporal characteristics of SCLU are analyzed across different administrative scales and Macro-landforms. The investigation unveils the intrinsic mechanisms of spatio-temporal differentiation driven by various factors from 2000 to 2020 in the arid and semiarid region of Xinjiang, China. Results indicated that: (1) SCLU is a sensitive indicator of human-land interaction, measurable using conflict risk and effect; (2) The SCLU in Xinjiang presents a spatial pattern of “severe conflict around the three mountains and mild conflict around the two basins” and the SCLU transitioned from an outbreak to a relief stage over the past two decades; (3) SCLU varies significantly among landform types, with conflict intensity in Plain > Mountains > Platform > Hill areas; (4) Elevation and slope in natural environmental factors, human footprint and distance of patches from water, from roads, and from railroads in social activity factors have inhibitory effects on SCLU, and GDP, population density, and human impact index in economic development factors have positive effects on SCLU, and focusing on controlling potentially high-conflict risk areas and enhancing the upgrading of ecological quality are key to mitigating SCLU. The results validate the proposed theoretical framework and provide theoretical and practical references for accurately identifying SCLU and optimizing national territory spatial patterns.

Evaluating the coordinated development between digital technology and local safety management capability: evidence from 31 provinces in China

The enhancement of local safety management capabilities through digital technology represents a pivotal strategy for implementing Peaceful China Initiative. However, limited research exists on whether these capabilities can establish a coordinated development relationship with digital technologies and the factors influencing this relationship. This paper employs the concept of coordinated development to establish an analytical framework termed ‘Feasibility-Suitability-Sustainability,’ which is utilized to identify indicators for measuring the relationship between the two variables. Using panel data from China mainland, this study evaluates the relationship. The findings indicate that the overall level of coordinated development between digital technologies and local safety management capabilities in China mainland has been increasing during the period from 2018 to 2022. Nonetheless, certain provinces, particularly in the western regions, such as Tibet Autonomous Region, Qinghai province, and Xinjiang Uyghur Autonomous Region, encounter significant challenges in achieving high coordination between digital technologies and local safety management capabilities. Key factors contributing to these challenges include a lack of innovative potential in local safety management and insufficient trust in digital technologies among citizens. The research results contribute a novel explanatory framework to coordinated development theory and offer practical guidance for local government digitalization and public safety enhancement.

Molecular Detection of Theileria ovis, Anaplasma ovis, and Rickettsia spp. in Rhipicephalus turanicus and Hyalomma anatolicum Collected from Sheep in Southern Xinjiang, China.

The Xinjiang Uygur Autonomous Region (Xinjiang) borders eight countries and has a complex geographic environment. There are almost 45.696 million herded sheep in Xinjiang, which occupies 13.80% of China's sheep farming industry. However, there is a scarcity of reports investigating the role of sheep or ticks in Xinjiang in transmitting tick-borne diseases (TBDs). A total of 894 ticks (298 tick pools) were collected from sheep in southern Xinjiang. Out of the 298 tick pools investigated in this study, Rhipicephalus turanicus (Rh. turanicus) and Hyalomma anatolicum (H. anatolicum) were identified through morphological and molecular sequencing. In the southern part of Xinjiang, 142 (47.65%), 86 (28.86%), and 60 (20.13%) tick pools were positive for Rickettsia spp., Theileria spp., and Anaplasma spp., respectively. Interestingly, the infection rate of Rickettsia spp. (73%, 35.10%, and 28.56-41.64%) was higher in Rh. turanicus pools than in H. anatolicum pools (4%, 4.44%, and 0.10-8.79%) in this study. Fifty-one tick pools were found to harbor two pathogens, while nineteen tick pools were detected to have the three pathogens. Our findings indicate the presence of Rickettsia spp., Theileria spp., and Anaplasma spp. potentially transmitted by H. anatolicum and Rh. turanicus in sheep in southern Xinjiang, China.

Temporal and spatial distribution of PM2.5 in the Xinjiang region based on AOD fusion data and the GTWR model

ABSTRACT By integrating MODIS aerosol optical depth data and combining it with ground-based PM2.5 measurements and meteorological data, a geographically and temporally weighted regression (GTWR) model was used to estimate the spatiotemporal distribution of PM2.5 in Xinjiang in 2022. Findings include the following: (1) The GTWR model effectively represents PM2.5 distributions, with a correlation coefficient of 0.92, surpassing the geographically weighted regression model by 5.7% and the land use regression model by 9.5%. (2) Monthly PM2.5 levels in Xinjiang exhibit a pattern of initial decline followed by an increase. Elevated coal-fired heating in February and high air humidity in July contribute to higher atmospheric particulate concentrations. The peak monthly average concentration reaches 79.05 µg m−3 in February, and the lowest concentration drops to 33.86 µg m−3 in July. (3) Influenced by dust-prone conditions and atmospheric diffusion in the Taklimakan Desert region, PM2.5 levels in Xinjiang show a notable southwest-to-northeast gradient.

A Study of Precipitation Inversion in Xinjiang Region Based on FY-4A and Machine Learning Models

To compensate for the fact meteorological observation stations in Xinjiang are sparse, and spatial and temporal resolution of precipitation monitoring is insufficient in existing studies, in this study the authors proposed a precipitation inversion model that is based on infrared observation data from the Fengyun-4A satellite and the machine learning method. By combining multichannel satellite remote sensing data with ground meteorological observations, they constructed various machine learning models, such as deep forest, random forest, LightGBMs (light gradient-boosting machines), and XGBoost (extreme gradient boosting), using root-mean-square error, mean absolute error, and the coefficient of determination to evaluate and compare the model performance. The trained deep forest model was used to invert the precipitation in Xinjiang from June to August2023. The results show that the machine learning method is effective in exploiting the nonlinear relationship between the satellite observation features and the ground precipitation, and the inversion results are in good agreement with the ground observation data. Among these models, the deep forest model performs best in daytime conditions, and LightGBM is slightly better in nighttime conditions.

Powdery Mildew of Xanthium strumarium Caused by Podosphaera xanthii in central China.

Xanthium strumarium, known as cocklebur, is an annual herb and has been used in traditional Chinese medicine. In October 2020, powdery mildew-like disease signs and symptoms were observed on X. strumarium grown in a crop field, Xinxiang city, Henan Province, China (35.36076° N, 113.93467° E). The specimen (PX-XS2023) was stored in Xinxiang Key Laboratory of Plant Stress Biology. White colonies in irregular or coalesced circular shaped-lesions were abundant on both ad- and abaxial surfaces of leaves and covered up to 99 % of the leaf area. Some of the infected leaves were senesced. More than 70 % of plants (n = 130) exhibited these signs and symptoms. Conidiophores were straight or slightly curved, 55 to 160 × 11 to 13 μm composed of foot-cells, shorter cells and conidia. Conidia were ellipsoid to oval, 29 to 40 × 14 to 20 μm (n = 50), with a length/width ration of 2.0 to 2.5, containing fibrosin bodies. Dark brown to black chasmothecia were found on infected leaves. The appendages were mycelium-shaped and at the base of scattered or gregarious chasmothecia (n = 50, 70 to 120 μm in diameter). Asci were 55 to 80 × 50 to 65 μm (n=30). These morphological characteristics were consistent with those of Podosphaera xanthii (Braun and Cook 2012). The internal transcribed spacer (ITS) region and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) region of the fungus (PX-XS2023) were amplified and sequenced with primers ITS1/ITS4 (White et al. 1990) and GAPDH1/GAPDH3R (Bradshaw et al. 2022) according to a previously reported method (Zhu et al. 2022). The resulting sequences were respectively deposited into GenBank (Accession No. MW300956 and PP236083). BLASTn analysis indicated that the sequences were respectively 99.82 % (564/565) and 100% (272/272) identical to P. xanthii (MT260063 and ON075658). The phylogenetic analysis indicated that the strain PX-XS2023 and P. xanthii were clustered into a same branch. Therefore, the causal agent of powdery mildew on X. strumarium was P. xanthii. To conduct pathogenicity assays, mature leaves of five healthy X. strumarium (height in 50 centimeters) were inoculated with fungal conidia by gently pressing surfaces of infested leaves onto leaves of healthy plants (Zhu et al. 2020). Five untreated plants served as controls. The controls and inoculated plants were separately maintained in greenhouses (humidity, 60%; light/dark, 16 h/8 h; temperature, 18°C). Eight days post-inoculation, signs of powdery mildew were detectable on inoculated plants, however, the controls were asymptomatic. Thus, the fungal pathogen was morphologically and molecularly identified and confirmed as P. xanthii. This powdery mildew caused by P. xanthii was previously reported on X. strumarium in Korea, Russia and India (Farr and Rossman, 2021). In addition, P. xanthii was recorded on X. strumarium in Xinjiang Province, China (Tai 1979). However, this is the first report of P. xanthii on X. strumarium in central China, where is around 3000 km away from Xinjiang Province with geographically differences. The sudden presence of powdery mildew caused by P. xanthii may adversely affect plant health and thus reduce medical value of X. strumarium. Therefore, the identification and confirmation of P. xanthii infecting X. strumarium enhance the knowledge on the hosts of this pathogen in China and will provide fundamental information for disease control in the future.

Research on Improving the Accuracy of SIF Data in Estimating Gross Primary Productivity in Arid Regions

Coupling solar-induced chlorophyll fluorescence (SIF) with gross primary productivity (GPP) for ecological function integration research presents numerous uncertainties, especially in ecologically fragile and climate-sensitive arid regions. Therefore, evaluating the suitability of SIF data for estimating GPP and the feasibility of improving its accuracy in the northern region of Xinjiang is of profound significance for revealing the spatial distribution patterns of GPP and the strong coupling relationship between GPP and SIF in arid regions, achieving the goal of “carbon neutrality” in arid regions. This study is based on multisource SIF satellite data and GPP observation data from sites in three typical ecosystems (cultivated and farmlands, pasture grasslands, and desert vegetation). Two precision improvement methods (canopy and linear) are used to couple multiple indicators to determine the suitability of multisource SIF data for GPP estimation and the operability of accuracy improvement methods in arid regions reveal the spatial characteristics of SIF (GPP). The results indicate the following. (1) The interannual variation of GPP shows an inverted “U” shape, with peaks values in June and July. The cultivated and farmland areas have the highest peak value among the sites (0.35 gC/m2/month). (2) The overall suitability ranking of multisource SIF satellite products for GPP estimation in arid regions is RTSIF > CSIF > SIF_OCO2_005 > GOSIF. RTSIF shows better suitability in the pasture grassland and cultivated and farmland areas (R2 values of 0.85 and 0.84, respectively). (3) The canopy method is suitable for areas with a high leaf area proportion (R2 improvement range: 0.05–0.06), while the linear method is applicable across different surface types (R2 improvement range: 0.01–0.13). However, the improvement effect of the linear method is relatively weaker in areas with high vegetation cover. (4) Combining land use data, the overall improvement of SIF (GPP) is approximately 0.11%, and the peak values of its are mainly distributed in the northern and southern slopes of the Tianshan Mountains, while the low values are primarily found in the Gurbantunggut Desert. The annual mean value of SIF (GPP) is about 0.13 mW/m2/nm/sr. This paper elucidates the applicability of SIF for GPP estimation and the feasibility of improving its accuracy, laying the theoretical foundation for the spatiotemporal coupling study of GPP and SIF in an arid region, and providing practical evidence for achieving carbon neutrality goals.