Spring In China Research Articles

Construction and Comparation of Critical Nitrogen Concentration Dilution Curves for Spring and Autumn Potato in China

Nitrogen is one of the essential nutrients for the growth and development of potato plants. The precise application of nitrogen can improve the yield and quality of potatoes and enhance their resistance to diseases. The changes in the critical N dilution curves of the shoot, root, and whole plants of potato were analyzed according to different N levels. The difference in the critical nitrogen concentration dilution curve of potatoes in spring and autumn was discussed. It is of great significance for the precise management of nitrogen fertilizer in spring and autumn potatoes. In this experiment, four field experiments were conducted using two potato cultivars (Zheshu956 and Yongma1) with four varying N application levels (N0–N3). Two identical varieties were planted at the same location in the spring and autumn and there was no significant difference in the selection of the same varieties between the two seasons. The dry matter and nitrogen concentration of roots, stems, leaves, and tubers were measured after transplantation at different stages. The results showed that the critical nitrogen concentration models for the shoot, root, and whole plant of potatoes were constructed as follows: spring potato shoot, N = 4.8712 W−0.203, root, Nc = 1.8477 W−0.157, and whole plant, Nc = 4.1679 W−0.293; autumn potato shoot, Nc = 3.8653 W−0.204, root, Nc = 2.1529 W−0.158; and whole plant, Nc = 3.2569 W−0.304. The critical nitrogen curves for the aboveground part and the whole plant of spring potato were significantly higher than that of autumn potato. Under N2 (160 kg ha−1) treatment, both spring and autumn potatoes reach their maximum yield. The critical nitrogen concentration dilution curve based on the whole plant was determined to be more appropriate for potatoes. The critical nitrogen concentration curves of potatoes in spring and autumn were significantly different for the aboveground part and the whole plant, but there was no significant difference for the underground part. The separately constructed nitrogen nutrition indices can be used to diagnose the nitrogen requirements of spring and autumn potatoes.

First Report of Xanthomonas hortorum pv. vitians as the Causal Agent of Bacterial Leaf Spot on Lettuce in China.

Lettuce (Lactuca sativa) is a leafy vegetable that belongs to the family Asteraceae. This cool-season crop grows well during Spring and Fall in China (Qi et al., 2021). In October 2023, a leaf disease with dark brown to black lesions was observed on lettuce (var. iceberg) in Yongning Town, Yanqing District, Beijing, China (40°53'N, 116°16'E). The disease incidence ranged from 10 to 40% in the surveyed greenhouse and field. Translucent and water-soaked brown spots were observed on the margins of leaf, then coalesced into large necrotic lesions surrounded by a chlorotic halo. Infected sections were soaked with 75% ethyl alcohol for 7 second, rinsed with sterile water for 15 second twice, and cut into pieces in the sterile water. The sample extracts were streaked on Nutrient agar medium. After incubation for 48 hours, 12 colonies were obtained and all the colonies were Gram-negative and aerobic with yellow, round-shape, smooth and glistening appearance. Four isolates SCZX1-SCZX4 with typical characteristics were selected for further identification tests. Pathogenicity test of SCZX1-SCZX4 was performed on the three-week-old lettuce (var. butterhead) by spraying with the bacterial suspension (108 CFU·ml-1). Inoculated lettuce were incubated at 26℃ and 70% relative humidity in the growth chamber. Another set of lettuce plants were mock inoculated with sterile distilled water. Three trials were carried out per isolate, and each treatment included fifteen lettuce plants. Symptoms appeared within 7-10 days after inoculation and are identical to those naturally infected lettuces. Negative control plants had no symptoms. The 16S rRNA region and two housekeeping genes (gyrB and atpD) of each isolate were amplified with universal primers F27/R1492 (Monciardini et al., 2006) and specific primers (Roach et al., 2018), respectively. According to BLAST analysis of each isolate (Genbank accession number PP027925, PP140779, PP140781 to PP140783, PP137422 to PP137428), BLAST searches of the obtained sequences revealed 100.0% of 16S rRNA region(1400/1400 nucleotides), 100.0% of gyrB(774/774 nucleotides), and 100.0% of atpD(768/768 nucleotides) identity and query coverage to Xhv CFBP 498 (Genbank accession number LR828257.1). Phylogenetic analysis revealed that SCZX1-SCZX4 clustered with the neopathotype strain Xhv LMG 938PT, which was isolated from a diseased L. sativa in Zimbabwe (Timilsina, S et al., 2015). Physiological and biochemical tests of SCZX1-SCZX4 were conducted by the BIOLOG GENIII microplate system (Biolog, Hayward, CA, USA), and the test results are consistent with the Xhv LMG 938PT (Morinière, L et al., 2020) and L1-L7 (Pernezny, K et al., 1995). Strains were re-isolated from re-inoculated lettuce, then re-identified as Xhv by the same method, fulfilling Koch's postulates. Bacterial leaf spot (BLS) is a worldwide-spread lettuce disease caused by numerous bacterial pathogens, including Xhv (Dia, N.C et al., 2022), Pseudomonas cichorii (Patel, N et al., 2021) and P. viridiflava (Alippi, A. M et al., 1999) etc. Xhv had been widely reported as the causal pathogen of BLS in Turkey (Sahin, F et al., 2000), United States (Bull, C.T et al., 2007), Saudi Arabia (Al-Saleh, M et al., 2008), and France (Morinière et al., 2020). However, the first report of Xhv causing BLS on lettuce in China is significant to provide pathogen information for growers in making effective measures to manage this disease.

Spatiotemporal patterns in persistent precipitation extremes of the Chinese mainland (1961–2022) and association with the dynamic factors

Previous studies on extreme precipitation events have primarily focused on the intensity of such events during fixed periods, without considering the entirety of extreme precipitation events and conducting a comprehensive examination of the intensity and frequency of more disastrous persistent extreme precipitation (PEP) events. In this paper, persistent extreme precipitation indices (PEPIs) related to intensity, frequency, duration, and contribution rates were constructed, utilizing a gridded daily precipitation dataset and atmospheric circulation indices data from China for the period 1961–2022 to analyze the spatial distribution, spatiotemporal trends, and seasonal patterns and variations of PEPIs across different regions of China and the potential impact of the dynamic factors on the spatiotemporal variations of PEPIs. The results are crucial for effectively predicting future changes and informing planning for adaptation strategies: From 1961 to 2022, (1) China's PEP pattern displays distinct regional variations. PEP has been prevalent in Western Arid (Semi-Arid) Zone (WAS) and Qinghai-Tibet Plateau (QT) regions, with higher occurrence frequency, duration, and contribution rates to total extreme precipitation (44.91% and 42.01%) and overall precipitation (26.35% and 29.08%). Conversely, the humid eastern regions exhibit greater event intensity. (2) Intensity-related PEPIs show a significant increase, while the frequency and contribution rate-related PEPIs tend to decrease, indicating less frequent but more concentrated PEP events. (3) Seasonal distribution of PEP events shows a primary concentration in QT, North China (N), the Eastern arid zone (EA), and Northeast China (NE) from June to September and they occur more frequently during spring and summer in Central (C) and South China (S) regions. Summer variations predominantly account for annual PEP variability and trends. (4) WPSHII, SCSSHII, WPWPSII, APVII, NHPVII, NINO3 predominantly affect the WAS, QT, NE, C, and S regions, with WPSHII having the broadest impact, notably on the QT, C, S, and NE regions. In the WAS region during autumn, the interaction of NAO and WPSHII explains 72% of the intensity of PEP events.

Satellite-Based Reconstruction of Atmospheric CO2 Concentration over China Using a Hybrid CNN and Spatiotemporal Kriging Model

Although atmospheric CO2 concentrations collected by satellites play a crucial role in understanding global greenhouse gases, the sparse geographic distribution greatly affects their widespread application. In this paper, a hybrid CNN and spatiotemporal Kriging (CNN-STK) model is proposed to generate a monthly spatiotemporal continuous XCO2 dataset over China at 0.25° grid-scale from 2015 to 2020, utilizing OCO-2 XCO2 and geographic covariates. The validations against observation samples, CAMS XCO2 and TCCON measurements indicate the CNN-STK model is effective, robust, and reliable with high accuracy (validation set metrics: R2 = 0.936, RMSE = 1.3 ppm, MAE = 0.946 ppm; compared with TCCON: R2 = 0.954, RMSE = 0.898 ppm and MAE = 0.741 ppm). The accuracy of CNN-STK XCO2 exhibits spatial inhomogeneity, with higher accuracy in northern China during spring, autumn, and winter and lower accuracy in northeast China during summer. XCO2 in low-value-clustering areas is notably influenced by biological activities. Moreover, relatively high uncertainties are observed in the Qinghai-Tibet Plateau and Sichuan Basin. This study innovatively integrates deep learning with the geostatistical method, providing a stable and cost-effective approach for other countries and regions to obtain regional scales of atmospheric CO2 concentrations, thereby supporting policy formulation and actions to address climate change.

Pathogen identification and epidemic factor analysis of yellow catfish, Pelteobagrus fulvidraco, red lower jaw disease

Since 2020, another type of epidemic disease, ‘red lower jaw disease’ (RLJD), has broken out in yellow catfish Pelteobagrus fulvidraco every spring in China, causing large-scale deaths and significant economic losses. This new disease has the characteristics of strong infectivity, high mortality and a single host. To prevent and control RLJD, epidemiological investigation, transmission electron microscopy (TEM), virome sequencing, Koch's rule verification and epidemic factor investigation were studied in this article. The clinical symptoms of diseased yellow catfish were pale gill filaments, hyperaemia and swelling of the spleen and kidney. TEM results revealed that a large number of 35–40 nm spherical virus particles without envelope structure were found in the cytoplasm of spleen cells. The liver, spleen and kidney of the diseased fish had serious lesions. After virome sequencing, the calicivirus reads in the unique virus reads accounted for 99.5% of the unique virus reads in the diseased fish, which provided a relevant reference value for identifying the pathogen of RLJD. The full-length sequence of yellow catfish calicivirus (YCCV) obtained at 7405 bp, including the RNA-helicase domain, RdRp-1 domain and d1iqqa domain. At the same time, both PCR and TaqMan fluorescence quantitative PCR detection method of YCCV were established. Through the artificial infection test, YCCV was verified as the pathogen for RLJD. It was also found that YCCV mainly harmed the fish within 1 year, whereas the fish above 2 years had good resistance. The water temperature of the RLJD outbreak was mainly concentrated at 18 °C–24 °C. In the current study, after YCCV was verified as the pathogen of RLJD, epidemic factors including fish age and water temperature were studied, to the best of our knowledge, for the first time to provide a relevant theoretical basis for the pathogenic mechanism and prevention and control measures of yellow catfish RLJD.

The Role of Color Psychology in Interaction Design

Interaction design is a multidisciplinary profession in which psychology plays an important role. The purpose of design is to solve the problem, and a better solution can provide a better user experience, so the key to our user experience lies in the user's psychology. As early as the end of the Spring and Autumn period in China, the first theoretical document on design "Kaogong Ji" recorded the "five elements and five colors" (color), and the importance and role of humanistic care for design. Color affects our perceptual system, and color psychology is a subjective feedback to the objective world. On the basis of introducing the concept of color psychology and interaction design, the principles and methods of interaction design are proposed by using color psychology.

Effects of rainfall on the karst-related carbon cycle due to carbonate rock weathering induced by H2SO4 and/or HNO3

To determine the mechanism underlying the effect of rainfall on the karst-related carbon cycle while controlled by that of H2SO4 and/or HNO3, high-resolution monitoring was conducted in Lanhuagou Spring, which is a typical epikarst spring in southwest China. During the monitoring period, the signals from major elements and stable isotopes showed that the CO2 generated by H2SO4 and/or HNO3 entirely escaped from the water. Therefore, the CO2 consumption induced by H2CO3 and CO2 emission induced by H2SO4 and/or HNO3 jointly affected the karst-related carbon cycle. The CO2 consumption induced by H2CO3 dropped following rainfall events and recovered gradually thereafter, which was only affected by the retention time of infiltrating water (dilution effect of rainfall). However, the CO2 emission induced by H2SO4 and/or HNO3 had showed a downward trend from the first rainfall event (R1) to the end of monitoring. The effects of rainfall on CO2 emission induced by H2SO4 and/or HNO3 were related to both the dilution effect and the removal of H2SO4 and/or HNO3. Although the average CO2 consumption induced by H2CO3 dropped from 2.8 mmol/L before rainfall to 2.21 mmol/L thereafter (decreased by 21.07 %), the average CO2 emission induced by H2SO4 and/or HNO3 dropped from 1.29 to 0.49 mmol/L (decreased by 62.02 %); the range of CO2 emission induced by H2SO4 and/or HNO3 decline (0.8 mmol/L) was larger than that of CO2 consumption induced by H2CO3 (0.59 mmol/L), resulting in higher net CO2 consumption (CO2 consumption induced by H2CO3 minus CO2 emission induced by H2SO4 and/or HNO3) after rainfall than before rainfall in the monitoring period. Therefore, in the model used to predict karst-related carbon flux caused by global climate change, it is necessary to consider the impact of rainfall on CO2 emission induced by H2SO4 and/or HNO3. Importantly, the net CO2 consumption rather than CO2 consumption induced by H2CO3, as well as runoff should be considered as two multipliers when carbonate weathering is interfered by H2SO4 and/or HNO3.

Gansulinema gen. nov. and Komarkovaeasiopsis gen. nov.: Novel Oculatellacean genera (Cyanobacteria) isolated from desert soils and hot spring.

To increase the understanding of simple thin filamentous cyanobacteria in harsh environmental areas, we previously isolated and identified four strains (XN101, XN102, GS121, NX122) from desert soils and hot spring in China. As a result, two new Oculatellacean genera of these four strains, Gansulinema gen. nov. and Komarkovaeasiopsis gen. nov., are described based on a polyphasic approach. The ultrastructure of these strains showed a similar arrangement of peripheral thylakoids with three to four parallel layers, indicating that they belonged to the orders Nodosilineales, Oculatellales, or Leptolyngbyales. In the 16S rRNA gene phylogeny, two sequences of the Gansulinema strains and the two sequences of the Komarkovaeasiopsis strains formed two independent and robust clusters, within the order Oculatellales. The 16S rRNA gene sequences of strains of Komarkovaeasiopsis and Gansulinema showed low identity to each other (≤93.2%) and to other sequences of the Oculatellacean genera (≤94.5% and ≤93.3%, respectively). Furthermore, the 16S-23S internal transcribed spacer rRNA region secondary structures of strains of Komarkovaeasiopsis and Gansulinema were not consistent with all existing descriptions of Oculatellacean taxa. These data suggest that cyanobacterial communities are rich sources of new taxa in under-exploited areas, such as desert soils and hot spring in China.

Transforming "Internet Celebrity " Elements into Yingjing Black Sand Product Design: An exploration of traditional handcrafts development

The history of the YingJing black sand product can trace back to the Spring and Autumn Periods in China. Like many traditional handicrafts, the techniques of this product list as a national intangible cultural heritage. In today's 5G world, consumers have increasingly high demands for fashion, unique cultural attributes, and product interest. YingJing black sand products have also faced unprecedented challenges. This paper aims to transform Internet celebrity elements into the Yingjing black sand product design to discuss the development of traditional handicraft products and the design methods and design models of cultural products derived from traditional handicrafts.

Delay-aware karst spring discharge prediction

As an essential component of the hydrological cycle at both regional and global scales, karst aquifers store large amounts of water, serving as the main source of fresh water supply in many areas. Karst springs provide a natural drainage pathway for karst groundwater systems to participate in the hydrological cycle. Accurate prediction of karst spring discharge is of great value to the long-term planning and management of karst water resources. The mainstream methods proposed have achieved high prediction accuracy by introducing deep learning technology. However, these methods ignore the delay time of spring water discharge to water supply or drainage, so there is still room for improvement in prediction accuracy. To address this issue, this paper proposes a delay-aware spring discharge prediction (DSDP) framework that introduces the delay time to predict spring discharge. Specifically, the framework consists of three modules, including a time calibration module, a variation estimation module and a discharge prediction module. The time calibration module identifies the delay time of spring discharge to each element to calibrate the observations. And the variation estimation module utilizes a neural network to infer spring discharge variations. Finally, the discharge prediction module predicts spring discharge with derived discharge variations. This study validates the performance of the proposed method by using spring discharge data from Jinci Spring, a typical karst spring in China. The experimental results show that the proposed method outperforms baselines, with significant decreases in both MAE and RSM. The study will provide evidence for the precise management of Jinci Spring, and provide a methodological reference for the discharge prediction of other springs.

Bacterial diversity in water from Xifeng Hot Spring in China.

The Xifeng Hot Spring is one of the eight largest hot springs in China, which is rich in radon gas and sulphur in karst scenery. Little is known about the microbiota structure in the spring. The water was collected from three sites containing the outlet of spring water discharge site (OWD), spring pool for tourist (SPT) and sewage effluent pool (SEP) in the Xifeng Hot Spring and further analyzed by culture-independent technique and culture-dependent method. A total of 57 phyla were identified from the water samples. The dominate phyla at OWD was Bacteroidetes (46.93%), while it was Proteobacteria in both sites of SEP and SPT with relative richness of 61.9% and 94.9%, respectively. Two bacteria, Deinococcus and Hymenobacter, that confirmed to be radiation-resistant, seven sulphur bacteria and three thermophilic bacteria were detected fromXifeng Hot Spring. Furthermore, it was found that genus Flavobacterium was susceptible to environmental change with abundance of 11 ~ 2825 times higher in OWD than the other two groups. Compared bacteria from the OWD group with that from 14 hot springs in six countries, total 94 unique genera bacteria were found out from the Xifeng Hot Spring including four thiometabolism-related bacteria (Propionispira, Desulforegula, Desulfobacter and Desulfococcus) and the thermophilic bacterium (Symbiobacterium). Using microbial culturing and isolation technology, sixteen strains were isolated from the water samples of three sites. The diversity of microbiota was abundant and variable along with the niche changed in conditions and surroundings. It indicated that numbers of valuable bacteria resources could be explored from the special surroundings of Xifeng Hot Spring.

Season-dependent heatwave mechanisms: A study of southern China

Heatwaves are among the deadliest weather-related disasters. They are not only seen in summer but also may appear in spring and autumn, especially under climate warming. Although the mechanisms of summertime heatwaves have been extensively studied, how they differ from spring and autumn seasons and possibly season-dependent mechanisms of heatwaves are poorly understood. Here we examine the specific processes associated with spring, summer, and autumn heatwaves in southern China during 1961–2020. We show that heatwaves in all three seasons are intensifying in frequency, duration, and intensity, and they exhibit distinctly season-dependent circulation changes. Summer heatwaves are characterized by a warm-core high-pressure structure, while spring and autumn heatwaves exhibit a warm low pattern. Summer heatwaves are mainly triggered by the westward (eastward) extension of the western North Pacific subtropical high (South Asian high), and are accompanied by anomalous lower-level anticyclone and positive pressure anomalies. In contrast, spring and autumn heatwaves coincide with lower-than-normal pressure and anomalous southwesterly over East Asia, indicative of a weakening of the East Asian winter monsoon circulation and the Siberian high. Their developments are linked to the eastward movement of an upper-tropospheric wave-like pattern over the mid-latitudes. It is also found that autumn heatwaves are largely contributed by local preceding soil moisture deficit, in comparison to spring and summer heatwaves. Our findings contribute to a better understanding of the heatwave characteristics in different seasons and provide insights into their mitigation strategies.

Identification of candidate genes that regulate the trade-off between seedling cold tolerance and fruit quality in melon (Cucumis melo L.).

Trade-offs between survival and growth are widely observed in plants. Melon is an annual, trailing herb that produces economically valuable fruits that are traditionally cultivated in early spring in China. Melon seedlings are sensitive to low temperatures, and thus usually suffer from cold stress during the early growth period. However, little is known about the mechanism behind the trade-offs between seedling cold tolerance and fruit quality in melon. In this study, a total of 31 primary metabolites were detected from the mature fruits of eight melon lines that differ with respect to seedling cold tolerance; these included 12 amino acids, 10 organic acids, and 9 soluble sugars. Our results showed that concentrations of most of the primary metabolites in the cold-resistant melons were generally lower than in the cold-sensitive melons; the greatest difference in metabolite levels was observed between the cold-resistant line H581 and the moderately cold-resistant line HH09. The metabolite and transcriptome data for these two lines were then subjected to weighted correlation network analysis, resulting in the identification of five key candidate genes underlying the balancing between seedling cold tolerance and fruit quality. Among these genes, CmEAF7 might play multiple roles in regulating chloroplast development, photosynthesis, and the ABA pathway. Furthermore, multi-method functional analysis showed that CmEAF7 can certainly improve both seedling cold tolerance and fruit quality in melon. Our study identified an agriculturally important gene, CmEAF7, and provides a new insight into breeding methods to develop melon cultivars with seedling cold tolerance and high fruit quality.

Prevalence and distribution of antibiotic resistance in the water environment of sea bass (Lateolabrax maculatus) breeding area in spring in South China

Antibiotic resistance represents a global health crisis for humans, animals, and the environment. However, few studies address the abundance and distribution of the environmental bacterial antibiotic resistance associated with farmed fish during the early breeding stages and their relationship with aquaculture environment. In this study, culture-dependent methods and gene chip technology were respectively used to identify and detect cultivable heterotrophic antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) of water samples from 20 sea bass-rearing ponds in spring in Zhuhai, China. Meanwhile, the relationships among ARGs, ARB, and water nutrients were elucidated. The results showed that bacterial resistance to erythromycin and sulfamethoxazole with trimethoprim was generally high (mean 48.15% and 18.07%, respectively), whereas resistance to rifampicin, florfenicol, ciprofloxacin, and enrofloxacin was generally low (mean 5.46%, 2.16%, 1.43%, and 0.16%, respectively). Acinetobacter sp. (42.31%) and Pseudomonas sp. (25.74%) were the dominant ARB, and most cultivable ARB were opportunistic pathogens. The abundance of sul family genes was higher than that of other tested ARGs. ARGs and ARB were mainly affected by NO3– and PO43–, with PO43– generally positively correlated, whereas NO3– was negatively correlated, with ARGs and ARB. Thus, recommendations for the control of antibiotic resistance risk can be made by understanding the resistance profile of the aquaculture environment.

Aerosol Physical–Optical Properties under Different Stages of Continuous Wet Weather over the Guangdong–Hong Kong–Macao Greater Bay Area, China

The spatiotemporal distributions and physical–optical properties of aerosols are of great scientific significance for the study of climate change and atmospheric environment. What are the characteristics of aerosols in constant high humidity? Continuous wet weather (CWW) is a special weather phenomenon that occurs frequently during the late winter and early spring in South China. In this study, the CALIPSO satellite data and the ERA5 and MERRA-2 reanalysis data are used to analyze the aerosol optical properties of a total of 68 CWW processes from 2012 to 2021 in the Guangdong–Hong Kong–Macau Greater Bay Area (GBA). We attempt to explore the variations in meteorological conditions and physical–optical properties of aerosols during the before-stage, wet-stage, and after-stage under different humidity levels. The results show that the prevailing wind direction is northeasterly and that the temperature and humidity are lower under the influence of cold high pressure in the before-stage. Moreover, the high aerosol optical depth (AOD) mainly results from regional transport. During the wet-stage, clean ocean airflow causes AOD to remain at a low level, whereas temperature and humidity increase significantly. The wet-stage ends with coldness when it is controlled by cold high pressure again. The atmospheric circulation in the after-stage is similar to that in the before-stage. However, a remarkable feature is that there is a temperature and humidity inversion layer, which results in a significant increase in AOD. This study reveals the physical–optical properties of aerosols during the three stages and the influence mechanism of meteorological factors on aerosols, which can provide a scientific basis for the study of CWW in the future.

Virulence Phenotyping and Molecular Genotyping Reveal High Diversity Within and Strong Gene Flow Between the Puccinia striiformis f. sp. tritici Populations Collected from Barberry and Wheat in Shaanxi Province of China.

Emergence of new Puccinia striiformis f. sp. tritici races that overcome resistance of wheat cultivars is a challenging issue for wheat production. Although sexual reproduction of the fungus on barberry plants under field conditions in the spring in China has been reported, the diversity of the pathogen on barberry plants and the relationship to the population in wheat fields have not been determined. In the present study, two P. striiformis f. sp. tritici populations collected in western Shaanxi Province in May 2016, one from barberry plants (103 isolates) and the other from nearby wheat crops (107 isolates), were phenotyped for virulence and genotyped with simple sequence repeat (SSR) markers. The phenotypic and genotypic data of the two populations were compared to determine their relationships. A total of 120 races, including 29 previously known races (seven were shared by the two populations) and 91 new races (35 from barberry and 56 from wheat), were identified. Similarly, a total of 132 multilocus genotypes, including 51 only from barberry, 77 only from wheat, and four from both, were detected using the SSR markers. Analyses of molecular variance identified high (93%) genetic variance within populations and low but still significant variance (7%) between the populations. Nonparametric multivariate discriminant analysis of principal components and STRUCTURE analysis showed that the two populations had a close relationship with little genetic differentiation (FST = 0.038) and strong gene flow (Nm = 6.34, P = 0.001) between them. Although the analysis of linkage disequilibrium indicated clonal populations, the isolation of P. striiformis f. sp. tritici from barberry plants and the high genetic diversities in the barberry and wheat populations suggest that barberry plants provide aeciospores to infect wheat crops in the area. The information is useful for understanding stripe rust epidemiology and management of the disease.

Flow–Solid Coupling Analysis of Ice–Concrete Collision Nonlinear Problems in the Yellow River Basin

Yellow River ice is the most prominent and significant natural disaster in winter and spring in China. During the drift ice period, water transmission tunnels located in this area tend to be hit by water–drift ice coupling. Thus, it is an important issue to reduce water transmission tunnel damage by drift ice, ensure the safety of operation and maintenance, and prevent engineering failure. In this paper, a numerical simulation of the collision process between ice and the tunnel is carried out by using the fluid structure coupling method and ANSYS/LS-DYNA finite element software. In addition, a model test with a geometric scale of 1:10 is carried out to verify the numerical simulation results, and the mechanical properties and damage mechanism of drift ice impacting the tunnel concrete lining in water medium are studied. The results show the following: the experimental values of maximum equivalent stress and X-directional displacement of the flow ice on the water transfer tunnel have the same trend as the simulated values, both of which show an increasing trend with an increase in flow ice velocity. It is shown that the ice material model parameters, ALE algorithm, and grid size used in this paper are able to simulate the impact of drift ice on the water transfer tunnel more accurately. With an increase in drift ice collision angle and drift ice size, the fitted curves of equivalent stress and peak displacement in X-direction all show relationships of exponential function. The peak value of displacement in the X-direction and maximum equivalent stress decrease with an increase in the curvature of the tunnel structure. It is also shown that the influence of change in drift ice size on the tunnel lining is greater than that of a change in tunnel section form. It is found that a high-pressure field will be formed due to extrusion of flowing ice, which should be fully considered in the numerical simulation. The research method and results can provide technical reference and theoretical support for prevention and control of ice jam disasters in the Yellow River Basin.

Quaternary rainfall variability is governed by insolation in northern China and ice-sheet forcing in the South

Quaternary Asian low-latitude hydroclimate cyclicity has long been attributed to insolation forcing, in contrast to the dominant ice-sheet and CO2 controls identified in mid-high-latitude regions. However, debates exist regarding these rainfall variations and forcings due to inconsistent reconstructions and simulations. Here, by combining rainfall proxy records with multi-model simulations, dominant 23 ka rainfall cycle in northern China and 100 ka rainfall cycle in southern China and Southeast Asia were found. We propose that rainfall mainly occurs in summer in the north, primarily driven by insolation. Rainfall in the south is largely forced by high-latitude ice sheets, with enhanced spring and autumn rainfall in southern China and weakened rainfall in western Maritime Continent during glacial periods. This study highlights the seasonal contributions to orbital-scale rainfall changes, and sheds light on the Asian hydroclimate conditions associated with high-low-latitude climate interactions.

A theoretical model for simulating periodic processes of intermittent karst springs considering changed recharge rates into siphon cavity

Intermittent karst springs (IKS) are common phenomena in karst areas where spring flow rates rise and fall in variable periods, which is generally attributed to the siphon structure in karst aquifers. However, the previous model assumed that the siphon cavity received a fixed recharge rate, thus the IKS showed a fixed periodic characteristic. In this study, an improved theoretical model (IKS model) was proposed to simulate the hydrological process of IKS with changing periods by considering the varying recharge rate from aquifers to the siphon cavity. The model uses two tandem tanks to represent the karst aquifer and siphon cavity separately. The numerical solution was obtained by the iterative method to predict the periodic variations of flow rate and eruption time of IKS. The IKS model was verified by physical experiments under four representative recharge conditions, showing good consistency between theoretical and experimental results. It reveals the hydrologic processes mechanism of the IKS by quantitatively describing the relationship between the cycle period of the IKS discharge variations and the flow exchanges in the siphon cavity-aquifer system. Furthermore, this model performs well in simulating the hydrological process of Chaoshuidong Spring in central China and approximately estimated the hydraulic coefficient of the aquifer in the basin based on observed periodic changes in spring discharge. These findings might be essential for the development, management, and protection of groundwater resources in IKS.

Dust pollution in China affected by different spatial and temporal types of El Niño

Abstract. Dust is an important aerosol affecting air quality in China in the winter and spring seasons. Dust in China is potentially influenced by the interannual climate variability associated with El Niño. Here, the impacts of El Niño with different temporal and spatial types on dust pollution in boreal winter and spring in China and the potential mechanisms are investigated using a state-of-the-art Earth system model (E3SMv1). We find that the eastern Pacific (EP) and central Pacific (CP) El Niño both increase wintertime dust concentrations by 5–50 µg m−3 over central-eastern China. Due to a stronger wind and lower relative humidity, which favor dust emissions near sources, and a strengthened northwesterly and reduced precipitation, which are conducive to dust transport, dust concentrations during the CP El Niño are 5–20 µg m−3 higher in northern China than during the EP El Niño, although the changes are mostly insignificant. El Niño with a short duration (SD) increases boreal winter dust concentrations by 20–100 µg m−3 over northern China relative to the climatological mean, while there is a decrease of 5–50 µg m−3 during the long-duration (LD) El Niño, which is also related to the El Niño-induced changes in atmospheric circulation, precipitation, and relative humidity. In the following spring season, all types of El Niño events enhance dust over northern China, but only the increase during the LD El Niño is statistically significant, suggesting that the weaker intensity but longer duration of the LD El Niño events can significantly affect spring dust in China. Our results contribute to the current knowledge of the influence of El Niño on dust pollution, which has profound implications for air pollution control and dust storm prediction.