Table of Content

20 July 2025, Volume 34 Issue 7

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A study of the distribution of the parasitic herb Cynomorium songaricum based on the optimized MaxEnt model： Current status assessment and future predictions

Yu-xia AN, Wen-qiang WANG, Dian YU, Yong-liang LIANG, Jun-long YANG, Xiao-wei LI

2025, 34(7):  1-12.  DOI: 10.11686/cyxb2024319

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Cynomorium songaricum is a nationally protected plant in China， and appears on a list of species accorded “second-class” protection. C. songaricum is esteemed for its high medicinal value， and thrives in ecologically fragile desert regions. In recent years， climate change has posed a significant threat to the geographical distribution of C. songaricum. This study aimed to clarify the main environmental factors affecting the distribution of C. songaricum in China and to emphasize the significance of identifying potential suitable areas for effective protection and management. Based on 166 valid distribution records and 39 natural environmental variables， this study employed the maximum entropy model （MaxEnt） to simulate the potential geographical distribution of C. songaricum along two representative climate change projection pathways （SSP126 and SSP585） for both the current period and future scenarios （2050s and 2070s）. The study explored the most critical environmental factors affecting C. songaricum distribution and predicted the spatial distribution pattern of suitable habitat areas in response to climate change. The knife-cut method was employed to assess the contribution rate of environmental variables to the model， helping to identify the primary factors influencing the distribution of C. songaricum. The model’s prediction results indicated that the currently simulated potential distribution area of C. songaricum closely aligns with its actual distribution. The area under the receiver operating characteristic curve （AUC value） was 0.900， indicating strong predictive performance. The results indicate that precipitation in the wettest month and average temperature during the coldest season are critical variables determining the habitat of C. songaricum. These two criteria are followed in importance by basic soil saturation， altitude， the highest temperature in the warmest month and precipitation in the driest season， in that order. Future climate change is expected to narrow the habitat of C. songaricum and shift its distribution eastward. The predictions of potential suitable habitat areas for C. songaricum in this study can provide guidelines for its protection and management.

Grassland health assessment of alpine grassland in the Yellow River Source Park of Three-Rivers Headwaters National Park

Bing-shu ZHU, Jiang-wen FAN, Hai-yan ZHANG, Lin HUANG, Hai-jing TIAN, Lin WANG, Shou-xing WANG, Ming-xin YANG, Yan-ming GUO

2025, 34(7):  13-27.  DOI: 10.11686/cyxb2024306

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Grassland health is a key indicator of the integrity， stability， and sustainability of grassland ecosystems. In recent years， conservation efforts in the Yellow River Source Park of Three-Rivers Headwaters National Park have restored degraded grasslands. However， a systematic assessment of the current grassland health status is still lacking. This study draws on ecosystem health theory to clarify the concept of grassland health. Based on the characteristics of alpine grasslands， and application of expert experience， a comprehensive grassland health index （GHI） was developed to reflect the overall grassland health status. The GHI includes indicators such as vegetation community， land surface characteristics， biodiversity， and forage performance. The health status and grades of alpine grasslands in the Yellow River Source Park in 2022 were assessed by zone， type， and class. The results show that： 1） Alpine steppe and alpine meadow differ in their vegetation community characteristic index （VCI）， land surface characteristic index （LCI）， biodiversity index （BDI）， and forage production performance index （FPI）， with the most significant difference observed in the BDI. 2） The overall GHI （64.98） of the Yellow River Source Park indicates a sub-healthy status， with the alpine steppe GHI （66.70） slightly higher than the alpine meadow GHI （62.30）. The Poaannua alpine steppe has significant differences from other alpine steppe types， and there are also significant differences in GHI among the types of alpine meadow. 3） From the functional zoning perspective， the GHI of the core protected area （59.30） is lower than that of the general controlled area （69.50）， likely due to fragile ecological conditions， historical long-term overgrazing， and the fact that newly designated core protected areas have yet to fully recover. This study provides a new methodological perspective for the ecological protection and future improvement of the conservation status of the Three-Rivers Headwaters National Park and provides a scientific criterion for improving the spatial layout of the natural reserve system.

Responses of soil pH to different fertilization practices in natural grasslands of northern China

Shao-yu YUAN, Shi-hui HAN, Tian XIA, Ning-bo HE, Jian-jie ZHANG

2025, 34(7):  28-40.  DOI: 10.11686/cyxb2024342

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Soil pH is a critical factor influencing plant growth and soil nutrient availability in grassland ecosystems. Fertilization is as an essential practice for rehabilitating degraded grasslands and may significantly affect soil pH. This study aimed to examine the impacts of various fertilization strategies on soil pH in natural grasslands in northern China， with an aim to provide scientific evidence and methodological references for optimizing restoration practices for degraded grasslands. A total of 63 articles published between 2000 and 2024， encompassing 461 datasets， were used for these analyses. A meta-analysis was employed to quantitatively assess the effects of chemical nitrogen fertilizer， combined nitrogen and phosphorus application， and organic fertilizer on soil pH. Additionally， the primary factors influencing soil pH under different fertilization regimes were identified using the random forest method. The results indicated that overall， the application of chemical nitrogen fertilizer resulted in the most substantial decrease in soil pH with a reduction of 5.31%， and its effect was further intensified with increased rates and duration of fertilization. Nitrogen and phosphorus application resulted in a 2.92% decrease in soil pH， whereas organic fertilizer application exhibited no significant overall effect on soil pH. The response of soil pH to fertilization varied significantly across different grassland types， climate conditions， and initial soil pH levels. The random forest analysis revealed that the fertilization rate， duration of fertilization， initial soil pH， and annual rainfall were pivotal factors affecting the soil pH response to fertilization. Among these， fertilization rate was the principal factor influencing soil pH under chemical nitrogen fertilization （increase in mean square error=52.40%）. Initial soil pH was the principal factor affecting the soil pH response to combined nitrogen and phosphorus application and organic fertilizer application （mean square error increases of 22.80% and 22.20%， respectively）. Correlation analyses revealed that the soil pH response to chemical nitrogen fertilization was positively correlated with the initial soil pH and negatively correlated with the duration and rate of fertilization. The response of soil pH to combined nitrogen and phosphorus application was positively correlated with the initial soil pH， and negatively correlated with annual rainfall and duration of fertilization. The response of soil pH to organic fertilization was positively correlated with annual average temperature， annual rainfall， and the fertilization rate， but negatively correlated with altitude. Organic fertilizer application had no significant overall effect on soil pH， but it significantly increased the pH of acidic and neutral soils and decreased the pH of alkaline soil. Therefore， grassland restoration strategies should consider using organic fertilizer， or a combination of organic and inorganic fertilizer， and other measures tailored to the particular soil pH conditions to ensure the stability of grassland ecosystems.

Spatial variation and factors influencing the soil organic carbon pool in grape-producing areas at the eastern foothills of Helan Mountain in Ningxia

Yu-xia WANG, Ling-tong DU, Zhi-yuan YI, Xiao LUO, Li SU, Cheng-long QIAO, Bin XUE

2025, 34(7):  41-53.  DOI: 10.11686/cyxb2024312

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The cultivation of vineyards in arid desert grassland is not only of economic benefit， but also has a potential role in increasing the carbon sink capacity of the ecosystem. In this study， the grape-producing area on the eastern foothills of Helan Mountain in Ningxia was used as a study site. Soil samples were collected from soil layers at successive 20 cm depth increments in a 0-100 cm soil profile between May and July 2023， and the soil organic carbon （SOC） content and the total carbon content were measured. In addition， the active， neutral， and inert SOC content were also measured in the upper soil layer （0-40 cm）， which is intensely disturbed by cultivation. The characteristics of SOC pools were studied for different soil types in typical vineyards using a geospatial interpolation technique and one-way ANOVA and factors influencing their variability are discussed. It was found that： 1） SOC content in the 0-100 cm soil depth ranged from 3.0 to 11.1 g·kg^-1 in the grape-producing area， indicating a lack of soil fertility， with an average SOC density of 52.85 t·ha^-1 and moderate variability. The SOC enrichment coefficient in the upper soil layer （0-40 cm） was greater than 1， indicating a stronger carbon sequestration capacity in the upper soil layer. 2） The total carbon， SOC， active SOC， and inert SOC contents in the upper soil layer （0-40 cm） were higher in the west than in the east of the grape-producing area， which was impacted by organic carbon inputs from grape cultivation and thus has significant spatial heterogeneity. 3） The soil carbon pool in the grape-producing area was stable since inorganic carbon constituted 74.8% of the total carbon and inert SOC accounted for 50% of SOC， resulting in low activity of the soil carbon pool. 4） Due to the different soil development scenarios， characteristics of SOC varied significantly with soil type. Although sandy soil had a SOC density higher than a sierozem soil， its SOC content was lower； sandy soil had the highest SOC density and carbon pool activity resulting in lower SOC stability. These findings provide scientific data for the carbon sink accounting and inventory of vineyard ecosystems at the eastern foothills of the Helan Mountains in Ningxia.

Soil pH distribution characteristics and environmental factors influencing it in sandy desert grassland in the Junggar Basin

Yi-sheng JING, Zong-jiu SUN, Hui-xia LIU, Didaer·Bisulidan, Mei-sha LI, Chen-ye ZHOU, Lei ZHOU, Bing-jie YU, You-zheng LI, Li ZHENG, Asitaiken·Julihaiti

2025, 34(7):  54-68.  DOI: 10.11686/cyxb2024335

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The aim of this study was to explore the distribution characteristics of soil pH and the factors affecting it in sandy desert grassland in the Junggar Basin. First， 136 sample plots were selected and established by a route survey combined with a typical sample plot layout， and the pH of soil samples collected from 0 to 100 cm depth in each plot was measured. Environmental factors such as temperature， vegetation cover， and species richness were determined， and meteorological data were collected. The factors affecting the spatial variation of soil pH were explored on the basis of the environmental and meteorological data and “3S” technology， using one-way ANOVA， geostatistical analysis， and geographical detectors drawing on a range of remote sensing data and analytical tools. The results showed the range of soil pH in each soil layer from 0 to 100 cm was 8.54-8.76， and the average value was 8.66. The soil pH showed an upward trend as the soil depth increased. The soil pH of the small arbor group （8.71） was 1.02 times that of the shrub group （8.54） and 1.01 times that of the subshrub group （8.59） （P<0.05）. Analyses of soil pH distribution showed that alkaline soil （pH 7.5-8.5） was mainly distributed in the northern part of Jimunai County， the southern part of Fuhai County， and the northern part of Karamay City around the Junggar Basi， and strongly alkaline soil （pH>8.5） was mainly distributed in Fukang City， Hutubi County， Manas County， Fuyun County， and other areas. Semi-variance variation analysis showed that the nugget effect of the optimal model of soil pH in the 0-100 cm soil layer was 49.91%， indicating that its spatial variation was affected by both structural factors and random factors. Geographic detector analysis showed that the main environmental factors contributing to the spatial variation of soil pH were mean average temperature （0.159）， vegetation coverage （0.152）， snow water equivalent （0.085）， root soil moisture （0.076）， and species richness index （0.066）. The results of this study add new information about the distribution of soil pH to the database for sandy desert grassland in Junggar Basin， and reveal the main factors contributing to variations in soil pH. These findings provide a theoretical basis for sandy desert management and ecological restoration.

The impact of ammonium nitrogen fertilizer application rates on nitrogen leaching and surface electrochemical properties of various purple soils

Xin-yu CHEN, Zheng-xin DENG, Zi-fang WANG, Jun XIE, Wen-cai DAI, Ming GAO

2025, 34(7):  69-82.  DOI: 10.11686/cyxb2024307

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Nitrogen fertilizer application plays an important role in world food production and in ensuring food security in China. To elucidate the effects of different ammonium nitrogen fertilizer application rates on nitrogen leaching and surface electrochemical properties of various types of purple soil， a pot experiment was conducted. Three different types of purple soil were selected， and four treatments were set up： no nitrogen fertilizer （CK）， low nitrogen （N₁， 0.1 g elemental nitrogen per kg soil）， medium nitrogen （N₂， 0.2 g elemental nitrogen per kg soil）， and high nitrogen （N₃， 0.4 g elemental nitrogen per kg soil）. The results showed that with increasing nitrogen fertilizer application rates， compared with the control group （CK）， the pH values of red brown purple soil， gray brown purple soil， and brown purple soil under the N₃ treatment decreased by 0.9， 1.2， and 0.8， respectively. Meanwhile， the cumulative leaching losses of ammonium nitrogen and nitrate nitrogen in these three types of soil increased significantly （P<0.05）. The ammonium nitrogen leaching losses under the N₃ treatment increased by 7.1， 15.4， and 12.5 times compared with those under the control （CK） treatment， respectively. There was almost no nitrate nitrogen leaching loss in the CK treatment. The nitrate nitrogen leaching losses under the N3 treatment increased by 6.1， 4.9， and 1.8 times compared with those under the N₁ treatment， respectively（P<0.05）. The surface potential （φ₀）， surface electric field strength （E₀）， and surface charge density （σ₀） of the three types of purple soil showed similar increasing trends， while the specific surface area （S） and surface charge number （SCN） decreased. Under the same nitrogen fertilizer application rates， there were differences in nitrogen leaching and surface electrochemical properties among the different types of purple soil. In the N₃ treatment， the cumulative leaching of ammonium nitrogen in gray-brown purple soil was significantly higher than that in the other two types of purple soil. Additionally， under all nitrogen fertilizer treatments， the cumulative total amount of nitrate nitrogen leached in gray-brown purple soil was significantly higher than that in red-brown purple soil （P<0.05）. Under the N₁ treatment， φ₀ of gray-brown purple soil was higher， while under the N₃ treatment， φ₀ of brown purple soil was significantly higher than that of the other two soil types. Under all treatments， the E₀ of gray-brown purple soil was significantly higher than that of the other two soil types （P<0.05）. Furthermore， under the N₂ and N₃ treatments， the σ₀ of gray-brown purple soil was also significantly higher than that of the other two soil types （P<0.05）. S under the N₁， N₂， and N₃ treatments ranked： red-brown purple soil>brown purple soil>gray-brown purple soil. Under the N₃ treatment， SCN of red-brown purple soil was significantly higher than that of the other two soil types （P<0.05）. Therefore， excessive application of ammonium nitrogen fertilizer can lead to soil acidification in purple soils， significantly altering their surface electrochemical properties and reducing their ability to adsorb and retain nutrients.

Comparative study of rhizosphere soil fungal community structure among different plants in Tomur Peak， Xinjiang

Ying WANG, Ming-yuan LI, Mairiyangu·Yasheng, Ji-lian WANG

2025, 34(7):  83-94.  DOI: 10.11686/cyxb2024417

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The aims of this study were to explore the structure and function of the rhizosphere fungal community in different plant species growing around Tomur Peak， and to determine how these characteristics contribute to the maintenance of ecosystem stability. High-throughput sequencing technology was used to detect differences in fungal community structure in the rhizosphere soil among four plants； Codonopsis javanica，Poa annua， Geranium wilfordii， and Medicago sativa. Correlations between soil physicochemical properties and fungal community structure were also analyzed. The results showed that Shannon’s index and Simpson’s index， indicators of rhizosphere soil fungal diversity， were higher in C. javanica than in the other plant species. A non-metric multidimensional scaling analysis showed that the fungal community structure of C. javanica differed from that of the other plant species. Across all samples， the dominant fungal phyla in the rhizosphere soil were Ascomycota， Mortierellomycota， Basidiomycota， and Chytridiomycota. Mortierellales and Hypocreales were the dominant fungal orders， but their relative abundance varied among the four plant species. Among all samples， the dominant nutritional pattern of fungi was saprotrophic （32.1%-52.5%）， followed by symbiotrophic in rhizosphere soil of C. javanica （9.3%）； pathotrophic-saprotrophic inrhizosphere soil of G. wilfordii （4.1%）， and pathotrophic in rhizosphere soils of P. annua and M. sativa （8.3% and 15.8%， respectively）. Undefined saprophytic fungi was the dominant functional group （28.6%-44.2%）， but the proportions of other functional groups differed among plant species. In conclusion， we detected significant differences in the structure and composition of rhizosphere soil fungal communities among plant species. These results provide a theoretical basis for understanding the environmental adaptation strategies of alpine plants and for designing ecological restoration strategies for this region.

Effects of fungal diseases of silage maize on microbial diversity of silage fermentation

Tian-ci KONG, Xue-qing MA, Chen-bang HE, Tai-yan FAN, Guang-xin LU, He-xing QI

2025, 34(7):  95-106.  DOI: 10.11686/cyxb2024317

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This research explored the effects of fungal diseases of silage maize on microbial diversity and community structure of maize silage during fermentation. Fermentation of maize silage without any disease （CK） was compared with that of silage maize infected by Alternaria leaf spot disease （YLG）， Bipolaris sorokiniana leaf spot disease （YM）， Ustilago maydis silage maize （YL） and common rust （YX）， with three replicates per treatment. After 40 days of silage fermentation， Illumina amplicon sequencing technology was used to analyze the fungal and bacterial diversity of microbial communities in each sample. The analysis revealed that the microbial structure of silage maize samples was composed of 6 phyla， 50 orders and 164 genera of fungi and 11 phyla， 43 orders and 123 genera of bacteria. The fungal taxa Ascomycota and Basidiomycota were the dominant phyla in each sample， with a total abundance of more than 90% in each sample. The abundance of the fungal genera Fusarium and Candida in silage maize with disease was higher than that in the CK treatment， and the abundance of Penicillium and Aspergillus in the YM and YX was higher than that in the CK treatment， while the abundance of Wickerhamomyces in silage maize with disease was lower than in the CK treatment. Firmicutes and Proteobacteria were the dominant bacterial phyla in each sample， with a total abundance of more than 99% in each case. The abundance of Enterococcus and Weissella was higher in the CK treatment than in the treatments with disease； and Streptococcus was only present in the CK treatment， with a relative abundance of 0.003%. In summary， this study has clarified the microbial community structure during maize silage fermentation in disease-free crop substrate and in crops affected by four different fungal diseases and identified the dominant bacterial genera present during fermentation in each case. Our study showed that the presence of fungal diseases resulted in an increase in the abundance of disease-causing pathogens， which decreased the abundance of Enterococcus， Weissella and Streptococcus. These changes would potentially have a negative impact on the silage fermentation environment， and affect the normal progress of the fermentation process， possibly leading to a decline in silage quality. Our results also provide information for the subsequent study of quality in maize silage.

Analysis of SSR characterization in full-length transcriptome and development of SSR molecular markers for Littledalea racemosa

Gui FU, Yu-ping LIU, Xu SU, Rong-ju QU, Zha-xi CAIRANG

2025, 34(7):  107-119.  DOI: 10.11686/cyxb2024304

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Littledalea racemosa is a herb with significant ecological and economic value belonging to the Poaceae family and endemic to Qinghai-Xizang Plateau. Identification of a suitable set of simple sequence repeat （SSR） molecular markers offers an important technical means for studying genetic diversity， phylogenetics， and species distribution patterns. In this study， 14089 SSR sequences were obtained using MISA software from 30624 Unigene sequences derived from the L. racemosa full-length transcriptome with the Pacbio sequencing platform. The value of incidence of SSR was 33.85%. Analysis of SSR characteristics， indicated six types of SSR locus nucleotide repeats， with mono-nucleotide， di-nucleotide， and tri-nucleotide being the dominant repeat motifs and accounting for 97.35% of all nucleotide types. Among these three dominant motif types， tri-nucleotide SSRs were the most frequently encountered， with a total of 10 detected. The CCG/CGG motif type was most common and occurred at a total of 1736 SSR sites， accounting for 31.32% of the total SSR tri-nucleotide sites. Twelve samples of L. racemosa were selected randomly from different populations and used by PCR amplification and agarose gel electrophoresis examination for 160 pairs of primers， and 15 pairs of SSR primers with stable amplification and specificity were finally obtained. For these 15 pairs of SSR primers， polymorphism of 81 individuals from 27 populations was analyzed， and a total of 132 alleles could be amplified， with an average of 8.8 alleles amplified per primer pair. The effective allele number （Ne）， Shannon information index （I）， polymorphic information content （PIC）， observed heterozygosity （Ho）， and expected heterozygosity （He）， were 4.7799， 1.6959， 0.7270， 0.8575， and 0.7648， respectively. Cluster analysis was conducted using the UPGMA method based on Nei’s genetics distance， and the results showed that there were explicit genetic relationships among the populations and individuals within a population of L. racemosa. The genetic distance between different populations may be related to geographical distance. The 15 pairs of SSR primers developed in this study have rich genetic diversity， which can provide effective marker selection for genetic variation research in germplasm resourcesof L. racemosa.

Effects of adding cellulase to the starter diet on the production performance， organ development， fatty acid composition， and serum antioxidant indices of Hu lambs

Chun-yan REN, Zhi-yun HAO, Rui BING, Ying-dong HUO, Hai-bi ZHAO, Peng-fei YIN, De-fu TANG, Shu-qin LIN, Ji-qing WANG

2025, 34(7):  120-131.  DOI: 10.11686/cyxb2024414

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We investigated the effects adding cellulase to the starter diet on the production performance， organ development， muscle fatty acid content， and serum antioxidant indexes of Hu lambs. Twenty-four 15-day-old male Hu lambs with similar birth weights were divided into two groups： control （12 lambs fed with a starter diet） and treatment （12 lambs fed with a starter diet containing cellulase at 0.1% w/v）. The experiment had a randomized group design. The test lambs were lactated with their mothers from 0 to 15 days of age， and then separated at 15 days of age and fed with milk replacer and kibble in a single pen. They were weaned at 60 days of age， and continued to feed freely on kibble after weaning. The experiment ended when the lambs reached 120 days of age. The main results were follows： 1） The body weight， average daily gain， and average daily feed intake of lambs were significantly higher in the treatment group than in the control group （P<0.05） at the pre-weaning stage； but significantly lower in the treatment group than in the control group （P<0.05） post-weaning. 2） At 60 days of age， the slaughter rate and lung index were significantly higher in the treatment group than in the control group （P<0.05）. At 120 days of age， the carcass weight and slaughter rate as well as heart indices were significantly higher in the control group than in the treatment group （P<0.05）. 3） At 60 days of age， the concentrations of butyric acid， myristic acid， and palmitic acid in the longissimus dorsi muscle were significantly higher in the control group than in the treatment group （P<0.05）， whereas the concentration of pentadecanoic acid was significantly lower in the control group than in the treatment group （P<0.05）. At 120 days of age， the heneicosanoic acid concentration was significantly higher in the control group than in the treatment group， and the lignoceric acid concentration was significantly lower in the control group than in the treatment group （P<0.05）. As lamb age increased， the concentrations of caproic acid， caprylic acid， undecenoic acid， myristic acid， pentadecanoic acid， arachidic acid， elaidic acid， and lignoceric acid significantly decreased in the control group； and those of pentadecanoic acid， elaidic acid， and lignoceric acid significantly decreased and that of palmitic acid significantly increased in the treatment group （P<0.05）. 4） At 60 days of age， the concentrations of myristoleic acid， palmitoleic acid， heptadecaenoic acid， oleic acid， γ-linolenic acid， and eicosapentaenoic acid （EPA） in the longissimus dorsi muscle were significantly higher in the control group than in the treatment group （P<0.05）. At 120 days of age， the concentration of myristoleic acid was significantly higher in the control group than in the treatment group （P<0.05）. From 60 to 120 days of age， in the control group， the concentrations of heptadecaenoic acid， eicossahexaenoic acid， arachidonic acid， EPA and docosahexaenoic acid （DHA） significantly decreased， and the concentration of myristoleic acid significantly increased； in the treatment group， the concentrations of monounsaturated fatty acids， myristoleic acid， palmitoleic acid， and oleic acid significantly increased （P<0.05）， and the concentrations of polyunsaturated fatty acids， linoleic acid， α-linolenic acid， eicosadienoic acid， eicossahexaenoic acid， epoxyeicosatrienoic acids， arachidonic acid， EPA and DHA significantly decreased （P<0.05）. 5） At 60 days of age， all indexes were significantly higher （P<0.05） in the control group than in the treatment group， except for the malondialdehyde concentration， which showed no significant difference. At 120 days of age， the values of all indexes were significantly higher in the treatment group than in the control group （P<0.05）， except for the superoxide dismutase concentration， which was significantly lower （P<0.05）. These results show that the addition of 0.1% cellulase to the starter diet improved the digestion， feed utilization， and slaughter performance of Hu lambs； it promoted fatty acid accumulation and affected fatty acid composition in muscle， which were beneficial to health pre-weaning， and improved antioxidant indices post-weaning.

Effects of exogenous additives on the rapid cultivation of moss crusts in alpine meadows of the Three-River-Source region， China

Long-xin GUO, Ming-yang ZHANG, Yong-sheng YANG, Bo PANG, Zhen-hua ZHANG, Xiu-juan ZHANG

2025, 34(7):  132-144.  DOI: 10.11686/cyxb2024327

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Establishment of moss crusts plays an important role in the conservation and restoration of alpine meadows in the Three-River-Source region. This research investigated methods for more rapid moss crust establishment. An orthogonal， full factorial experimentally design was used to investigate the effects of nutrient factors， a companion fungus and the plant growth regulator thidiazuron（TDZ） on the growth of moss crusts. It was found that： 1） The addition of the nutrient factor carbon （C） significantly inhibited the height of the moss crust， and the addition of nitrogen （N） and phosphorus （P） had significant effects on the coverage and height of the moss crust. 2） Fungus addition and TDZ supplementation resulted in significant increase in plant height of the moss crust （P<0.05）， and TDZ had an inhibitory effect on crust cover； 3） The interaction of TDZ with actinomyces had some positive effects on the cultivation of moss crust； 4） In the complete combination experiment， the optimal factor combination for rapid cultivation of alpine meadow in the Three-River-Source region was Bacillus megaterium （1 g·kg^-1 substrate）+distilled water. After 70 days growth in an artificial climate chamber under this treatment the moss crust cover was 90.35%， plant density was 31.39 plants·cm^-2， plant height was 1.86 mm and chlorophyll a content was 7.39 μg·cm^-2， respectively. In conclusion， the moss crust cultivation process in the Three-River-Source region was greatly affected by exogenous factors， and the growth was better with the addition of B. megaterium， which accelerated the establishment moss crust in this experiment.

Effects of simulated warming on photosynthesis of typical desert shrubs in the Hexi Corridor

Bin GUO, Wei-cheng LUO, Li-shan SHAN, Ning AN, Bing LIU

2025, 34(7):  145-157.  DOI: 10.11686/cyxb2024333

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With global climate warming， the climate in Northwest China is becoming increasingly warm and humid. This is significantly impacting plant growth and development， and physiological-ecological processes. However， the specific effect of climate warming on the photosynthesis of desert plants is still not fully understood. In this study， typical desert shrubs of the Hexi Corridor， including Nitraria sphaerocarpa， Haloxylon ammodendron， and Caragana korshinskii， along with the desert plant Tamarix ramosissima， were grown in open top chambers （OTCs） of varying heights （1.0， 1.8， and 2.3 m） to simulate increased temperatures， and the photosynthetic responses of these typical desert shrubs to warming were investigated. The results indicated that： 1） During the plant growing season （April to September）， the OTCs of 1.0， 1.8， and 2.3 m height increased the average air temperature by 1.7， 2.5， and 3.5 ℃， respectively； the soil temperature at 10 cm depth by 0.6， 1.2， and 1.8 ℃， respectively， and the soil temperature at 40 cm depth by 0.8， 1.2， and 1.8 ℃， respectively. 2） Warming significantly increased the net photosynthetic rate of the C₃ plants N. sphaerocarpa， T. ramosissima， and C. korshinskii， but had no significant effect on the C₄ plant H. ammodendron. Under increasing temperature， the net photosynthetic rate of C. korshinskii initially decreased before increasing. 3） Warming significantly increased stomatal conductance and the intercellular CO₂ concentration in N. sphaerocarpa， H. ammodendron， and C. korshinskii； however， in T. ramosissima， the stomatal conductance and intercellular CO₂ concentration initially increased before subsequently declining as the temperature increased. 4） Warming significantly increased the transpiration rate of H. ammodendron. The transpiration rate of C. korshinskii was increased only at the highest temperature， and that of T. ramosissima exhibited a significant decrease under increased temperatures. Warming did not significantly affect the transpiration rate of N. sphaerocarpa. Warming significantly enhanced the water use efficiency of N. sphaerocarpa， T. ramosissima， and C. korshinskii， but significantly reduced that of H. ammodendron. The predawn and midday water potentials of all four plant species were significantly reduced under warming conditions. In summary， these desert plants exhibited strong adaptability to warming， with C₄ plants demonstrating greater advantages over C₃ plants in the high-temperature environments. Under warming conditions， the increased transpiration rate and reduced water potential of the C₄ plant H. ammodendron facilitated its water absorption and stabilized photosynthesis， and the increase in stomatal conductance and intercellular CO₂ concentration promoted photosynthesis in the C₃ plants N. sphaerocarpa， T. ramosissima， and C. korshinskii.

Effects of drought stress and rehydration on biomass allocation and osmotic regulation characteristics of Indigofera bungeana

Jia-yi YONG, Shuang MA, Feng-hua MA, Xiao-na ZHAO, Yi-yin ZHANG, Hai-ying HU

2025, 34(7):  158-170.  DOI: 10.11686/cyxb2024330

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Plants under drought stress show various types of injury， and have adaptation strategies and repair processes that function during rehydration after drought stress. The degree of sensitivity to water deficit and the extent of recovery after rehydration differ among different plants. Therefore， it is of great significance to study drought tolerance and recovery after rehydration to breed drought-resistant and water-saving plants. In this research， a comparative analysis was conducted using wild and cultivated species of Indigofera bungeana. The plants were subjected to a drought stress treatment， imposed by controlling the water level in pots， followed by rehydration. Growth and physiological indexes were measured at 3， 6， 10， and 13 days of the drought stress treatment and at 2 and 7 days after rehydration. We explored the effects of drought stress and rehydration on biomass distribution to different organs， root distribution， and osmotic regulation， with an aim to analyze biomass allocation strategies and the physiological mechanisms of the drought response， and compared these characteristics between wild and cultivated I. bungeana. The main results of the study are as follows： 1） With prolonged drought stress， the organ biomass， root allocation characteristics （total root length， root surface area， root volume， root branches）， starch content， and activity of root neutral invertase （NIV） decreased， whereas the root-shoot ratio， the contents of proline， malondialdehyde （MDA）， and sucrose， and the activities of sucrose synthase， α-amylase， and leaf NIV gradually increased. 2） At 7 days after rehydration， except for root distribution and MDA content， all the other growth and physiological indexes returned to the control level， indicating that the plants were capable of compensatory growth after drought. 3） A principal component analysis based on all the indexes showed that the amplitude of the change in the indexes was significantly greater in the cultivated species than in the wild one， indicating that the cultivated species is more tolerant to drought stress. Under continuous drought stress， the two species of I. bungeana maintained turgor pressure by accumulating osmolarity-regulating substances， which alleviated damage to cell membranes. Moreover， the activity of sucrose- and starch-metabolizing enzymes was regulated to allocate biomass to the root system， and to provide energy to promote water absorption by the root system as adaptations to drought stress. Both species showed significant compensatory growth after rehydration.

Effects of drought stress and re-watering on the growth and physiological characteristics of Helianthus tuberosus seedlings

Hui-ling LI, Yong-xing ZHU, Meng CHEN, Shu LIU, Jiao WANG, Yi-qing LIU, Xue-mei ZHANG, Hui-hui MA

2025, 34(7):  171-184.  DOI: 10.11686/cyxb2024339

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The aim of this work was to clarify the response mechanism of Helianthus tuberosus seedlings to drought stress and re-watering. A pot experiment was conducted in which seedlings of H. tuberosus ‘Qingyu’ were subjected to a drought stress treatment （DS）， a control treatment during rewatering （RCK）， and a re-watering treatment （RW）. Seedlings in the control group （CK） were grown under normal （non-drought） conditions. The growth and physiological characteristics of the seedlings in the CK and treatment groups were measured. The growth morphology （total root length， root projected area， root surface area， average root diameter， number of root tips） and physiological parameters （photosynthesis parameters， chlorophyll fluorescence parameters， contents of photosynthetic pigments， water， saccharides， and osmoregulators， antioxidant enzyme activities， proline-metabolizing enzyme activities） of H. tuberosus seedlings were determined at 7， 14， 21， 28 days of drought stress and at 7 and 14 days of rewatering. The results showed that drought stress significantly inhibited the growth of H. tuberosus， but normal growth was restored by re-watering. Compared with plants in the DS group， those in the RW group showed significantly increased total root length， root surface area， root projected area， average diameter， and root tip number （by 18.18%， 54.36%， 30.35%， 34.51%， and 83.29%， respectively）， and higher chlorophyll a and chlorophyll a+b contents （increased by 19.51% and 19.42%， respectively）. Comparing the RW group with the DS group， the actual optical quantum efficiency and photochemical quenching coefficient were increased by 13.64% and 2.99% respectively， the free water content and relative water content were increased by 1250.00% and 1.34%， respectively， and the bound water content and total water content were increased by 12.84% and 8.99%， respectively. After the re-watering treatment， the water-absorbing ability of H. tuberosus seedlings was restored， allowing for normal growth to resume. Compared with the plants in the RCK group， significantly higher stomatal conductance， transpiration rate， and intercellular CO₂ concentration （increased by 90.27%， 52.24% and 44.75%， respectively） in the RW group； those in the RW group showed higher peroxidase activity and sucrose， fructose， and glucose contents on the 7th day， lower superoxide dismutase activity， catalase activity， proline and soluble protein contents， and higher activities of two enzymes in the proline synthesis pathway； Δ¹-pyrroline-5-carboxylic acid synthase and proline dehydrogenase. This promoted proline decomposition， contributing to the regulation of osmotic balance in H. tuberosus seedlings and the maintenance of normal cell turgor pressure. The results of this study provide a theoretical basis and reference for the practical application of water-saving cultivation techniques for H. tuberosus.

Effects of nitrogen， phosphorus and potassium rationing on production performance and nutritional quality of Echinochloa frumentacea in saline soil

Ling-fei XIANG, Feng-ju ZHANG, Dong-mei MA, Jin-long LIU, Jian LAN, Jian-qiang DENG, Hai-ying HU, Bin WANG, Chun-jiang CAI, Qiao-li MA

2025, 34(7):  185-195.  DOI: 10.11686/cyxb2024324

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The northern region of Ningxia has widely distributed saline and alkaline lands. Salinity， in turn， imposes limitations on use of land for crop and forage production， and such land typically has low soil fertility and low fertilizer response. These limitations seriously restrict the capacity for forage grass production in China. As a plant with wide adaptability and strong salinity tolerance， Hunan Jizi （Echinochloa frumentacea） is an important forage species for saline-alkaline land improvement and development of the forage and livestock industries. This experiment investigated the suitable fertilization rate for E. frumentacea on saline-alkaline land， using the ‘3414’ incomplete factorial experimental design to clarify the effects of different fertilization combinations of N， P and K on the production performance and nutritional quality of E. frumentacea. It was found that the average plant height of N₂P₁K₁ （N： 180 kg·ha^-1， P₂O₅： 45 kg·ha^-1， K₂O： 30 kg·ha^-1） was 1.58 m. The average yields of fresh herbage and hay in treatment N₂P₁K₁ were， respectively， 67.24% and 62.09% higher than those of the no-fertilizer treatment （P<0.05）. Nitrogen-phosphorus-potassium fertilizer application significantly increased the nutritive value of Hunan Jizi， and the treatments with the highest crude protein and crude ash contents were N₂P₀K₂ （N： 180 kg·ha^-1， P₂O₅： 0 kg·ha^-1， K₂O： 60 kg·ha^-1）， with gains of 5.77% and 8.75%， respectively， compared to no fertilizer. Meanwhile， the relative feeding value and dry matter digestibility， total digestible nutrients， and net lactation energy were all highest under treatment N₀P₂K₂ （N： 0 kg·ha^-1， P₂O₅： 90 kg·ha^-1， K₂O： 60 kg·ha^-1）. Multivariate principal component analysis indicated the highest overall ranking was obtained under the treatment N₂P₁K₁. Based on these results， the recommended fertilizer combination for growing Hunan Jizi on saline and alkaline land in northern Ningxia is： N 180 kg·ha^-1， P₂O₅ 45 kg·ha^-1， and K₂O 30 kg·ha^-1.

Seed germination and seedling growth characteristics of Glycyrrhiza uralensis from different provenances

Xiao-hong BAI, Wen-yan CHEN, Qin LI, Yi-xuan WANG, Xue ZHANG, Lei WANG, Wen-jie QU, Lin ZHU

2025, 34(7):  196-209.  DOI: 10.11686/cyxb2024313

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In this research a comparative study of seed germination and seedling growth characteristics of Glycyrrhiza uralensis germplasm lines of eight different provenances was conducted. It was found that there were significant differences in seed germination characteristics and seedling morphological characteristics among different accessions of G. uralensis （P<0.05）. The genetic diversity index ranged from 1.21 to 1.91， and the coefficient of variation ranged from 11.05% to 83.55%. Seeds from Yili were found to have higher germination rate at a range of different temperatures， indicating that they tolerate a wide range of germination temperatures. Seed length and width were significantly negatively correlated with seed germination rate and seed germination index （P≤0.01）. 1000-seed weight was significantly negatively correlated with seed germination vigor （P≤0.01）. Plant height was significantly positively correlated with seed germination rate （r=0.59， P≤0.01）. A multi-trait evaluation using a membership function method showed that the quality of seed lines from Chifeng provenance was the best， with a comprehensive evaluation D value of 0.89， followed by Huining and Hangjinqi， with comprehensive evaluation D values of 0.83 and 0.75， respectively. These three germplasm lines could therefore be used as high-quality resources for artificial breeding.

A review and prospect of ecological threshold

Bing-bing GAO, Xiao-man LIU, Jin-fang XIONG

2025, 34(7):  210-218.  DOI: 10.11686/cyxb2024389

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Ecological threshold is integral to the nonlinear dynamics of ecosystems. It is of great significance to explore the potential ecological threshold that can be breached to implement effective preventative strategies. Here， we review recent domestic and international research on ecological threshold， dissect the concept and development of ecological threshold， and discuss the advantages and disadvantages of the current ecological threshold identification methods. The application of ecological threshold is delineated to four main research domains： ecosystem conservation and restoration， global climate change mitigation， biodiversity conservation， and disaster prevention. The results of recent studies have revealed deficiencies in both theoretical and applied aspects of ecological threshold research. Building on this foundation， we propose priorities for further research on ecological threshold in China. This review offers insights and references for the conservation， restoration， and sustainable development of China’s ecosystems.

Research progress on yield loss under drought stress and drought resistance genetics of alfalfa （Medicago sativa）

Xue-qian JIANG, Qing-chuan YANG, Jun-mei KANG

2025, 34(7):  219-234.  DOI: 10.11686/cyxb2024344

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Alfalfa （Medicago sativa） is the most widely cultivated perennial leguminous forage crop， acclaimed as the “king of forages” because of its high yield and superior quality. Drought stress has a significant impact on the growth and development of alfalfa， resulting in substantial yield reductions. It influences the germination rate， branch formation， stem elongation， leaf growth， and root development， potentially causing large decreases （>70%） in forage yield. Accelerating the breeding of drought-tolerant alfalfa varieties through molecular breeding is an effective strategy to mitigate the effects of drought stress on this forage crop. However， the genetic foundation of drought resistance in alfalfa remains largely unexplored. Previous research on alfalfa has mainly concentrated on transgenic methods and homologous cloning techniques. With the release of the alfalfa genome and advances in sequencing technology， genome-wide association studies and omics technologies based on transcriptome sequencing have played an increasingly important role in identifying drought-related genes and elucidating drought resistance mechanisms in alfalfa. This paper comprehensively summarizes the effects of drought stress on alfalfa yield， outlines recent advances in research on the genetic basis of drought resistance in alfalfa， and provides a reference for the breeding of drought-resistant alfalfa varieties.