Table of Content

20 December 2025, Volume 34 Issue 12

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Impacts of shrub encroachment on the fraction and stability of soil organic carbon of grassland on the Loess Plateau， and the underlying microbial mechanisms

Yu-du JING, Xiao-wei LIU, Ke LIANG, Jun-hao FENG, Qiang YU, Liang GUO

2025, 34(12):  1-15.  DOI: 10.11686/cyxb2025034

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Shrub encroachment is significantly affecting carbon cycling in grassland ecosystems worldwide， yet its impact on the components and stability of grassland soil organic carbon， and particularly the underlying microbial regulatory mechanisms， remains insufficiently studied. In this study， we focused on the semi-arid grassland of the central Loess Plateau， and analyzed the effects of shrub encroachment on various soil physicochemical and biological properties， organic carbon components and their proportions， microbial community structure， functions， and trophic types， as well as the underlying microbial regulatory mechanisms. The results show that shrub encroachment significantly increased the total organic carbon， dissolved organic carbon， mineral-associated organic carbon （MAOC）， and particulate organic carbon （POC） contents in soil， and the relative proportion of MAOC， but significantly decreased the relative proportion of POC. Furthermore， shrub encroachment significantly altered the bacterial and fungal community composition by affecting soil physicochemical properties， with different impacts on the relative abundance of amplicon sequence variants of different phyla. Shrub encroachment enhanced soil bacterial nitrification， sulfur oxidation， and iron respiration functions， as well as the abundance of fungal saprotrophic and woody saprotrophic type functions， but reduced the abundance of bacterial methylotrophy and aromatic compound degradation functions. The soil microbial residue carbon and bacterial functions were significantly correlated with the contents and proportions of POC and MAOC. A partial least squares path analysis showed that extracellular enzyme activity and microbial residue carbon， related to carbon cycling， were the microbial factors directly regulating the contents and relative proportions of soil organic carbon components， whereas microbial community composition influenced these processes indirectly. These results indicate that shrub encroachment not only increases the total amount of soil carbon and the contents of soil organic carbon components in grassland soils， but also significantly enhances the stability of the soil carbon pool， with extracellular enzymes secreted by soil microbes and microbial residue carbon playing crucial regulatory roles. The findings of this study provide new information about the mechanisms by which microbes regulate organic carbon components in grassland soils under shrub encroachment. These results provide theoretical support for predicting future changes in the soil carbon pool of shrub-encroached grassland on the Loess Plateau.

Diversity of microorganisms in the rhizosphere soil of Kobresia humilis and their responses to environmental factors in the source region of the Yellow River

Hui-yun TAO, Run-yan YANG, Yan-can LI, Ya-peng LIU, He-xing QI

2025, 34(12):  16-32.  DOI: 10.11686/cyxb2025036

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In this study， we explored the relationships between environmental factors and microbial diversity/community structure in the rhizosphere soil of Kobresia humilis. Rhizosphere soil samples were collected from K. humilis growing at sites in the source area of the Yellow River within an altitude range of 3000-5000 m. Environmental factors were recorded at each site， and soil samples were analyzed to determine the composition of the rhizosphere soil microbial community. Illumina MiSeq sequencing and bioinformatics analysis were conducted to identify and classify the fungi and bacteria in the rhizosphere soil samples. The results show that the relationships between microbial diversity/community structure and environmental factors differed among five different altitudes in the source region of the Yellow River. Among the rhizosphere soils collected at different altitudes， the soil collected at 4027.0 m had the highest fungal diversity and the soil collected at 4932.1 m had the highest bacterial diversity， indicating that fungi and bacteria showed different responses to altitude. Soil microbial community structure differed with elevation： the abundance of Olpidiomycota in the fungal community increased with elevation， and Basidiobolomycota was only found at sampling sites higher than 4500 m. The taxa Nitrospirota， Bdellovibrionota， Elusimicrobiota， RCP2-54， and SAR324_cladeMarine_group_B showed increased abundance with increasing altitude， whereas the abundance of Fusobacteriota gradually declined with increasing altitude. The soil pH decreased with increasing altitude， but other soil physicochemical factors showed more complex changes with altitude. The pH， total phosphorus， available nitrogen， and organic carbon contents in soil collected at 4932.1 m were significantly different from those in soils collected at other altitudes （P<0.05）. The total potassium， available phosphorus， and available potassium contents in soil collected at 4027.0 m were significantly different from those in soils collected at other altitudes （P<0.05）. A redundancy analysis showed that available potassium and altitude were important factors affecting the composition and diversity of fungi， while the bacterial community was more strongly affected by pH， total nitrogen， total phosphorus， available nitrogen， organic carbon， and altitude. Among those factors， soil pH had the most significant effect on bacterial community structure. In this study， Illumina MiSeq sequencing technology was used to analyze soil microbial diversity and community structure in the rhizosphere of K. humilis at different altitudes， and the effects of environmental factors on the rhizosphere microbial community were determined. The results provide a theoretical basis for ecological protection at the soil microbe level in the source region of the Yellow River.

Carbon and water fluxes of different grassland types in the growing season based on the Common Land Model

Yang CHENG, Chang-qing JING

2025, 34(12):  33-49.  DOI: 10.11686/cyxb2025004

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Grassland ecosystems occupy the largest area among the terrestrial ecosystems in China， and their carbon and water fluxes play an important role in the land-air carbon and energy cycles. In this study， we optimized the root water uptake function （RWUF） and soil respiration function （SRF） of a Common Land Model， evaluated the applicability of the model to the simulation of carbon and water flux in different grassland ecosystems， simulated and analyzed trends in the seasonal and daily variation of carbon and water flux in different grassland types， and discussed the key factors influencing water and carbon processes in different grassland types. It was found that the Common Land Model was suitable for simulating carbon and water fluxes in different grassland ecosystems during the growing season， and the simulation results of evapotranspiration （ET） were better than those of carbon fluxes （gross primary productivity， ecosystem respiration， net ecosystem exchange）. The total evapotranspiration of temperate desert， temperate steppe， desert steppe and mountain meadow in the growing season is greater than precipitation， and the carbon uptake of temperate steppe， desert steppe and mountain meadow in the growing season is -28.2， -41.5， and -152.0 g C·m^-2， respectively， showing carbon fixation and carbon sequestration capacity ranking as： Mountain meadow>desert steppe>temperate steppe. Precipitation and net radiation were the most important factors affecting evapotranspiration of different grassland types during the growing season， and were significantly positively correlated with carbon and water flux （P<0.01）. With low vegetation cover in arid land， evapotranspiration was more significantly affected by soil evaporation than was the case with grassland， and evapotranspiration of grassland with good vegetation cover was more affected by plant transpiration. Leaf area index （LAI） was the most important factor affecting carbon exchange in grassland ecosystems， followed by precipitation and net radiation. This study provides a framework for understanding the carbon and water cycling processes of grassland ecosystems and their responses to climate change in arid and semi-arid areas.

Biodiversity and phylogenetic diversity of grasslands in the Habahe forest area of Xinjiang and analysis of the influencing factors

Ye-xin LYU, Mao YE, Jiao-rong QIAN, Wei-long CHEN, Jing CHE, Miao-miao LI, Guo-yan ZENG

2025, 34(12):  50-61.  DOI: 10.11686/cyxb2025106

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In this work， we examined the mechanisms driving grassland community assembly in the Habahe forest region. In total， 117 quadrats were established， and the herbaceous plant community was analyzed on the basis of biodiversity indicators such as species composition and phylogenetic structure. Pearson’s correlation and generalized linear model （GLM） analyses were utilized to explore relationships among biodiversity metrics and to evaluate the impacts of environmental factors on community structure. The main results were as follows： 1） The plant community comprised 42 herbaceous species belonging to 17 families and 37 genera， with Poaceae， Asteraceae， Rosaceae， and Ranunculaceae being the dominant families. Setaria viridis， Poa annua， Alchemilla japonica， and Stipa capillata were the primary dominant species； 2） The values of the net relatedness index （NRI） and net nearest taxa index （NTI） were above zero in 61.5% of the plots examined， with the independent-samples t-test （T） indicating significant phylogenetic clustering patterns （P<0.05）； 3） Phylogenetic diversity index （PD） showed significant positive correlations （P<0.001） with the Margalef diversity index （Ma）， Shannon-Wiener diversity index （H′）， Simpson’s dominance index （D）， and species richness （SR）. In contrast， both the NRI and NTI were negatively correlated （P<0.05） with H′ and D； 4） The results of the GLM analysis revealed that mean annual precipitation positively influenced species diversity indices and NTI （P<0.05）. Species diversity indices exhibited robust positive associations with longitude and elevation （P<0.001）， but significant negative correlations with latitude （P<0.05）. Mean annual temperature was significantly and negatively correlated with Ma （P<0.05） and H′ （P<0.001）. Notably， environmental factors did not show significant effects on PD or NRI （P>0.05）. These results suggest that moisture availability and geographic gradients play crucial roles in shaping the patterns of grassland community diversity in this particular region.

Grazing exclusion modifies the relationship between plant community diversity and aboveground biomass in the Qiangtang grassland

Chen-xu LIU, Yan-tao SONG, Lei SUN, Tao PENG, Wuyunna

2025, 34(12):  62-72.  DOI: 10.11686/cyxb2025021

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Grazing exclusion is one of the effective measures for restoring degraded grassland ecosystems. The aim of this study was to examine the effect of fencing for various periods on grassland plant communities in the Qiangtang grassland. A field study was conducted in Nagqu City， Bangor County， where grassland plots enclosed for 5， 9， 13， 17， and 21 years were selected for analysis， with freely-grazed areas outside the enclosures as the control plots. We assessed the effects of enclosure and free-grazing practices on plant community characteristics， plant community diversity， and their relationships by analysis of variance， regression analysis， and correlation analysis. The results indicate that enclosure increased the importance value of the dominant species， Stipa purpurea. Varying levels of enhancement in aboveground biomass （AGB）， coverage， height， and density were observed after different periods of enclosure， with significant differences detected between the free-grazed and enclosed plots after 9 and 21 years （P<0.05）. Notably， the alpha diversity of the plant community was significantly lower in enclosed plots than in free-grazed plots after 9 years of enclosure （P<0.05）. Following initial grazing exclusion， the relationship between AGB and plant community diversity underwent a pronounced shift. In non-enclosed （grazed） areas， AGB and diversity indices exhibited a positive， albeit non-significant correlation （P>0.05）. Conversely， within the enclosures， AGB and diversity indices showed statistically significant negative correlations （P<0.05）. These results collectively indicate that enclosure for 9 years optimizes grassland management outcomes for the Qiangtang grassland. Crucially， the post-enclosure increases in the AGB of the dominant species （S. purpurea） serve as the primary mechanistic driver underlying the change in the AGB-diversity relationship， consistent with the mass ratio hypothesis.

Identification of areas of Aconitum leucostomum incursion and monitoring of grassland degradation in the Tuohulasu grassland of Xinjiang based on multi feature fusion

Long YIN, Qi-fei HAN, Yang ZHAO, Wen-xin LIU

2025, 34(12):  73-84.  DOI: 10.11686/cyxb2025024

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Land degradation through colonization by poisonous weeds does not exhibit typical land degradation characteristics such as bare ground or reduced plant biomass， making large-scale remote sensing identification of colonized areas challenging. Texture features and temporal characteristics， as important derivatives of remote sensing images， provide more detailed information on land cover， reducing the ambiguities sometimes referred to as “same object， different spectra” and “same spectra， different objects”. Information from these texture features can significantly improve classification accuracy and reliability. This study focuses on the Tuohulasu grassland in the Ili River Valley， using Sentinel-2 satellite data to extract features indicating presence of the toxic weed Aconitum leucostomum. Based on pixel-scale identification， the distribution range of A. leucostomum was determined， and its proportion in mixed pixels was calculated. Finally， the vegetation cover after excluding A. leucostomum was calculated to analyze the grassland degradation trends in the Tuohulasu grassland from 2018 to 2024. The results show that： 1） Feature selection effectively reduces information redundancy， and the combination of spectral and texture features effectively improves classification accuracy （overall accuracy 91.67%， Kappa coefficient 0.83）. 2） A. leucostomum is mainly distributed in the flat areas of sunny slopes and river valleys. A. leucostomum was found in 40% of the study area， with sparse cover （0-0.25%） as the most common scenario. From 2018 to 2024， the distribution of various density levels has changed by 0.67%-1.17%. 3） After correction， the grassland degradation index changed from mild to moderate between 2018 and 2024， but the proportion of non-degraded areas increased by 1.17%， while the areas with moderate and severe degradation decreased by 1.15% and 0.70%， respectively. This study provides important methodological support for large-scale identification of toxic weeds and monitoring of grassland degradation based on multispectral data.

Use of spectral index-assisted machine learning to improve the accuracy of maize leaf water content estimation

Ya-ting XIAO, Yu-zhe TANG, Lu WANG, Yu-fei BAI, Hai-bo YANG, Fei LI

2025, 34(12):  85-96.  DOI: 10.11686/cyxb2025033

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Rapid and non-destructive monitoring of the water status of maize （Zea mays） is important for water status diagnosis and irrigation management. Spectral indices serve as crucial tools for non-destructive real-time estimation of crop leaf water content （LWC）. However， traditional spectral indices are sensitive to external environmental factors， resulting in reduced prediction accuracy when they are used to estimate LWC. Machine learning （ML） algorithms demonstrate distinct advantages in predicting crop water status， particularly when applied in precision agriculture and crop water status monitoring. Therefore the aims of this study were to enhance the accuracy of LWC estimation by integrating spectral indices with ML approaches， with an overall goal to facilitate efficient water resource utilization during maize cultivation. Field experiments with varying water gradients were conducted in typical maize cultivation regions of Inner Mongolia during 2023-2024. The hyperspectral reflectance of maize leaves were measured across three critical growth stages， and then correlation analyses were conducted between maize LWC and 13 water-sensitive spectral indices. To develop LWC estimation models， spectral features selected via the ReliefF technique were used as input variables for three ML algorithms-partial least squares regression （PLSR）， random forest （RF）， and Gaussian process regression （GPR）. The results demonstrate that among the 13 hydrological indices， the modified DATT index exhibited optimal predictive performance （coefficient of determination R2=0.52）. However， its accuracy was affected by the growth stage and leaf canopy position， limiting its effectiveness for LWC monitoring. Integrating full-spectrum data （350-2500 nm） with ReliefF-selected spectral indices into ML algorithms enhanced the accuracy of LWC estimates by 7%-45%. Models utilizing spectral indices as input features demonstrated superior overall performance， with the RF and GPR models explaining 88%-89% of LWC variability. Independent validations confirmed the robustness of the models， with coefficient of determination R2 values of 0.89 （RF） and 0.88 （GPR） and root mean square error values of 1.95% and 2.04%. Our results show that the synergistic combination of spectral indices with RF/GPR algorithms had cascading effects， significantly improving the accuracy of LWC estimation. This methodology provides a reliable approach for monitoring maize water status and establishes a scientific foundation for the development of precise integrated water-fertilizer management systems.

Effects of mixed cropping of leguminous forage and reduced nitrogen fertilizer on soil physicochemical properties and forage yield in a silage maize production system

Di-cheng WANG, Qiang CHAI, Zhi-long FAN, Wen YIN, Hong FAN, Wei HE, Ya-li SUN, Hui-zhe SANG, Fa-long HU

2025, 34(12):  97-110.  DOI: 10.11686/cyxb2024527

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In response to the issues of high nitrogen fertilizer input and declining soil quality in the Hexi Oasis irrigation area for silage maize （Zea mays） production， this study investigated the effects of mixed leguminous forages on soil physicochemical properties and yield of silage maize under reduced nitrogen supply. The aim was to provide a scientific basis and theoretical support for development of recommendations for soil health management and sustainable production of silage maize in this region. The experiment was conducted at the Wuwei Oasis Agricultural Comprehensive Experimental Station from 2023 to 2024 using a split-plot design. The main plots consisted of three crop planting patterns ［M： monoculture of silage maize； MH： mixed of silage maize and soybean （Glycine max）； ML： mixed of silage maize and lablab bean （Dolichos lablab）］， while the subplots comprised three nitrogen application levels （N₃： 360 kg·ha^-1； N₂： 306 kg·ha^-1； N₁： 252 kg·ha^-1）. The results showed that compared to the M planting pattern with a 30% reduction in nitrogen fertilizer， the soil bulk density in MH and ML patterns under the same nitrogen level was reduced by 5.5% and 8.0%， respectively； porosity was increased by 6.6% and 10.8%， respectively； pH was decreased by 0.9% and 1.0%， respectively； organic matter was increased by 3.9% and 5.1%， respectively； total nitrogen content was increased by 9.2% and 10.4%， respectively； total phosphorus content was increased by 8.7% and 10.9%， respectively； total potassium content was increased by 9.4% and 12.0%， respectively； nitrate nitrogen content was increased by 26.4% and 29.8%， respectively； ammonium nitrogen content was increased by 19.1% and 25.1%， respectively； available phosphorus content was increased by 8.8% and 10.6%， respectively； and available potassium content was increased by 5.7% and 10.1%， respectively. In addition， compared to the M planting pattern， the forage yield and energy yield in the MH planting pattern were increased by 23.1% and 25.2%， respectively， and in the ML planting pattern by 30.5% and 33.6%， respectively. Under the MH planting pattern with a 30% reduction in nitrogen， the forage yield and energy yield did not differ significantly from traditional nitrogen application， but under the ML pattern， they were increased by 20.5% and 17.8%， respectively. Moreover， the forage yield and energy yield in the MH planting pattern with a 30% reduction in nitrogen were increased by 15.8% and 17.8%， respectively， compared to the traditional nitrogen application in the M planting pattern， and in the ML pattern with a 30% reduction in nitrogen， they were increased by 23.8% and 28.6%， respectively. Therefore， ML patten combined with a nitrogen application rate of 252 kg·ha^-1 improved soil physicochemical properties and increased forage yield， and can be recommended as a suitable cropping pattern and nitrogen rate for silage maize production in the oasis irrigation area.

Effect of the mix-ratio of corn stalk and edamame stems/leaves and added cellulase on the fermentation quality and microbial community of silage

Jun-ling WEI, Xiao-qi LIU, Wan-qing WANG, Ming DENG, Bao-li SUN, Yong-qing GUO

2025, 34(12):  111-120.  DOI: 10.11686/cyxb2025007

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The effects of cellulase on silage quality and microbial diversity of corn （Zea mays） stalk and edamame （Glycine max） stems and leaves were investigated. The ratios of corn stalk and edamame stems and leaves by weight were 1∶0， 3∶1， and 1∶1 （10， 31， 11）. Each mixture ratio was divided into a control group （CS） and a cellulase group ［CS（c）， adding 0.1%］. The nutrient composition， fermentation quality and microbial diversity of silage was evaluated after 80 days. It was found that the 3∶1 mix-ratio of corn stalk and edamame stems and leaves resulted in better silage quality than the other two mix-ratios. As the proportion of edamame stems and leaves increased， the pH， ammonia nitrogen content， and crude protein content of the mixed silage significantly increased （P<0.05）， while the water-soluble carbohydrate， neutral detergent fiber and acid detergent fiber （ADF） were significantly decreased （P<0.05）. The lactic acid content was higher for CS31 than for CS10 or CS11. The addition of cellulase had no significant effect on the fermentation parameters of silage at a given mix-ratio （P>0.05）， but tended to reduce the ADF content （P=0.07）. Furthermore， the addition of edamame stems and leaves increased the relative abundance of Firmicutes and Lactobacillus while reducing the relative abundance of Proteobacteria in the mixed silage. In conclusion， the mixed silage CS31， with a 3∶1 of corn stalk to edamame stems and leaves exhibited superior quality compared to other ratios， and the addition of cellulase improved the fermentation quality of the mixed silage.

Responses of maize dry matter accumulation， translocation and grain yield to potassium application rates under drip irrigation conditions in the arid areas of Northwest China

Zi-qiang HONG, Zheng-zhen ZHANG, Ming SU, Fan-guo LI, Tian ZHOU, Hong-liang WU, Jian-hong KANG

2025, 34(12):  121-133.  DOI: 10.11686/cyxb2025019

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This research aimed to provide scientific and technical data to support high-yield and high-efficiency of maize cultivation in the arid region of Ningxia and investigated the effects of potassium application rates on dry matter accumulation， transport， and yield formation of maize （Zea mays） under drip irrigation. A randomized block trial was conducted in 2022 and 2023 at Pingjipu Farm， Yinchuan， Ningxia， China. The trial included six potassium fertilizer treatments： 0 （K₀）， 60 （K₁）， 120 （K₂）， 180 （K₃）， 240 （K₄）， and 300 kg·ha^-1 （K₅）. Appropriate potassium supplementation significantly enhanced dry matter accumulation and improved both pre- and post-anthesis substrate translocation efficiency， thereby establishing the foundation for yield improvement. The K₃ treatment achieved maximum dry matter accumulation of 37826 kg·ha^-1 in 2022 and 36610 kg·ha^-1 in 2023. These values significantly exceeded those of other treatments by 6.53%-23.12% and 3.62%-18.79%， respectively. The pre-anthesis dry matter translocation contribution rate under the K₃ treatment was 14.84%-81.87% （2022） and 5.61%-25.84% （2023） higher than other treatments. Post-anthesis dry matter accumulation in K₃ increased by 7.13%-17.44% （P<0.05） and 1.48%-16.33% across the two years. Compared with K₀， K₃ exhibited 20.63% （2022） and 18.47% （2023） higher biomass at maximum biomass accumulation. The maximum dry matter accumulation rate under K₃ surpassed other treatments by 4.42%-37.21% （2022） and 1.52%-18.24% （2023）， while the mean accumulation rate increased by 6.60%-40.50% and 4.25%-22.74%， in 2022 and 2023， respectively. The K₃ treatment also achieved the highest mean crop growth rate （CGR）， exceeding other treatments by 4.75%-26.36% and 2.93%-17.16% in 2022 and 2023， respectively. Maize yield initially increased then decreased with increasing potassium application rates， peaking under K₃ at 15179 kg·ha^-1 （2022） and 14944 kg·ha^-1 （2023）， corresponding to average yield improvements of 2.29%-18.07% and 4.32%-28.24%， respectively， over other treatments. Path analysis revealed that under high-density planting conditions， prioritizing enhancement of 100-grain weight， followed by ear number and kernel number per ear could further boost yields. Quadratic regression analysis identified optimal economic potassium rates of 167.25 kg·ha^-1 （2022） and 170.66 kg·ha^-1 （2023）. Integrated analysis therefore demonstrates that the recommended optimal economic potassium application rate for maize in arid regions of Ningxia ranges from 167 to 180 kg·ha^-1， thereby achieving the dual objectives of high-yield and resource-efficient cultivation.

Differences in leaf traits between invasive and native species of Asteraceae

Ting-ting LIU, Jin-sheng LI, Jian-hua LIN, Dan-dan ZHANG, Wen-yu JIANG, Xu-rui ZHU, Zhen ZHANG

2025, 34(12):  134-144.  DOI: 10.11686/cyxb2025009

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Given the changes in the structure and composition of native plant communities caused by invasive species， along with their detrimental effects on biodiversity， this paper aims to investigate the differences in leaf anatomical structures and physiological and chemical traits between invasive plants and native plants of the Asteraceae family. The invasive species Solidago canadensis， Sonchus oleraceus， Erigeron annuus and the native species Lactuca indica， Cirsium setosum were selected as representative species to determine if there are systematic leaf anatomical structure and physiological and chemical trait differences between invasive and native Asteraceae species. The results indicated that invasive plants exhibited a higher average cuticle thickness， palisade-sponge ratio， and cell tightness ratio compared to native plants. This suggests that invasive plants possess superior water retention ability and stress adaptability， compared to their native species counterparts. Furthermore， invasive species exhibit greater potential for photosynthesis and nutrient acquisition compared to native species， as evidenced by higher chlorophyll content， specific leaf area， and total nitrogen content than the native Asteraceae species. In addition， the results of redundancy analysis reveal a significant relationship between the anatomical structure of leaves and their physiological and chemical traits. Specifically， an increase in leaf thickness generally indicates greater light absorption， which enhances the photosynthetic efficiency of the leaves. Consequently， it is these advantageous characteristics that have enabled the invasive species to proliferate and colonize successfully.

Dynamic changes in pigment contents and photosynthetic characteristics of grains of black-grained and yellow-grained oat （Avena sativa）

Ze-long HU, Guo-ling LIANG, Wen-hui LIU, Wen-hu WANG

2025, 34(12):  145-156.  DOI: 10.11686/cyxb2025028

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The aim of this work was to analyze and compare the changes in photosynthetic characteristics and pigment contents in grains between black-grained and yellow-grained oat （Avena sativa） during grain development. We monitored the dynamic changes in photosynthetic traits and the contents of photosynthetic pigments， anthocyanins， and melanin， as well as the activities of anthocyanin-synthesizing enzymes， in grains of black-grained and yellow-grained oat from heading to maturity. The results show that the lemma colors of the two oat types significantly diverged during development. Starting from 20 days after heading， the lemma of yellow-grained oats gradually turned yellow， while that of black-grained oats turned black. These patterns of color development were highly consistent with the accumulation patterns of anthocyanins and melanin. During the mid-development stage （20-30 days after heading）， compared with black-grained oats， the yellow-grained oats had significantly higher （P<0.01） contents of photosynthetic pigments and higher net photosynthetic rate （P_n）， stomatal conductance， and transpiration rate. However， at the flowering and milky ripening stages， the daily P_n of yellow-grained oats showed a bimodal pattern with a distinct “midday depression” phenomenon. In contrast， black-grained oat grains began to accumulate anthocyanins and melanin continuously from 15 days after heading. By maturity， the anthocyanin and melanin contents of black-grained oats were 83.96% higher and 39.8-times higher， respectively， than those of yellow-grained oats. In black-grained oats， the daily pattern of P_n was unimodal without photoinhibition. Structural equation modeling indicated that grain color had the greatest comprehensive impact on P_n， with photosynthetic pigments positively affecting the photosynthetic rate and anthocyanins and melanin negatively affecting it. The results of this study provide a scientific basis for breeding new oat varieties with strong adaptability and high photosynthetic efficiency.

Cloning of the gene ZjWRKY63 from Zoysia japonica and its salt resistance analysis in transgenic Arabidopsis

Yong-long LI, Sheng-hui ZHOU, Meng-yao XUE, Yuan GAO, Le JU, Yi-bing CHEN, Song-lin FU, Jian-hao HAO, Heng LI, Kun ZHANG, Zhi-fang ZUO

2025, 34(12):  157-169.  DOI: 10.11686/cyxb2025014

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WRKY transcription factors play crucial regulatory roles in plant growth and development， pathogen defense， and responses to abiotic stress. Based on the previous gene family identification of WRKY transcription factor genes in Zoysia japonica， as well as the transcriptome analysis of the salt-tolerant and salt-sensitive Z. japonica species under salt stress， a salt stress-responsive WRKY transcription factor gene named ZjWRKY63 was screened out. To further investigate the salt-tolerance function of this gene， primers were designed for PCR amplification， and the coding sequence （CDS） with an open reading frame of 921 bp was cloned. The ZjWRKY63 encodes a protein containing 306 amino acids， which possesses one WRKY functional conserved domain and one C₂H₂ zinc finger structural motif， and belongs to theWRKY IIa subfamily. Bioinformatics analysis revealed that the maximum score value of the average signal peptide for the amino acid residues of ZjWRKY63 was 0.267， indicating that this protein does not possess a signal peptide. Hydrophobicity prediction analysis showed that the grand average of hydrophobicity （GRAVY） value was -0.395， indicating that this protein is a hydrophilic protein. Transmembrane region prediction found no transmembrane region in ZjWRKY63. Prediction of subcellular localization showed that ZjWRKY63 would be localized in the nucleus. Phylogenetic analysis demonstrated that ZjWRKY63 of Z. japonica has the closest genetic relationship with the Persea americana， PaWRKY65. Salt stress treatment was conducted using the seeds and plants of transgenic Arabidopsis thaliana with overexpressed ZjWRKY63. It was found that the seed germination rate， survival rate and number of lateral roots of the overexpressing plants were significantly higher than those of the wild type. Meanwhile， in the transgenic A. thaliana with ZjWRKY63， the expression of genes related to salt stress response was significantly higher than that in the wild type in all cases. We speculate that the ZjWRKY63 gene enhances the salt tolerance of transgenic A. thaliana by regulating the expression of stress response genes. The above research results provide preliminary confirmation of the salt-tolerance function of the ZjWRKY63 gene， and lay a scientific foundation for further investigation of the molecular mechanism of the salt-tolerance conferred by the ZjWRKY63 gene.

Population genetic diversity and genetic structure analysis of Littledalea przevalskyi based on SSR molecular marker

Gui FU, Yu-ping LIU, Xu SU, Rong-ju QU, Cairangzhaxi

2025, 34(12):  170-182.  DOI: 10.11686/cyxb2025012

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Littledalea przevalskyi is a member of the grass family （Poaceae） with significant ecological and economic value and with a geographic distribution including Inner Mongolia and the Qinghai-Tibetan Plateau. This research investigated the genetic diversity， genetic structure， and species distribution patterns of L. przevalskyi. The L. przevalskyi populations studied originated from 21 different regions and the genomic investigation was based on 15 pairs of simple sequence repeats （SSR） primers. A total of 147 alleles （Na） were detected by the 15 primer pairs， the average number of alleles was 9.8， the average effective allele per SSR marker （Ne） was 5.418， the average Shannon’s information index （I） was 1.808， the average expected heterozygosity （He） was 0.791， the average observed heterozygosity （Ho） was 0.882， and Nei’s gene diversity index（H） was 0.785. The polymorphism information content （PIC） of the 15 primer pairs ranged from 0.530 to 0.900 with a mean value of 0.756. The results of species level genetic diversity showed that 15 polymorphic loci were detected in the 21 populations. The average polymorphic loci was 13.57， and the average values of Na， Ne， I， He， Ho， and H were 3.299， 2.806， 1.028， 0.717， 0.841， and 0.598， respectively. The results of coefficient of genetic differentiation and gene flow quantification showed a certain degree of genetic differentiation among the L. przevalskyi populations. Analysis of molecular variance （AMOVA） revealed that 33% of total genetic variation occurred among populations， while 67% resided within populations. Integrated analysis of cluster analysis， principal component analysis （PCA）， and genetic structure analysis revealed that the genotype of samples derived from different distribution areas had significant differences. Based on the geographical origins of the samples， the 21 population samples can be roughly classified into two subgroups， the southeastern populations （subgroup I） primarily consisting of originating from Maduo， Maqin， southeastern Qumalai， Yushu， and Riwoqê， and the northwestern populations （subgroup Ⅱ） mainly including those originating from Geermu， northwestern Qumalai， and Chenduo. A Mantel test showed there was a significant correlation between genetic distance and geographical distance （r=0.412； P<0.001）， implying the genetic differentiation among different populations may be related to geographical barriers. The results of this study provide a theoretical and quantitative basis for exploring and categorizing the phylogenetic relationships， species definition， germplasm resource evaluation， and conservation and utilization of wild resources of the genus Littledalea.

Efficient transformation of Pennisetum alopecuroides using pollen transfected by DNA-coated magnetic nanoparticles

Yu-wan WANG, Ling-yun LIU, Yi-di GUO, Xi-feng FAN, Yue-sen YUE, Na MU, Guo-zeng XIAO, Ke TENG

2025, 34(12):  183-194.  DOI: 10.11686/cyxb2025047

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In recent years， nanoparticle-mediated gene transformation has overcome the problem of traditional transgenic methods that require tissue regeneration and culture. This method shortens the cultivation cycle of transgenic plants， and has a wide range of applications. No mature genetic transformation systems are available forthe grass Pennisetum alopecuroides， so the aim of this study was to develop a nano-magnetic bead-mediated transformation system for this plant. The P. alopecuroides ‘Liqiu’ was used to optimize the key steps including transfection temperature and processing time， nanomagnetic bead loading capacity， and the hybridization and screening of transgenic lines. The results showed that the vitality of P. alopecuroides pollen was higher after treatments at 4 and 8 °C than after treatments at 12， 16， and 25 °C. There was no siginificant difference in the pollen opening rate between 0.5 and 2 hours of transfection time， and pollen vitality was not affected by the duration of the transfection time. Accordingly， 0.5 hours was selected as the transfection time. The transfected pollen was used to pollinate P. alopecuroides ‘Liqiu’， and 150 seeds were randomly selected from the naturally obtained hybrid seeds. Transgenic seedlings were screened on medium containing 80 mg·L^-1 hygromycin. Subsequently， PCR detection and green fluorescent protein observation results confirmed that seven transgenic plants had been obtained. In summary， a pollen tube channel transformation system based on DNA-coated nanomagnetic beads was established for P. alopecuroides. Our results show that transgenic seedlings can be generated within 5 months with a transformation rate of about 4.66%. This system represents a new solution for genetic transformation and molecular improvement of P. alopecuroides in the future.

Effect of co-attack of spring black stem and leaf spot disease and aphids on the yield and forage value of alfalfa

Mei-ting BAI, Ying-de LI, Qian-hua CHEN, Yan-li FENG, Hai-ming FENG, Ting-yu DUAN

2025, 34(12):  195-205.  DOI: 10.11686/cyxb2025094

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Pests and diseases significantly constrain Medicago sativa （alfalfa） production. Spring black stem disease， caused by the fungal pathogen Phoma medicagonis and pea aphid （Acyrthosiphon pisum）， is widespread in alfalfa-growing regions of China. However， the impact of the combined occurrence of this pathogen and the aphid on alfalfa yield and quality remains unclear. To address this knowledge gap， we conducted a field experiment at the Jingtai Field Scientific Observation and Research Station of Grassland Agro-Ecosystems， Lanzhou University. The treatments included spring black stem inoculation， pea aphid disease infestation， combined spring black stem disease inoculation and pea aphid infestation， and spraying with β-cyfluthrin solution. Naturally grown alfalfa served as the control. The results show that the incidence and disease index of spring black stem disease in the pathogen treatment and pathogen+aphid treatment groups reached 54.67%-82.67% and 20.93%-40.93%， respectively， significantly higher than those in the control and insecticide-protected groups. Compared with the control and insecticide groups， the pathogen treatment group and pathogen+aphid treatment group showed decreases in alfalfa yield （decreases of 20.87%-22.17%）. Pests and diseases had a greater impact on the nutrient contents and feeding value of alfalfa leaves than on stems or the entire aboveground part， especially in the pathogen+aphid treatment group. Compared with the control， the pathogen treatment group showed significantly reduced calcium and sulfur contents in the leaves and significantly increased potassium content （P<0.05）. The protein content in alfalfa leaves was significantly lower in the pathogen treatment group， aphid treatment group， and pathogen+aphid treatment group than in the insecticide group. The monosaccaride content in leaves was higher in the pathogen+aphid treatment group than in the control （P<0.05）， and the acetic acid and lactic acid contents in alfalfa leaves were lower in the pathogen+aphid treatment group than in the pathogen-only treatment group （P<0.05）. The results of this study provide a theoretical basis for assessing alfalfa crop losses caused by spring black stem disease and pea aphid， and offer theoretical guidance for the development and refinement of pest and disease control strategies.

Advances in research on fungal diseases of Coptis

Hui LYU, Xiao-li WU, Zan YANG, Xiao ZHAO, Tian-run ZHENG, Yu-jia LUO, Xin-yu FU, Da-xia CHEN

2025, 34(12):  206-216.  DOI: 10.11686/cyxb2025038

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Members of the genus Coptis， in the Ranunculaceae family， are perennial herbaceous plants commonly known for their medicinal properties. Fungal diseases are among the main types of plant diseases and they limit the production of Coptis species. The planting area of Coptis in China is approximately 10000 ha. To date， there has been limited research on its fungal diseases. To provide a background for research on the fungal diseases of Coptis in the future， we have summarized the results of domestic and international research， describing the types of diseases and pathogens， their distribution， damage， and occurrence patterns， current control methods， and other relevant problems. As of 2025， 40 diseases caused by 32 fungal species have been identified on 10 Coptis species， distributed across six countries and 10 regions. These include 27 foliar and stem diseases and 13 root diseases. Among them， 15 diseases were reported only abroad， while 25 were reported exclusively in China， with the highest number （16） in Chongqing. Research on the fungal diseases of Coptis abroad is limited. In China， studies have focused mainly on anthracnose， leaf spot， powdery mildew， southern blight， and root rot， and have described occurrence patterns， impacts， and control measures. Research on the pathogenic mechanisms remains insufficient. It is recommended to focus on major diseases affecting Coptis production， clarify pathogen taxonomy， conduct detailed studies on occurrence patterns and pathogenic mechanisms， and evaluate the effects of plant diseases on active medicinal compounds. In addition， it is important to generate new disease-resistant varieties and develop effective disease control strategies to promote sustainable Coptis production.