Table of Content

20 October 2026, Volume 35 Issue 10

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Spatial variation of mineral-associated organic carbon in grassland on the northern slopes of the Tianshan Mountains

Jing SI, Yao WANG, Zhong-lin XU

2026, 35(10):  1-14.  DOI: 10.11686/cyxb2025433

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Mineral-associated organic carbon （MAOC） is a relatively stable and important fraction of soil organic carbon， and variations in its content directly affect the composition and long-term stability of soil carbon pools. In arid grassland ecosystems in particular， MAOC plays a key role in long-term carbon sequestration and the functioning of carbon sinks. However， studies on the spatial pattern of MAOC in grasslands of the arid and semi-arid regions of central Asia and the main factors controling it remain limited. In this study， we focused on grassland on the northern slope of the Tianshan Mountains in Xinjiang， and examined the spatial distribution characteristics and driving mechanisms of MAOC considering grassland type， soil profile， and topographic-climatic-soil factors. The results show that： 1） The MAOC content decreased with increasing soil depth， with the largest decreases in mountain meadow， followed by typical steppe， and then desert steppe； 2） The MAOC content was significantly negatively correlated with air temperature and soil pH， and significantly positively correlated with elevation， slope， available phosphorus and total nitrogen； 3） The carbon stability index values were higher in deeper soil layers， indicative of higher carbon stability in deeper layers； 4） A spatial prediction model for MAOC based on multiple regression analyses revealed a spatially heterogeneous pattern where the MAOC content increased from northwest to southeast. These results deepen our understanding of the spatial characteristics of MAOC and factors influencing MAOC in arid and semi-arid grassland ecosystems， and provide scientific support for formulating land carbon management policies under the “dual carbon” strategy in Xinjiang and other dryland regions.

Effects of summer cover cropping on soil fertility in saline-alkali farmland of the Yellow River Delta

Ding-wen ZHANG, Yang LI, Zhen-kai LI, Shi-de DONG, Han-wen LIU, Chun-xiao YU, Ying WEN, Ying-zi Chen, Guang-mei WANG

2026, 35(10):  15-29.  DOI: 10.11686/cyxb2025401

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Improvement of soil fertility in saline-alkali farmland is a key indicator of the improvement and high-quality development of saline-alkali land. This research investigated the effects of summer cover cropping on soil fertility in saline-alkali farmland of the Yellow River Delta. A field experiment was conducted at the Yellow River Delta Saline-Alkali Agro-ecosystem Observation and Research Station， which is affiliated with the Yantai Institute of Coastal Zone Research， Chinese Academy of Sciences. Two levels of soil salinity were established： light salinity （0.2%） and moderate salinity （0.4%）. Three crop rotation systems were used： sorghum-sudangrass hybrid （Sorghum bicolor×Sorghum sudanense）-winter wheat （Triticum aestivum） （HW）， sesbania （Sesbania cannabina）-winter wheat （SW）， and summer maize （Zea mays）-winter wheat （MW）， resulting in six treatments with three replicates each. The local traditional summer maize-winter wheat rotation was utilized as the control. The present study investigated the effects of soil salinity levels and summer cover crop types on the soil fertility index （SFI） of the subsequent winter wheat crop. It was found that under light salinity， SFI in HW and SW increased by 46.24% and 19.98%， respectively， at sowing stage， and by 8.61% and 7.12%， respectively， at regreening stage， compared with MW. At maturity stage， HW showed an increase of 14.29% compared to MW. Under moderate salinity， SFI in HW at sowing stage was 14.67% higher than that in MW. For a given rotation system， HW exhibited a higher SFI at sowing stage under light than under moderate salinity， whereas MW showed a higher SFI at maturity stage under moderate than under light salinity. SFI was significantly positively correlated with soil available phosphorus， nitrate nitrogen， ammonium nitrogen， total nitrogen， total phosphorus， and total potassium， and significantly negatively correlated with soil salinity. Overall， both the sorghum-sudangrass hybrid-winter wheat and sesbania-winter wheat rotations improved soil fertility in lightly saline farmland and can be considered suitable rotation patterns for the amelioration of saline-alkali land in the Yellow River Delta.

Livelihood capital and herders’ perception of grassland restoration： An empirical analysis based on the Qilian Mountain pastoral area

Jing JIANG, Jin-hua HU, Gong-cheng HUANG, Xin-ling JIANG, Yu-bing FAN, Zeng TANG, Hua QIN

2026, 35(10):  30-47.  DOI: 10.11686/cyxb2025418

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Grassland degradation presents a serious threat to Chinese ecological security and sustainable development. As the direct decision-makers in grassland management， herders’ perception of grassland restoration is crucial to the ecological recovery of degraded grasslands. This study employs the binary Probit model and multi-angle heterogeneity analysis to analyze the impact on herders’ perception of grassland restoration， of various factors under the five dimensions of livelihood capital. The findings indicate that in terms of natural capital， for every additional 666.67 ha of grassland operated by herders， the probability of their having a positive perception of the grassland restoration status decreases by 1.5%. Regarding material capital， for every increase of 100 sheep units in the number of livestock raised by herders， their perception of grassland restoration status declines by 1.4%. With respect to financial capital， for every additional 10000 CNY of ecological compensation and rewards received by herders， their perception of grassland restoration rises by 3.8%. With respect to social capital， for every one-unit increase in the degree of mutual influence among herders， their perception of grassland restoration increases by 2.0%. Furthermore， for every one-unit increase in herders’ environmental awareness， their perception of grassland restoration increases by 3.2%. There are differences in herders’ perception of grassland restoration between the northern and southern slopes of the Qilian Mountains， the effect of the ecological compensation policy is more significant in the northern slope area， while the number of laborers and environmental awareness of herders in the southern slope area have a more positive effect on their perception of grassland restoration. The design of relevant policies should take into account the role and the different influences of various dimensions of livelihood capital on herders’ perception of grassland restoration.

Effects of nitrogen addition on the productivity of the Medicago sativa ‘Gannong No.9’-LL2 Rhizobium symbiotic system

Bing-sen ZHAO, Wen-juan KANG, Shang-li SHI, Jian GUAN, Bao-fu LU, Yi-lin HAN, Jing-jing WANG, Feng-jiao CHEN

2026, 35(10):  48-60.  DOI: 10.11686/cyxb2025425

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The “Gannong No. 9 alfalfa（Medicago sativa）-Rhizobium strain LL2” symbiotic system is recognized as an efficient nitrogen-fixing association. To clarify the effects of nitrogen application rates on the productivity of this system， four nitrogen （N） addition treatments were established： 0 kg·ha^-1 （R）， 35.09 kg·ha^-1 （NR₁）， 46.79 kg·ha?¹ （NR₂）， and 58.48 kg·ha^-1 （NR₃）. Corresponding non-inoculated controls at each nitrogen level were included： 0 kg·ha^-1 （CK₁）， 35.09 kg·ha^-1 （CK₂）， 46.79 kg·ha^-1 （CK₃）， and 58.48 kg·ha^-1 （CK₄）. Measurements were conducted at the branching， budding， and early flowering stages. These included the number of effective nodules per plant， effective nodule weight per plant， nitrogenase activity， plant height， root length， aboveground and belowground dry weight， crude protein （CP）， ether extract （EE）， neutral detergent fiber （NDF）， acid detergent fiber （ADF）， and forage grading index （FGI）. This study evaluated the effects of nitrogen addition on nodulation and nitrogen fixation， plant growth， and forage quality in the Gannong No.9-LL2 symbiotic system. The results showed that in the NR₂ treatment， the number of effective nodules per plant in the Gannong 9-LL2 symbiotic system was 22， 32， and 35 at the branching， budding， and initial flowering stages， respectively. Effective nodule weight per plant was 0.0353， 0.0745， and 0.1013 g·plant^-1， and nitrogenase activity was 4.79， 26.51， and 28.13 μmol·g^-1·h^-1 at the same development stages， displaying an increasing trend as growth progressed. At the early flowering stage， the plant height was 51.92 cm and CP content was 20.42%. Root length and both aboveground and belowground dry weight were significantly higher than those of other nitrogen treatments and the controls （P<0.05）. Meanwhile， NDF and ADF contents were significantly lower than those under other nitrogen addition treatments and the control （P<0.05）. The strong nodulation and nitrogen-fixing responses and the growth-promoting effect of NR₂ occurred mainly at the branching stage， where the number of effective nodules per plant was 84.44% higher than that of the R treatment， and nodule weight per plant and nitrogenase activity were 2.5-fold and 3.1-fold higher than those of R treatment， respectively. Increases in root length， aboveground dry weight， and belowground dry weight were also greater at the branching stage than at the budding and early flowering stages. At the budding stage， fiber fractions were reduced in NR₂， with NDF and ADF contents reduced by 3.82% and 6.03%， respectively， compared with R treatment， and this effect was strongest than at the branching and early flowering stages. At the early flowering stage， crude protein was markedly enhanced in NR₂ where CP content was increased by 9.04% relative to R treatment. Similar， but smaller effects were observed at earlier growth stages. During grading at the early flowering stage， the FGI value of NR₂ was 54.91 MJ·d^-1， corresponding to a premium forage grade. To summarize， the NR₂ nitrogen application rate of 46.79 kg·ha^-1 was identified as the optimal N level for maximizing the productivity of the Gannong No.9-LL2 symbiotic system. These findings provide research data useful for development of cultivation practices aimed at improving the productivity of the Gannong No.9 alfalfa-LL2 symbiotic system.

Optimization of alfalfa pasture planting patterns and nitrogen fertilizer management to reduce greenhouse gas emissions

Min-hua YIN, Wen-jing CHANG, Jian-xin YIN, Ya-ya DUAN, Hai-yan LI, Yan-biao WANG, Yan-xia KANG, Yan-lin MA, Ya-yu WANG, Guang-ping QI

2026, 35(10):  61-78.  DOI: 10.11686/cyxb2025443

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Agricultural production is a significant contributor to global greenhouse gas emissions. Alfalfa （Medicago sativa） is the world’s most widely cultivated forage crop， and it fixes nitrogen via its root nodules. However， in intensive production systems targeting high yields and quality， this crop is often supplied with nitrogen fertilizers， and this impacts greenhouse gas emissions. Optimizing planting management practices is an effective approach to mitigate greenhouse gas emissions from alfalfa fields. In this study， we analyzed the effects of planting patterns and nitrogen management on CO₂， CH₄， and N₂O emissions from alfalfa fields. We conducted a field experiment to analyze the effects on greenhouse gas emissions of three planting patterns （flat planting， FP； ridge-furrow planting with biodegradable film mulching over the ridge， BM； ridge-furrow planting with plastic film mulching over the ridge， PM）， two types of nitrogen fertilizer （urea， U； controlled-release nitrogen fertilizer， C）， and four nitrogen application levels （0， 80， 160， 240 kg·ha^-1）. The results show that alfalfa fields served as a net source of CO₂ and N₂O emissions and a sink for CH₄ absorption. Compared with application of urea， application of controlled-release nitrogen fertilizer significantly reduced cumulative CO₂ and N₂O emissions while increasing cumulative CH₄ uptake. Cumulative CO₂ emissions， N₂O emissions， and CH₄ uptake all increased with increasing nitrogen application levels， with the largest increases in the PM treatment， followed by the BM treatment， and then the FP treatment. Alfalfa yields in the BM and PM treatments were 43.56% and 30.07% higher， respectively， than that in the FP treatment. Alfalfa yields were 8.46% higher in the controlled-release nitrogen fertilizer treatments than in the urea treatments. The highest yield （24.83 t·ha^-1） was in the treatment combining 160 kg·ha^-1 controlled-release nitrogen fertilizer and biodegradable mulch film on ridges， representing a 97.11% increase compared with the yield in the unmulched， nitrogen-free treatment. The global warming potential （GWP） and greenhouse gas emission intensity （GHGI） were 12.26% and 15.04%， lower， respectively， in the controlled-release nitrogen fertilizer treatment than in the urea treatment. The GWP in the BM treatment was 15.28% lower than that in the PM treatment， and 15.12% higher than that in the FP treatment. The lowest GHGI was in the BM treatment， and was 11.84% lower than that in the PM treatment and 17.18% lower than that in the FP treatment. In summary， under these conditions， application of 160 kg·ha^-1 controlled-release nitrogen fertilizer combined with ridge-covered biodegradable mulch （BMC₂ treatment） is the recommended cropping management system for increasing alfalfa yields and reducing greenhouse gas emissions in the Gansu Yellow River irrigation district and similar ecological zones.

A study of the point occurrence pattern of Artemisia ordosica populations and their spatial correlation with Caragana microphylla occurrence in the Mu Us sandy land

Rui ZHANG, Tie-juan WANG, Bing-bing ZHANG, Jing FENG, Jin-ling SHAO

2026, 35(10):  79-90.  DOI: 10.11686/cyxb2025422

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Artemisia ordosica， is a valuable sand-fixing plant in China and is also important as a dominant species in the sand plant community. This research investigated the population distribution pattern of A. ordosica during the process of sand fixation and the dynamics of population change， as well as the relationship with the sand-fixing plant Caragana microphylla， in order to understand the mechanisms of population dynamics and the factors influencing the distribution pattern. In this study， A. ordosica communities coexisting with C. microphylla were selected from semi-fixed and fixed sandy land in within the Mu Us sandy land. Based on the complete spatial randomness model （CSR）， heterogeneous poisson model （HP）， antecedent condition model （AC） and toroidal shift model （TS） of point pattern， the spatial distribution pattern of A. ordosica populations， the spatial correlation of three size classes （Ⅰ， d≤25 cm；Ⅱ， 25 cm<d≤75 cm；Ⅲ， d>75 cm） and the interaction with C. microphylla were studied at a scale of 20 m. It was found that the age structure of A. ordosica populations was a ‘growth’ type in semi-fixed sandy land while the population exhibited a transition stage from stability to decline in fixed sandy land. According to the CSR model， both the A. ordosica populations （including all three size classes） and the C. microphylla populations exhibited an aggregated distribution at small scales or small to medium scales， and the degree of aggregation increased with the degree of sand fixation. The results of the HP model after eliminating habitat heterogeneity showed that the aggregation decreased to varying degrees， and the semi-fixed sand population was more obvious. According to the AC model， there were different degrees of positive correlations between class I and Ⅱ， and class Ⅱ and Ⅲ individuals of A. ordosica， and the positive correlation was stronger in fixed sandy land， while class Ⅰ and class Ⅲ plants showed no correlation in both types of sandy land. With increasing scale， especially at scales greater than 16 m， A. ordosica and C. microphylla mostly showed random distribution and uniform distribution （HP model）， and A. ordosica mostly showed no correlation between different size classes， reflecting a decrease in interaction between individuals. With the fixation of sandy land， the number of individuals and density of the two plant species increased significantly. The results of the TS model showed that the interspecific association showed a negative correlation from the small scale （0-1.0 m） of the semi-fixed sandy land to the small and medium scale （0-7.8 m） of the fixed sandy land， indicating that the competition between A. ordosica and C. microphylla was significantly enhanced. The research results provide reference data for the selection of species and the combination of planting methods in sandy land management.

An evaluation using multivariate statistical methods of suitability of 30 Chinese milk vetch germplasm lines for dual purpose vegetable and green manure use

Cai-ling LIU, Shui-zhen HUANG, Yi-bin HUANG, Hong-yun YE, Chun-mei HE, Shao-jie ZHONG, Qing-hua LI, Fei WANG

2026, 35(10):  91-105.  DOI: 10.11686/cyxb2025363

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Chinese milk vetch （Astragalus sinicus） is used both as a green manure fertilizer and a vegetable crop. Hence， we evaluated 30 representative Chinese milk vetch germplasm lines with different maturity dates and from different regions of China， to identify those best suited from an economic benefit perspective for dual purpose green manure and vegetable use. Harvests to determine nutrient status for green manure use and vegetable-use traits were carried out at the budding and post-cutting regrowth crop development stages. Data analysis involved integration of principal component analysis， membership function and cluster analysis. It was found that， with respect to vegetable-use quality traits， early-maturing varieties had higher contents of calcium， manganese， dietary fiber and protein. Medium-maturing varieties exhibited higher contents of zinc， selenium， soluble sugar and vitamin C. Late maturing varieties displayed higher levels of manganese， iron， copper and fresh herbage yield. The coefficients of variation for iron， selenium， vitamin C and fresh herbage yield all exceeded 20%. For fertilizer-use quality traits， early-maturing varieties exhibited the highest concentration for all of the measured nutrients， as well as for hay yield， while the coefficients of variation for nitrogen， phosphorus， potassium， organic matter and hay yield all exceeded 25%. Concerning suitability for vegetable use of germplasm lines of different origins， germplasm resources from northwest areas had higher contents of magnesium， iron， manganese， copper and dietary fiber； those from south China exhibited higher contents of calcium， soluble sugar； those from central China had higher zinc， vitamin C and protein， while those from east China had higher selenium content. The fresh herbage yield of accessions from the southwest area was relatively high. For nutrients of interest for fertilizer-use， germplasm resources from east China had higher phosphorus accumulation； those from south China exhibited higher accumulations of nitrogen， phosphorus， organic matter accumulation and hay yield. Cluster analysis based on a D value from multivariate data analysis classified the tested germplasm into five clusters （high-quality， excellent， medium， poor and low-grade）. ‘Minzi No.1’ was a high-quality dual-purpose vegetable and green manure variety； ‘Xiangxiang’， ‘Jinsha’ and ‘Xinyangzi’ were excellent dual-purpose vegetable and green manure varieties. Six varieties including ‘Pucheng No.2’， ‘Xiangzi No.1’ and ‘Yijiangzi No.3’ were medium-quality dual-purpose vegetable and green manure varieties. In summary， ‘Minzi No.1’ and several other accessions were found to be suitable for two-stage utilization as vegetable and green manure.

Screening of cadmium-resistant bacteria and its effect on the growth and cadmium accumulation of Pharbitis nil seedlings

Juan SONG, Gen ZHAO, Jing-han WANG, Wei GU, Jin-kai LIN, Dong-rui HONG, Li-qin ZHANG, Li-jing MIN

2026, 35(10):  106-116.  DOI: 10.11686/cyxb2025415

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This study investigated the biological characteristics of Cd-resistant microorganisms and their effects on plant cadmium tolerance， providing scientific evidence for the joint microbial-plant remediation of heavy metal-polluted soils. Cd-resistant bacteria strains were isolated from polluted soil and identified using morphological， physiological， biochemical， and 16S rDNA sequence analysis. The liquid culture method was used to assess the strain’s tolerance to Cd and other heavy metals （Fe， Cu， Pb）. Fourier transform infrared （FTIR） technology was applied for characterization. The effect of the strain Hz_Cp in conjunction with Pharbitis nil on cadmium accumulation was analyzed through petri dish experiments. RT-qPCR was used to detect the expression of genes related to cadmium tolerance in P. nil. The isolated strain Hz_Cp was identified as a species of Cupriavidus， with a cadmium tolerance concentration of up to 1600 mg·L^-1. When cultured at pH 7.0 conditions， the strain removed 90.16% of cadmium. In addition to its ability to fix nitrogen， secrete indole-3-acetic acid （IAA）， and produce siderophores， this strain also displays remarkable tolerance to a range of abiotic stresses， including heavy metals， salt， and extreme temperatures. Cupriavidus sp. （Hz_Cp） bio-adsorbs cadmium ions through functional groups such as -OH， -COOH， and -PO₄^3-. P. nil was able to remove 25.34% of cadmium ions from the culture medium （reducing from 200.00 to 149.32 mg·L^-1）， and the addition of Hz_Cp significantly enhanced its cadmium tolerance. The Cupriavidus strain Hz_Cp not only significantly increased the chlorophyll， carotenoid， and anthocyanin content in P. nil but also improved peroxidase （POD） and superoxide dismutase （SOD） activities， and upregulated the expression of genes such as IpYUC1 and IpPAP1. Hz_Cp promotes the growth of P. nil seedlings under cadmium stress while reducing cadmium accumulation， demonstrating its potential for application in remediation of soil heavy metal pollution.

The effects of biochar on the physiological responses and gene expression of Bromus inermis seedlings under saline-alkaline stress

Rui GAN, Guo-bin YANG, Xiao-qing SUI, Jing QI, Gui-li JIN, Yu-xiang WANG, Jian PENG

2026, 35(10):  117-128.  DOI: 10.11686/cyxb2025372

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Biochar is widely recognized for its ability to improve the properties and microstructure of saline-alkaline soils， thereby promoting plant growth. This study investigated biochar mitigating effects on Bromus inermis seedlings under saline-alkaline stress， and was conducted using B. inermis cultivar ‘Xinque No.3’in sulfate-type saline soil in Xinjiang， with five biochar application rates ［0， 30， 50， 70， and 90 t·ha^-1； control （T₀）， T₁-T₄， respectively］. The changes in seedling growth indicators， photosynthetic characteristics， physiological responses， and expression levels of salt-alkaline tolerance-related genes were analyzed. It was found that the optimal mitigating effect was achieved with 70 t·ha^-1 biochar （T₃）： compared with the control. In T₃， compared to the control， plant height， total biomass， root total length， and root surface area were increased （P<0.05） by 41.85%， 34.38%， 46.94%， and 63.98%， respectively. Net photosynthetic rate and chlorophyll （a+b） content were increased by 32.06% and 118.44%， respectively， with stable leaf anatomical structure， increased stomatal density， and intact vascular bundle development. The accumulation of hydrogen peroxide and malondialdehyde was decreased significantly， accompanied by a synchronous reduction in antioxidant enzyme activity. At the molecular level， the expression levels of salt-alkaline tolerance-related genes such as BiBHLH， BiAP2/ERF， BiLRR， and BiABCC1 were significantly downregulated. In conclusion， in this experiment the application of 70 t·ha^-1 of biochar effectively alleviated the inhibitory effect of saline-alkaline stress on the growth of B. inermis seedlings， enhanced their growth performance and adaptability in saline-alkaline environments. This experiment provides research data to support the ecological utilization of B. inermis in localities with saline-alkaline soil.

Methods for breaking seed dormancy in Jerusalem artichoke

Ming-xu DAI, Guo-yin ZHANG, Zheng-jiang WU, Yi-hao DING, Lei ZHU, Zhen YANG, Su-lyu MENG, Zi-han HE, Hui-xia LIU

2026, 35(10):  129-143.  DOI: 10.11686/cyxb2025515

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The aim of this work was to investigate methods for breaking seed dormancy in Jerusalem artichoke （Helianthus tuberosus）. Seeds of Jerusalem artichoke were left intact or dehulled， and then germinated at 25 ℃ on paper after imbibing for various lengths of time （1， 2， 3， 4， or 5 h） in solutions containing different concentrations （0， 100， 200， 300 mg·L?1） of ethephon （ETH）， indole-3-acetic acid （IAA）， α-naphthylacetic acid （NAA）， or gibberellin （GA₃）. The overall goal was to identify the optimal conditions for breaking seed dormancy. Seed dehulling was found to be crucial for breaking dormancy. Treatment with both IAA and NAA inhibited seed germination， whereas treatment with GA? had no effect on intact seeds. Dehulled seeds exhibited a dose-dependent response to GA₃ in terms of germination percentage， which initially increased and then decreased as the GA₃ concentration increased. The peak germination percentage （43%） was achieved by imbibing dehulled seeds in GA₃ at 200 mg·L^-1， but this percentage was too low for production. Imbibing in ETH （100-300 mg·L^-1） promoted germination of both intact and dehulled seeds， with the latter showing final germination percentages of 56.67% to 63.33%. The root length of Jerusalem artichoke seedlings also showed a dose-response relationship with ETH， increasing initially and then decreasing as the ETH concentration increased. The method of dehulling seeds combined with imbibing in an ETH solution was further optimized to break seed dormancy. Imbibing dehulled seeds in ETH advanced the initial germination time by 1 day and significantly increased all germination indexes （P<0.05）. The ETH concentration had a significant effect on the germination index of dehulled Jerusalem artichoke seeds， with the index gradually increasing as the ETH concentration increased. The imbibition time had a greater impact on germination potential， which initially increased and then decreased with prolonged imbibition time. The optimal treatment was imbibing dehulled seeds in ETH at 100-200 mg·L^-1 for 3-4 hours； this yielded a cumulative germination potential of >70% and a germination rate of >78%. Among all treatments， imbibing dehulled seeds in ETH at 100 mg·L?1 for 3 hours yielded the highest final germination rate of 81.67%. The optimal imbibition time in terms of root and shoot lengths was 3-4 h， although imbibition time did not affect bud length. The results indicate that seed dormancy in Jerusalem artichoke is controlled physically by the seed coat and physiologically by the balance of growth regulators in the seed coat and the seeds themselves. Under these conditions， the optimal treatment for breaking the seed dormancy of Jerusalem artichoke was dehulling combined with imbibing in ETH solution （100-200 mg·L?1） for 3-4 hours.

A functional study of the role of SgNAC1 in salt tolerance in Stylosanthes

Yi-hua WANG, Ci REN, Pan-yu ZHANG, Cui-ling LIU, Liang-liang HE, Jie-yi LI, Chao LIU, Shu CHEN

2026, 35(10):  144-155.  DOI: 10.11686/cyxb2025436

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Stylosanthes （stylo） is an economically important leguminous forage crop in tropical and subtropical regions. It plays critical roles in forage production， soil and water conservation， and orchard ground cover. Because its role is similar to that of alfalfa （Medicago sativa）， stylo is often referred to as ‘tropical alfalfa’. With the continuing global expansion of saline-alkali land areas， salt stress reduces the growth and yield of stylo， and has become a key constraint on its cultivation and promotion. Therefore， it is urgent to identify key genes related to salt tolerance and clarify their functions. The NAC family of transcription factors is known to regulate salt tolerance， but the specific role of SgNAC1 in the salt tolerance of stylo remains unclear. In this study， we analyzed the transcript profiles of SgNAC1 in leaves and stems of the Stylosanthesguianensis line ‘YN02’ using quantitative real-time PCR. The results show that under salt stress （150 mmol·L^-1 NaCl）， the transcript abundance of SgNAC1 in leaves decreased to the lowest level at 2 hours after treatment （HAT）， but peaked in stems at 6 HAT. After treatment with abscisic acid （ABA）， the transcript abundance of SgNAC1 in both leaves and stems peaked at 1 HAT. In the combined ABA+NaCl treatment， the transcript abundance of SgNAC1 in leaves peaked at 0.5 HAT， whereas in stems， it exhibited two peaks at 1 HAT and 12 HAT. Thus， SgNAC1 in stems responded to salt stress at approximately 12 HAT， and to both ABA and ABA+NaCl at approximately 1 HAT. Under salt stress， the transcript abundance of SgNAC1 in leaves decreased significantly at 2 HAT， implying that it may be regulated by other factors. The dual expression peaks of SgNAC1 in stems after treatment with ABA+NaCl may indicate a synergistic effect of NaCl and ABA. Transgenic tobacco （Nicotiana tabacum） lines overexpressing SgNAC1 （SgNAC1-OE） were obtained by transforming wild-type tobacco via the Agrobacterium tumefaciens-mediated leaf disc method. When both wild-type and SgNAC1-OE tobacco plants were subjected to salt stress （300 mmol·L^-1 NaCl）， the SgNAC1-OE tobacco plants showed significantly increased proline levels and salt tolerance， compared with the wild-type plants. The results of this study reveal the transcript profiles of SgNAC1 in different tissues of stylo， and the experiments with transgenic tobacco lines overexpressing SgNAC1 confirm its ability to increase salt tolerance. Together， our results provide a theoretical basis for further research on salt tolerance mechanisms， and identify a genetic resource for breeding salt-tolerant stylo.

Optimization of an embryonic callus induction and subculture system for Zoysia japonica cv. ‘Zenith’

Ci REN, Yi-hua WANG, Long-long MA, Cui-ling LIU, Jie-yi LI, Chao LIU, Liang-liang HE, Shu CHEN

2026, 35(10):  156-166.  DOI: 10.11686/cyxb2025434

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There are several technical bottlenecks in Zoysia japonica tissue culture， including the low induction rate of embryogenic callus and severe browning during subculture. This study aimed to address these problems to establish an efficient and stable plant regeneration system for Z. japonica. Mature seeds of the seed-propagated cultivar ‘Zenith’ were used as explants. These explants were cultured on basal induction medium （IM） consisting of Murashige & Skoog medium supplemented with 2 mg·L^-1 2，4-dichlorophenoxyacetic acid and 0.2 mg·L^-1 6-benzylaminopurine. Key regulatory factors were screened through three successive rounds of single-factor experiments. The first round of screening revealed a promoting effect of 5 mg·L^-1 vitamin B1 and 25 mg·L^-1 α-ketoglutaric acid on embryogenic callus induction， although the maximum embryogenic callus induction rate was only 6.74%. The second round of screening identified dicamba （2 mg·L^-1） as a core hormonal regulator that significantly increased the embryogenic callus induction rate to 19.65%. In the third round of screening， the addition of 25 mg·L^-1 α-ketoglutaric acid to IM+2 mg·L^-1 dicamba further increased the embryogenic callus induction efficiency by 62.38%. The addition of 0.05 mg·L^-1 abscisic acid to the medium effectively inhibited premature differentiation of callus during subculturing. Browning was significantly suppressed by the addition of 4 g·L^-1 polyvinylpyrrolidone （PVP）， 0.5-1.0 g·L^-1 activated carbon， or 0.001-0.005 g·L^-1 silver nitrate， with PVP demonstrating the strongest inhibitory effect. In summary， a complete， efficient regeneration system was established for Z. japonica. This system provides a reliable source of recipient materials for molecular breeding applications such as gene editing and genetic transformation. The findings of this study provide a valuable theoretical and technical reference for developing regeneration systems for other warm-season turf grasses.

Effects of biogas slurry addition on nitrogen， phosphorus， and potassium stoichiometry and feed quality of Pennisetum purpureum

Xiao-yun HUANG, Zheng-xiang LIANG, Zhi-feng WU, Liu-ting ZHOU, Chang-fu CHEN, Jia-li LIN, Tao LUO, Xiu-sheng HUANG

2026, 35(10):  167-179.  DOI: 10.11686/cyxb2025427

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In this study， we investigated the effects of adding biogas slurry on the nutrient and feed quality of Pennisetum purpureum. Biogas slurry was applied to P. purpureum at five different rates （0， 50， 100， 150 and 200 kg N·ha^-1 per application， denoted as CK， N₅₀， N₁₀₀， N₁₅₀ and N₂₀₀， respectively） three times during a 45-day cutting cycle. The contents of nitrogen （N）， phosphorus （P）， potassium （K）， crude protein （CP）， neutral detergent fiber （NDF）， and acid detergent fiber （ADF） in stems and leaves were measured， and the effects of biogas slurry addition on CP， relative feeding value （RFV）， and the N， P and K stoichiometry of P. purpureum were analyzed. The results show that the addition of biogas slurry significantly increased the CP and N contents of P. purpureum stems （P<0.05）， and there were significant differences in responses among different cutting periods and different organs （P<0.001）. The N₅₀ treatment led to a significant reduction in the ADF content in the leaves at the second cutting （P<0.05） and significant differences in ADF contents among different organs （P<0.001）. At the second cutting， the RFV of leaves was highest in the N₁₀₀ treatment， and was significantly higher than that in the N₂₀₀ treatment （P<0.05）. There was a significant positive correlation between CP and RFV. Both CP and RFV were significantly positively correlated with N， K， N∶P and K∶P in stems and N and P in leaves， and negatively correlated with NDF and ADF in both organs （P<0.05）. A stepwise regression analysis and structural equation model showed that the N contents of stems and leaves significantly and positively affected the CP content of P. purpureum （P<0.001）， with total effect values of 0.92 and 0.32， respectively. The stem P content and leaf K∶P and P content jointly affected RFV， with total effect values of -0.86， 0.59， and 0.57， respectively. In conclusion， application of biogas slurry affected the N and P contents of stems and leaves and the K∶P of leaves， thereby directly or indirectly regulating the feed quality of P. purpureum.

Effects of salicylic acid and complex chitin on the growth and nutritional quality of spearmint

Xin-ying LIU, Jing-jing JIAN, Wan-lu ZHAO, Can CUI, Fan YANG, Jun-xin YAN, Mu HE

2026, 35(10):  180-191.  DOI: 10.11686/cyxb2025426

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In this study， we investigated the effects of salicylic acid and complex chitin as single and combined treatments on the growth and nutritional quality of spearmint （Mentha spicata）. The experiment consisted of a control and four treatments： Ethanol， 300 mg·L^-1 salicylic acid， 0.4% w/v complex chitin， and the combined treatment （300 mg·L^-1 salicylic acid + 0.4% complex chitin）. At 60 days after treatment， plant growth， photosynthetic characteristics， and nutritional quality indexes were determined. The results show that， compared with the control plants， the plants treated with salicylic acid and complex chitin showed significantly increased growth and nutritional quality. The combined treatment had the most significant effect， resulting in significantly increased biomass， root system indexes， and photosynthetic parameters； increased absorption efficiency of nitrogen， phosphorus， and potassium； and increased contents of basic nutritional components （total sugars， crude protein， crude fat， and crude fiber） and antioxidant substances （total phenols， total flavonoids， and ascorbic acid）. Specifically， the contents of total sugars， crude protein， crude fat， and crude fiber were 56.78%， 26.77%， 26.58%， and 38.24% higher， respectively， in the combined treatment compared with the control. A membership function analysis of multiple traits ranked the treatments， from highest nutritional quality of spearmint plants to lowest， as follows： combined treatment > complex chitin treatment > salicylic acid treatment > control > ethanol treatment. The results of this study provide a reference for synergistically improving the nutritional quality of spearmint using salicylic acid and complex chitin.

Effects of molybdenum， silicon， and boron addition on the photosynthetic physiology of Elymus breviaristatus and a multivariate evaluation of growth performance

Zu-yan MA, Shi-kui DONG, Yin LI, Ran ZHANG, Dan-jia TU, Gui-ling WU, Jian-jun SHI, De-jun SHI

2026, 35(10):  192-206.  DOI: 10.11686/cyxb2025438

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The harsh environment of the Qinghai-Xizang Plateau， characterized by high elevation， low temperature， drought， and intense ultraviolet radiation， severely limits forage grass growth. Elymus breviaristatus is a high-quality forage species widely used for restoration of degraded grasslands. However， this forage species has shown yield declines during ongoing grassland restoration， and conventional fertilization is insufficient to meet its growth requirements. Instead， trace-element supplementation may be critical for sustaining stable and high yields. To explore the effects of trace element supplementation on this important forage grass， a pot experiment was conducted in which E. breviaristatus was treated with molybdenum ［（NH?）?MoO?： 0.15， 0.30， and 0.45 g·L^-1］， silicon （SiO?NPs： 0.10， 0.20， and 0.40 g·L^-1）， or boron （H?BO?： 0.15， 0.30， and 0.45 g·L^-1） applied as foliar sprays. The results show that all three elements significantly increased plant height and aboveground dry weight （P<0.05）， compared with the control. Specifically， plant height was increased by 34.56% in the 0.30 g·L^-1 molybdenum treatment and root length was increased by 59.86% in the 0.3 g·L^-1 molybdenum treatment and by 79.53% in the 0.1 g·L^-1 silicon treatment. Molybdenum and silicon addition significantly enhanced photosynthetic capacity. The net photosynthetic rate was increased by 111.53% in the 0.4 g·L^-1 silicon treatment； and chlorophyll a and b contents were increased by 46.00% and 54.32%， respectively， in the 0.3 g·L?1 molybdenum treatment. Treatment with boron inhibited chlorophyll a accumulation. Antioxidant enzyme activity and osmolyte accumulation were increased in the 0.3 g·L^-1 molybdenum treatment， with peroxidase activity increased by 231.10% and the soluble sugars content increased by 201.48%. The regulatory effects of silicon and boron on enzyme activity and carbohydrate accumulation were concentration dependent. In a principal component analysis （PCA）， the first four components explained 77.66% of the total variance. On the basis of the PCA and a membership function analysis， 0.45 g·L^-1 molybdenum （multivariate analysis D=0.701） was identified as the optimal treatment to improve overall stress resistance. This treatment improved carbon assimilation efficiency by promoting root development， photosynthetic performance， and antioxidant capacity. The results of this study show that molybdenum is a key element for regulating the stress tolerance of an alpine forage grass， and provide a theoretical basis for the targeted restoration of degraded grasslands.

Effects of alfalfa/maize intercropping ratio on crop yield and quality， and water and nitrogen use in the semi-arid area of Longzhong

Pei WU, Cong-ze JIANG, Kai-quan WEI, Rui-bin TIAN, Hui-ting LI, Xian-long YANG, Yong-li LU

2026, 35(10):  207-221.  DOI: 10.11686/cyxb2025419

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This research aimed to determine the optimal intercropping row ratio of alfalfa （Medicago sativa） and maize （Zea mays） in the semi-arid area of the Loess Plateau in central Gansu. The experiment design was based on the traditional monoculture of alfalfa （A） and monoculture of maize （M）. Six intercropping configurations were set up： namely alfalfa/maize intercropping at ratios of 5∶2 （5A2M）， 5∶3 （5A3M）， 7∶2 （7A2M）， 7∶3 （7A3M）， 9∶2 （9A2M） and 9∶3 （9A3M）. The effects of the different intercropping row ratios on the dry matter yield， forage quality and utilization of water and nitrogen resources in the system were analyzed. It was found that： the dry matter yield of the system was highest in the 9A2M treatment （12.7 t·ha^-1）. This was 51.2% higher than the yield of M （8.4 t·ha^-1）. The crude protein yield of the system was highest （3.5 t·ha^-1） in the 9A2M treatment. In terms of nutritional quality， the treatment with the highest maize whole-plant crude protein content （9.0%） was 9A3M， and the intercropping row ratio had no significant effect on the acid and neutral detergent fiber contents of alfalfa. The highest water use efficiency of dry matter production was found in the 9A2M treatment （38.5 kg·ha^-1·mm^-1）. This was a 91.5% and 67.4% increase （P<0.05） compared to the M and A treatments， respectively. In terms of nitrogen fertilizer utilization， the partial factor productivity of nitrogen fertilizer in the 9A2M treatment （149.3 kg·kg^-1） was also the highest among the tested intercropping configurations， and was an increase of 55.0%， 61.2%， 39.8% and 29.7%， respectively， compared with the 5A2M， 5A3M， 7A3M and 9A3M treatments. A multi-trait analysis using a radar chart showed that the 9A2M treatment had the best overall performance and can be recommended for adoption in the semi-arid area of central Gansu.

Progress in research on methods for estimating carbon stock in grassland ecosystems and factors influencing it

Jie LI, Xue-ting YU, Shu-ke ZHAO, Qiu-ga YIXI, Dong-zhou GAMA, Hao WU, Yu-lin SHAN, He-ying YU

2026, 35(10):  222-236.  DOI: 10.11686/cyxb2025429

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Grassland ecosystems constitute a vital component of the global terrestrial carbon pool， and fluctuations in their carbon stocks significantly impact climate change and ecological balance. In this review， we outline the primary methods for estimating grassland carbon stocks and discuss the effects of natural factors and human activities on grassland carbon stocks， on the basis of a bibliometric analysis of research on grassland carbon stocks over the last three decades in the China National Knowledge Infrastructure （CNKI） database. The main points covered in this review are as follows： Grassland carbon stock estimation methods primarily encompass traditional approaches based on field measurements and emerging methods utilizing multi-source data analysis. The use of different grassland classification systems significantly influences grassland area statistics and carbon density values per unit area. Alpine grassland and temperate grasslands constitute China’s predominant grassland types， collectively accounting for over 85% of the nation’s grassland ecosystem carbon stocks. Estimates of carbon stocks for the same grassland type differ depending on the methodologies applied. Climate conditions， topographic features， land-use practices， and anthropogenic disturbances collectively influence grassland ecosystem carbon stock dynamics by regulating vegetation productivity and soil-carbon stability.

Research progress on the effects of Epichloë endophytes on the structure and diversity of microbial communities in host grasses

Mei-jun WANG, Long-xuan CUI, Zhi-biao NAN, Chao XIA

2026, 35(10):  237-251.  DOI: 10.11686/cyxb2025402

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Epichlo? endophytes primarily colonize the aboveground tissues of host grasses， forming a stable， non-pathogenic symbiotic system. These endophytes not only enhance the host’s resistance to biotic and abiotic stresses but also shape the structure and function of rhizosphere， phyllosphere， and seed-associated microbial communities by regulating host physiological metabolism and interacting with diverse microbial populations. This review summarizes recent research on the effects of Epichlo? endophytes on the composition and diversity of microbial communities in the rhizosphere （and soil）， phyllosphere， and seeds of grasses. Present studies demonstrate that Epichlo? endophytes can selectively promote or inhibit the colonization of specific microbial groups in different plant compartments by improving host water-use efficiency， modulating root exudates， altering foliar secondary metabolites， and modifying soil physicochemical properties， while generally reducing pathogen abundance and mycorrhizal infection rates. This review further elaborates on the vertical transmission of these regulatory effects across plant generations and their potential mechanisms in enhancing host adaptation to environmental stresses. In conclusion， this review highlights the pivotal roles of Epichlo? endophytes in regulating grass-associated microbial communities and maintaining ecological functions， and summarizes their established and potential applications in stress-resilient breeding， microbial resource development， and sustainable grassland management.