[Objective]Zn(Zinc)deficiency triggers'hidden hunger'.Enhancing Zn concentration in wheat grains and Zn fertilizer use efficiency through biofortification can effectively increase dietary Zn intake,thereby improving human Zn nutritional status.[Method]The study subjects were two distinctive colored-grain wheat varieties:'Taihei 5'(purple-grained)and'Tailan 8'(blue-grained).A two-year field experiment was conducted from 2022-2024 in Taigu District,Jinzhong City,Shanxi Province.Foliar Zn application was performed at 3-5 days after the flowering of colored-grain wheat(Over 50%of spikes in the wheat field had lemma and palea separation at middle-upper florets while anthers were dehiscing).Five Zn concentration treatments were applied:Zn0(deionized water),Zn1(Zn concentration:440 mg·L-1),Zn2(Zn concentration:587 mg·L-1),Zn3(Zn concentration:733 mg·L-1),Zn4(Zn concentration:880 mg·L-1).Through analysis of grain yield and Zn concentrations in grains,leaves,and stems across multiple post-anthesis periods for both colored-grain wheat types,Zn concentration variation dynamics,Zn accumulation and partitioning characteristics,Zn utilization efficiency,grain Zn biofortification index and grain Zn harvest indices were quantitatively analyzed to evaluate their Zn biofortification efficacy.[Result]Foliar Zn application significantly increased Zn concentrations in all organs and grain yield of colored-grain wheat,The Zn3 treatment produced the highest grain Zn concentration(21.79-67.90 mg·kg-1)and peak grain yield(4 937.36-5 097.27 kg·hm-2).Grain Zn accumulation reached its optimum(251.30-301.54 g·hm-2)under the Zn3 treatment,while Zn concentrations and accumulation in leaves and stems increased linearly with rising application concentrations.With increasing Zn application concentrations,the grain Zn accumulation proportion showed a declining trend(10%-18%),while the leaf Zn accumulation proportion rose to 66%,and stem Zn accumulation remained at 23%-30%.Furthermore efficient synergy in Zn utilization efficiency across all organs of colored-grain wheat was achieved under Zn3 treatment(5.68%-7.70%).With increasing Zn application concentrations,the grain Zn biofortification index and Zn harvest index declined.Compared with Zn1,other Zn treatments reduced the grain Zn biofortification index by 12.50%-47.02%,while relative to the control(Zn0),all Zn treatments decreased the Zn harvest index by 23.66%-60.44%.'Taihei 5'outperformed'Tailan 8'in grain Zn concentration,accumulation,utilization efficiency,and biofortification performance.Possibly influenced by precipitation,both types of colored-grain wheat performed better in the second growing season[Conclusion]Post-anthesis foliar Zn application effectively regulated Zn accumulation and partitioning in colored-grain wheat.The combination of purple-grained wheat varieties and foliar Zn application at 733 mg·L-1 achieved the optimal balance between grain Zn concentration and Zn utilization efficiency in colored-grain wheat systems.

Phosphorus fixation represents a primary constraint limiting the agronomic efficiency of phosphate fertilizers in calcareous soil. Rapeseed roots secrete amounts of organic matter, which can mobilize and decompose insoluble phosphorus in the soil. However, the activation mechanism of sparingly insoluble phosphorus in calcareous soils by rapeseed rhizosphere microorganisms remains unclear. This study aimed to screen and identify phosphate-solubilizing microorganisms from the rapeseed rhizosphere of calcareous soil, and to elucidate their key metabolic pathways for activating insoluble phosphorus. The results demonstrated that (i) fourteen dominant phosphate-solubilizing strains were isolated from rapeseed rhizosphere soil. Among these, Advenella alkanexedens was verified to significantly promote wheat growth and increase soil available phosphorus content. (ii) The culture condition optimization and functional characterization for Advenella alkanexedens revealed that its optimal growth temperature was 30°C, with an initial pH of 7. Its phosphate-solubilizing ability was regulated by Mg2+, K2+, and Ca2+ ions, and the strain exhibited considerable salt tolerance and the ability to produce siderophores. (iii) Advenella alkanexedens increased soil available phosphorus content by 11.49%-81.91% and elevated phytase activity by 36.87%-82.49%. Correlation analysis indicated that soil available phosphorus and phytase activity were significantly positively correlated with Ca2-P, Ca8-P, and Al-P fractions. (iv) Amino acids and organic acids were identified as the key metabolites influencing the phosphate-solubilizing function of Advenella alkanexedens. The KEGG pathway analysis showed these metabolites were primarily enriched in β-alanine metabolism and arginine and proline metabolism pathways. Our findings confirm that Advenella alkanexedens not only promotes crop growth but also significantly increases labile P fractions (Ca2-P, Ca8-P, Al-P) while reducing more stable forms (Ca10-P), thereby enhancing soil phosphorus use efficiency. This study holds important implications for planting rapeseed to activate insoluble phosphorus in soil, to reduce phosphate fertilizer application, and to promote sustainable utilization of soil phosphorus resources. Furthermore, it provides a theoretical foundation for developing agricultural microbial inoculants.IMPORTANCEOur results confirm that Advenella alkanexedens not only benefits crop growth but also converts insoluble phosphates (O-P, Ca10-P) into highly active inorganic phosphorus components, thereby enhancing the utilization efficiency of soil phosphorus. This study was of great significance in activating the insoluble phosphorus in the soil, reducing the input of phosphate fertilizers, achieving the sustainable utilization of phosphorus resources, and protecting the environment. Additionally, it provided a basis for developing agricultural microbial agents.

This study aimed to elucidate the biological mechanisms through which different tillage practices affect wheat yield and nutrient use efficiency under straw return conditions, focusing on rhizosphere microbial communities, metabolite profiles, and their interactions to inform improved agricultural management. The field experiment tested three treatments: no-tillage with all straw mulching (SN), rotary tillage straw return (SR), and plow tillage straw return (SP). Using high-throughput sequencing and liquid chromatography-tandem mass spectrometry, we investigated how different treatments affected the microbial community in wheat rhizosphere soil and metabolic functions through microbiome and non-targeted metabolomics analyses. SN helped to increase the wheat yield, soil nutrient content in the plow layer, and enzyme activity. Compared with SN, the yields were 8.3% and 12.4% lower under SR and SP, respectively, the soil organic carbon contents were 13.2% and 5.6% lower, and the pH values were 2.7% and 1.2% higher. Tillage practices significantly altered the composition and diversity of the bacterial and fungal communities. The species richness of bacterial and fungal communities followed the order of: SP > SR > SN and SN > SP > SR, respectively. The stabilities of the bacterial and fungal communities exhibited the same distribution pattern. Principal coordinate analysis and PERMANOVA indicated that under straw return, different tillage practices led to significant separation of soil bacterial and fungal communities. Furthermore, Actinobacteria and Proteobacteria contributed most significantly to differences in the bacterial community structures, and Ascomycota and Basidiomycota contributed most significantly to differences in the fungal community structures. Under straw return, different tillage practices significantly altered soil metabolite composition. Bacterial communities correlated more strongly with soil metabolites than fungal communities. Compared with SN, metabolic pathways for different metabolites were enriched under SR and SP, and all were related to amino acid metabolism, putatively mainly in the valine, leucine, and isoleucine biosynthesis pathways. Collectively, our findings demonstrate that tillage practice is a key regulator of straw-amended soil ecosystems, and that no-till with straw mulching optimizes yield and nutrient efficiency primarily by enhancing the functional synergy between the rhizosphere microbiome and metabolome.

Background Drought critically compromises agricultural productivity and threatens sustainable wheat production. Streptomyces pactum Act12 confers benefits to plant growth under drought stress, but its possible effects on root-associated microbiomes remain understudied. Here, shotgun metagenome sequencing and culture-dependent approaches were integrated to investigate the responses of rhizosphere and rhizoplane microbiomes in dryland winter wheat to exogenous S. pactum Act12 and their potential linkage to plant drought resistance. Results Seed biopriming with S. pactum Act12 increased plant aboveground dry weight at flowering (by 63.2%) and maturation (by 41.9%) stages, leading to improved grain yield (by 8.7%). Microbial inoculation reduced malondialdehyde contents in wheat leaves and roots at the flowering stage alongside compartment-specific alterations in soil microbiomes. Metagenomic analysis revealed inoculation-induced enrichment of distinct taxa in rhizosphere soils (flowering: Fibrobacterota, Altererythrobacter; maturation: Mucoromycota, Rhodospirillum) and rhizoplane soils (flowering: Pseudomonadota, Serratia; maturation: Candidatus_Pacebacteria, Variovorax). Functional profiling showed up-regulation of key pathways related to oxidative phosphorylation in inoculated rhizosphere soils at the flowering stage. In rhizoplane soils, ABC transporters and pyrimidine metabolism were up-regulated across stages upon inoculation. Two key strains isolated from rhizoplane soils, designated Glycomyces lechevalierae A4 and Microbacterium algeriense B3, demonstrated the ability to enhance drought resistance in wheat seedlings. Conclusions Inoculation of S. pactum Act12 heightens drought resistance in dryland winter wheat through compartment-specific phylogenetic restructuring and functional reprogramming of root-associated microbiomes.

To address the issue of inefficient soil water utilization in dryland wheat fields, caused by a mismatch between summer fallow precipitation and crop growth periods, implementing fallow-period tillage was crucial for conserving water and enhancing yield. However, there was a lack of comprehensive evaluations of the impact of different tillage practices on soil functional quality based on multidimensional indicators, and the relationship between yield and soil functional quality remained unclear. This study established three treatments during the summer fallow period: no tillage (FNT), subsoiling tillage (FST) and plowing tillage (FPT). We determined the soil water-stable aggregates particle size distribution and stability, aggregate organic carbon (AOC) content, soil organic carbon (SOC) content and storage (SOCs), as well as winter wheat yield. Using the Z-score method, we integrated the soil's physical and chemical indicators to perform a comprehensive evaluation of different tillage practices. The results showed that FNT significantly enhanced soil aggregate stability in the 0-30 cm soil depths compared to FST and FPT (p < 0.05), which was primarily attributed to a substantial increase in the content of >2 mm aggregates. Meanwhile, FNT resulted in significantly higher SOCs within the 0-50 cm profile, with increases of 8.1% and 5.8% compared to FST and FPT (p < 0.05), respectively. This was primarily due to elevated SOC content and higher AOC contents within the 2-0.25 mm and >2 mm aggregates in the topsoil layer. In contrast, FST significantly increased grain yield compared to FNT and FPT, by 16.7% and 15.0% (p < 0.05), respectively, which was associated with higher ear number and ear grains. A comprehensive evaluation using the Z-score method revealed that FNT achieved the highest soil functional quality score across the five layers. Therefore, no tillage during the summer fallow can enhance soil functional quality, primarily due to its positive impact on soil structure and carbon sequestration, but may not immediately increase crop yield.

Phosphorus deficiency in soil limits crop yields, especially in calcareous soil in arid and semi-arid areas of the Loess Plateau. Brassica napus L. can activate insoluble phosphorus in soil; however, the specific inorganic phosphorus components activated by rapeseed remain unclear. Field experiments were conducted in 2020, with rapeseed planted during the summer leisure period, to investigate the effect of rapeseed on phosphorus availability both before and after returning to the soil. Rapeseed was returned to the soil at two timings prior to winter wheat sowing: at flowering (F0) and 10 days after flowering (F10). The following treatments were applied: CK (no plants or fertiliser), N0P0 (no fertiliser), N150P0 (only N fertiliser), N150P60 (N + P2O5 [60 kg/ha]) and N150P120 (N + P2O5 [120 kg/ha]). Planting green manure during the summer fallow period after winter wheat harvest. Although rapeseed cultivation depletes the soil inorganic phosphorus pool, its incorporation increases soil total phosphorus and available phosphorus content by 14.3%-38.9%, respectively. The N150P60F0 treatment significantly enhances soil available phosphorus and alkaline phosphatase activity, thereby promoting phosphorus availability. After incorporation, the content of more active Ca2-P and Ca8-P in the soil increased, whereas the less soluble phosphorus fractions such as Al-P, Fe-P and O-P decreased. Early incorporation helps reduce the formation of poorly available Ca10-P, thereby enhancing soil phosphorus availability. N150P120F0 significantly increased soil bacterial and actinomycete counts, whereas fungal abundance was highest under the N150P60F0 treatment. Bacterial abundance showed a significantly positive correlation with soil available phosphorus and active phosphorus fractions (Ca2-P, Ca8-P), suggesting that bacteria play a key role in the phosphorus activation process driven by rapeseed straw return. Our results provide a theoretical basis for improving soil properties and enhancing soil phosphorus availability through rapeseed returning, thereby promoting efficient phosphorus utilisation by subsequent crops.

Tillage measures in the summer fallow phase cause soil disturbance and affect the vertical distribution of crop straw, thereby influencing variations in soil microbial structure and soil organic carbon (SOC). However, the specific mechanisms through which soil bacterial communities mediate SOC sequestration remain unclear. Therefore, we investigated the effects of no tillage (FNT), subsoiling tillage (FST), and plowing practice (FPT) in the summer fallow phase on soil properties, SOC stocks, soil extracellular enzymes, and bacterial community structures and functions. This study also identified the dominant factors in SOC accumulation processes. The results indicated that compared with FNT and FPT, FST significantly increased the 0-50 cm soil layer of SOC stock (7.6%-12.3%) due to the increase in the 0-30 cm soil depths. As well, FST markedly increased the soil amylase, beta-xylosidase, lignin peroxidase, beta-glucosidase, and sucrase activities at the 30-40 cm soil depth. These outcomes primarily stem from improvements in soil properties (e.g., mean weight diameter and geometric mean diameter). FNT and FST dramatically enhanced the bacterial community alpha diversity across the 30-40 cm soil layer compared with FPT. Partial least squares path modeling quantified the effects on SOC accumulation; soil water content exerted a significant negative effect (path coefficient, r = -0.249), whereas the mean weight diameter of soil aggregates (r = 0.354) and bacterial community alpha diversity (r = 0.603) exerted significant positive effects. Collectively, these factors moderate soil extracellular activities and affect SOC accumulation. Hence, subsoiling tillage in the summer fallow phase significantly improved soil structure, altered bacterial community diversity, and promoted the secretion of soil extracellular enzymes, thereby improving the carbon sequestration capacity. These results expand our understanding of the mechanisms underlying microbe-mediated carbon sequestration in dryland agriculture.

Modern agriculture faces a dual challenge: sustainable crop production and reducing the environmental impacts of excessive chemical fertilizers use, which leads to soil degradation, nutrient leaching and declining microbial diversity. Addressing these issues, biochar, a carbon-rich by product of pyrolysis, has emerged as a promising soil amendment due to its ability to enhance soil health, support nutrient cycling, and contribute to climate mitigation. However, its interactive effects with rhizosphere dynamics and soil enzymatic process, particularly when used with organic fertilizers, remain insufficiently explored. This review compiles current knowledge on the short-term and long-term impacts of biochar, particularly in combination with organic fertilizers, on rhizosphere properties, enzyme activities, and nutrient dynamics. In the short term, biochar improves soil structure, water retention, and microbial activity, while reducing nutrient leaching and increasing enzymatic functions. Over the long term, it facilitates carbon sequestration, stabilizes soil organic matter (SOM), and ensures nutrient availability, thereby promoting sustainable crop production. The synergistic application of biochar with organic amendments, such as compost and crop residues, further enhances soil fertility and ecosystem services. Despite its numerous benefits, the adoption of biochar on a larger scale is hindered by challenges related to cost-effectiveness, production consistency, and logistical constraints in diverse agricultural systems. Addressing knowledge gaps related to optimal feedstock selection, pyrolysis conditions, and application rates is essential for maximizing biochar’s potential. By integrating biochar into sustainable agricultural practices, farmers can enhance soil productivity, reduce environmental impacts, and contribute to climate change mitigation. A strategic and evidence-based implementation of biochar technologies holds promise for achieving long-term sustainability and food security goals.

In order to identify saline–alkali-tolerant rapeseed varieties suitable for cultivation on moderately saline–alkali soils and to expand the use of such lands, six rapeseed varieties were selected as experimental materials. Field experiments were conducted to evaluate agronomic traits, photosynthesis, stress physiology, yield, and quality throughout the entire growth period. Statistical methods, including correlation analysis, principal component analysis, membership function analysis, and cluster analysis, were employed to evaluate and select saline–alkali-tolerant varieties. The results indicated that H62 and 20C14 yielded the highest seed production, reaching 2287.99 kg·hm−2 and 2277.15 kg·hm−2, respectively. During the mid-to-late growth stages, the majority of agronomic traits, photosynthetic parameters, and stress physiology indicators for 20C14 were significantly superior to those of the other varieties. The results of the principal component analysis showed that the total root length at maturity stage, root–shoot ratio at flowering stage, and proline content at maturity stage were the most important indicators for screening saline–alkali-tolerant rapeseed varieties. A comprehensive analysis of these indicators revealed the following descending order of saline–alkali tolerance among the varieties: 20C14 > 20C17 > 20C4 > H62 > H158 > 17C2. Cluster analysis was performed to classify the rapeseed into strong saline–alkali-tolerant type (20C14 and 20C17), moderate saline–alkali-tolerant type (20C4, H62, and H158), and weak saline–alkali-tolerant type (17C2). Consequently, 20C14 and 20C17 are recommended as suitable rapeseed varieties for cultivation on soda saline–alkali soils.

Nitrogen is a critical nutrient for plant growth and productivity, but inefficiencies in its use in agriculture present both economic and environmental challenges. Enhancing nitrogen use efficiency (NUE) is essential for promoting sustainable crop production and mitigating the negative impacts of nitrogen loss, such as water pollution and greenhouse gas emissions. This review discusses various strategies aimed at improving NUE, with a focus on agronomic practices, genetic advancements, and integrated management approaches. Traditional agronomic methods, including split nitrogen application and the use of controlled-release fertilizers, are explored alongside precision agriculture techniques, which enable real-time adjustments to nitrogen application based on crop and soil conditions. Advances in genetics and biotechnology, such as conventional breeding, genetic modification, and genome editing, have contributed to the development of crop varieties with improved nitrogen uptake and assimilation. Additionally, the role of beneficial microbes, including nitrogen-fixing bacteria and mycorrhizal fungi, is highlighted as a natural means of enhancing nitrogen availability and reducing reliance on synthetic fertilizers. The review further emphasizes sustainable practices such as legume-based crop rotations, continuous cover cropping, and organic fertilization, which contribute to soil nitrogen enrichment and overall soil health. By combining these agronomic, genetic, and microbial strategies, a holistic nitrogen management approach can be achieved, maximizing crop yields while minimizing environmental impacts. This integrated strategy supports the development of resilient and sustainable agricultural systems, promoting long-term soil fertility and productivity.

Drought is a major obstacle to the development of naked oat industry. This work investigated mechanisms by which exogenous Streptomyces albidoflavus T4 and Streptomyces rochei D74 improved drought tolerance in naked oat (Avena nuda) seedlings. Results showed that in the seed germination experiment, germination rate, radicle and hypocotyl length of naked oat seeds treated with the fermentation filtrate of T4 or D74 under PEG induced drought stress increased significantly. In the hydroponic experiment, the shoot and root dry weights of oat seedlings increased significantly when treated with the T4 or D74 fermentation filtrate under the 15% PEG induced drought stress (S15). Simultaneously, the T4 treatment also significantly increased the surface area, volume, the number of tips and the root activity of oat seedlings. Both T4 and D74 treatments elicited significant increases in proline and soluble sugar contents, as well as the catalase and peroxidase activities in oat seedlings. The results of comprehensive drought resistance capacity (CDRC) calculation of oat plants showed that the drought resistance of oat seedlings under the T4 treatment was better than that under the D74 treatment, and the effect was better under higher drought stress (S15). Findings of this study may provide a novel and effective approach for enhancing plant defenses against drought stress.

Excessive use of inorganic fertilizers disrupts soil nutrient balance and leads to soil degradation and a decrease in biodiversity. In contrast, bio-fertilizers enhance soil structure and fertility and promote plant growth and sustainable agriculture development. Therefore, this study focused on a rotation system of winter wheat and summer maize and aimed to explore the effects of applying chemical fertilizer (NPK) and bio-fertilizer (BF) in the winter wheat season on the sustainable soil development of current wheat and subsequent maize. Before sowing winter wheat four fertilization treatments were, respectively CK (100% NPK at 750 kg ha−1), A (60% NPK at 450 + 20% BF at 150 kg ha−1), B (60% NPK at 450 + 40% BF at 300 kg ha−1), and C (60% NPK at 450 + 60% BF at 450 kg ha−1), conducted. The results showed that treatment A (60% NPK + 20% BF) replacing the NPK at 300 kg ha−1 with BF at 150 kg ha−1 significantly soil nutrient contents, enzyme activity, and microbial metabolic activity. The study also found a positive correlation between soil parameters (total nitrogen, alkaline nitrogen, available phosphorus, organic matter, urease, and alkaline phosphatase in the winter wheat and maize cropping season). Furthermore, the soil microbial composition showed significant enrichment of Proteobacteria, Acidobacteria, Actinobacteria, and Firmicutes, and variations among treatments. Moreover, the application of biofertilizer enhanced the diversity of soil fungi species, particularly during the winter wheat season. This study highlights the importance of integrating biofertilizers with NPK fertilizer for agricultural system conversion and promoting agricultural production and sustainability.

Anthocyanins and selenium (Se) have antioxidant properties and are crucial to human health. Previous works have well studied the role of exogenous Se fertilization in grain quality and anthocyanin formation in colored crops, whereas few reports on naturally Se-enriched colored grains exist. In this study, the quality, anthocyanin accumulation, and metabolism of natural Se-enriched purple waxy corn and common purple waxy corn were compared during kernel development. Natural Se-enriched purple waxy corn had higher concentrations of total Se, anthocyanins, flavones, starch (branched- and straightchain), and sugar than common purple waxy corn, and the optimum eating date was 28 days after pollination. Genes related to anthocyanin biosynthesis were significantly upregulated in natural Seenriched purple waxy corn, resulting in enriched anthocyanin metabolites (6-O-malonyl-beta-D-glu and 3-O-glu in Cy, Pn, and Pg). Most importantly, genetic alterations were observed which several genes and transcription factors were downregulated some branch pathways of lignin synthesis and accelerated anthocyanin synthesis. Our results profiled anthocyanin metabolism in naturally Se-enriched purple waxy corn to promote harvesting.

The aim of this study is to optimize the extraction process of oat saponins (Os) and to evaluate their antioxidant potential. Single factor experiment, response surface optimization design, and orthogonal test were employed to optimize the process of ultrasonic-assisted extraction of Os, and the optimal extraction conditions were as followed: ethanol volume fraction of 80 %, material-solvent ratio of 1:14, ultrasonic power of 400 W, ultrasonic time of 25 min, extraction temperature of 60℃, extraction time of 180 min, and the extraction rate of Os was 0.317 %±0.105 %. Using the method, the crude extract of Os was prepared and its abilities of scavenging radicals in vitro and inhibiting protein oxidation in pork were determined, with ascorbic acid (Vc) as the control. Results revealed that the scavenging ability of Os against DPPH radical, hydroxyl radical (·OH) and superoxide anion (O2–) increased with the concentration of Os. Interestingly, the scavenging abilities of Os against DPPH and O2– were far lower than that of Vc, but its scavenging ability against ·OH was very close to that of Vc, reaching 84.59 % and 96.33 %, respectively. Furthermore, the experiments of pork storage and Fenton oxidation system showed that Os with 0.09–0.72 mg/mL could reduce the production of carbonyl (8.49 %-50.05 %) and the oxidation of total sulfhydryl (1.29 %-25.86 %), and effectively inhibit the oxidation of protein in pork by 7.82 %–22.53 %. The results of this study will provide a theoretical basis for the application of oat saponins as a natural anti-protein oxidant in meat processing and storage.

Soil microbes are the main drivers of nutrient turnover in agro-ecosystems. The series of biochemical processes involved by these microorganisms are inseparable from the regulation of metabolites in the root-zone soils. Therefore, understanding the evolution of microbial communities driven by root-zone soil metabolites will help optimize agricultural management practices. Based on a field experiment, we explore the changes in soil properties, microbes, and metabolites under three tillage practices such as no-tillage with straw mulching (NTS), rotary tillage, and plough tillage with straw returning (RTS and PTS) based on untargeted metabolomics. We found that NTS helped to enhance nutrient contents and enzyme activities in the 0-20 cm soil layer. Specifically, compared with RTS and PTS, NTS increased grain yield by 6.4 % and 8.5 %, and SOC by 13.3 % and 5.7 %, respectively, but decreased pH by 2.8 % and 1.1 %. In addition, compared with NTS, RTS and PTS decreased the fungal richness by 16.5 % and 8.1 %, and decreased the fungal shannon index by 16.4 % and 9.2 %. However, tillage practices did not result in substantial differences in the alpha diversity of bacterial community. Both bacterial and fungal community composition were substantially affected by tillage practices and they were both significantly correlated with soil metabolites. In the symbiotic networks, NTS significantly increased the abundance of microorganisms with high connectivity, while RTS significantly increased the concentration of metabolites with high connectivity. Amino acids, as the main drivers, were significantly and positively associated with bacterial and fungal community composition, mainly enriched in the metabolic pathways of D - glutamine and D - glutamate metabolism and arginine and proline metabolism, and correlated with soil properties negatively and carbohydrates positively, directly or indirectly affecting soil microbial community composition. Our findings would provide new insight into metabolomics for the in-depth understanding of the metabolic mechanism for soil microbial community changes in dryland wheat fields under different tillage practices.

Organic fertilizers can partially replace chemical fertilizers to improve agricultural production and reduce negative environmental impacts. To study the effect of organic fertilizer on soil microbial carbon source utilization and bacterial community composition in the field of rain-fed wheat, we conducted a field experiment from 2016 to 2017 in a completely randomized block design with four treatments: the control with 100% NPK compound fertilizer (N: P2O5: K2O = 20:10:10) of 750 kg/ha (CK), a combination of 60% NPK compound fertilizer with organic fertilizer of 150 kg/ha (FO1), 300 kg/ha (FO2), and 450 kg/ha (FO3), respectively. We investigated the yield, soil property, the utilization of 31 carbon sources by soil microbes, soil bacterial community composition, and function prediction at the maturation stage. The results showed that (1) compared with CK, organic fertilizer substitution treatments improved ear number per hectare (13%-26%), grain numbers per spike (8%-14%), 1000-grain weight (7%-9%), and yield (3%-7%). Organic fertilizer substitution treatments increased the total nitrogen, available nitrogen, available phosphorus, and soil organic matter contents by 26%, 102%, 12%, and 26%, respectively, compared with CK treatments. Organic fertilizer substitution treatments significantly advanced the partial productivity of fertilizers. (2) Carbohydrates and amino acids were found to be the most sensitive carbon sources for soil microorganisms in different treatments. Particularly for FO3 treatment, the utilization of β-Methyl D-Glucoside, L-Asparagine acid, and glycogen by soil microorganisms was higher than other treatments and positively correlated with soil nutrients and wheat yield. (3) Compared with CK, organic fertilizer substitution treatments increased the relative abundance of Proteobacteria, Acidobacteria, and Gemmatimonadetes and decreased the relative abundance of Actinobacteria and Firmicutes. Interestingly, FO3 treatment improved the relative abundance of Nitrosovibrio, Kaistobacter, Balneimonas, Skermanella, Pseudomonas, and Burkholderia belonging to Proteobacteria and significantly boosted the relative abundance of function gene K02433 [the aspartyl-tRNA (Asn)/glutamyl-tRNA (Gln)]. Based on the abovementioned findings, we suggest FO3 as the most appropriate organic substitution method in rain-fed wheat fields.

Melatonin, a pleiotropic regulatory molecule, is involved in the defense against heavy metal stress. Here, we used a combined transcriptomic and physiological approach to investigate the underlying mechanism of melatonin in mitigating chromium (Cr) toxicity in Zea mays L. Maize plants were treated with either melatonin (10, 25, 50 and 100 μM) or water and exposed to 100 μM K2Cr2O7 for seven days. We showed that melatonin treatment significantly decreased the Cr content in leaves. However, the Cr content in the roots was not affected by melatonin. Analyses of RNA sequencing, enzyme activities, and metabolite contents showed that melatonin affected cell wall polysaccharide biosynthesis, glutathione (GSH) metabolism, and redox homeostasis. During Cr stress, melatonin treatment increased cell wall polysaccharide contents, thereby retaining more Cr in the cell wall. Meanwhile, melatonin improved the GSH and phytochelatin contents to chelate Cr, and the chelated complexes were then transported to the vacuoles for sequestration. Furthermore, melatonin mitigated Cr-induced oxidative stress by enhancing the capacity of enzymatic and non-enzymatic antioxidants. Moreover, melatonin biosynthesis-defective mutants exhibited decreased Cr stress resistance, which was related to lower pectin, hemicellulose 1, and hemicellulose 2 than wild-type plants. These results suggest that melatonin alleviates Cr toxicity in maize by promoting Cr sequestration, re-establishing redox homeostasis, and inhibiting Cr transport from the root to the shoot.

[目的]明确藜麦与豆科作物的间作效应,指导藜麦生产.[方法]采用随机区组设计,以藜麦、红豆、绿豆、黑豆4种作物单作为对照,设置藜麦/红豆、藜麦/绿豆、藜麦/黑豆3种间作模式,共计7个处理,探究藜麦与豆科作物间作对藜麦产量、植株养分以及土壤理化性质的影响.[结果](1)藜麦与3种豆科作物间作的土地当量比(LER)都大于1,其中藜麦/红豆间作的LER最高为1.52.(2)在藜麦生育期,藜麦/红豆提高了藜麦植株氮磷钾含量.(3)与藜麦单作相比,藜麦苗期间作处理均显著提高了土壤碱解氮、速效钾和全磷的含量,藜麦/红豆的碱解氮、有效磷、速效钾、有机质含量显著最高;藜麦成熟期间作处理均显著增加了土壤碱解氮、有效磷和全磷的含量,藜麦/绿豆的有效磷和全氮含量显著最高.(4)在藜麦苗期,藜麦/红豆的蔗糖酶、碱性磷酸酶和脲酶的活性显著最高.在藜麦成熟期,与藜麦单作相比,所有间作处理的蔗糖酶活性和碱性磷酸酶活性均显著增加,藜麦/红豆的蔗糖酶和脲酶活性显著最高.(5)回归分析表明,藜麦苗期的土壤磷酸酶活性与产量呈显著正相关;相关分析表明,藜麦成熟期的氮磷钾养分与大部分土壤养分呈显著正相关.[结论]藜麦与3种豆科作物间作对藜麦产量、植株养分、土壤养分、土壤酶活性都有提升,其中藜麦/红豆的提升效果最佳.

探索黑糯玉米硒吸收利用和营养品质对叶面喷施有机硒肥的响应，对生产中合理施用硒肥，进而支撑山西“特”“优”农业高质量发展具有重要意义。本研究以品种晋鲜糯8号为试验材料，于2020—2021年连续2年在山西晋中黑糯玉米典型种植区开展田间试验，设置一次喷施不同用量有机硒0、6和12 g Se hm -2 ，以及喷施量12 g Se hm -2 条件下分2次喷施，共4个处理，研究叶喷有机硒对黑糯玉米产量、硒吸收利用、籽粒花青素和铁锰铜锌含量的影响。结果表明，喷硒量和喷硒次数对黑糯玉米鲜食期产量和成熟期地上部生物量无影响。相比不喷硒，喷硒可提高鲜食期籽粒和成熟期地上部各器官硒含量、硒积累。喷硒12 g Se hm -2 时，籽粒硒含量达到满足人体硒营养需求的最低目标值100 μg kg -1 ，增幅最大，介于110～181 μg kg -1 。成熟期，植株各器官硒积累从高到低依次为叶片、籽粒、茎秆、苞叶、穗轴。喷硒12 g Se hm -2 ，分2次喷施的平均籽粒硒强化指数和籽粒硒回收率分别为6.95 (μg kg -1 ) (g hm -2 ) -1和2.4%，优于1次喷施。同时，鲜食期籽粒花青素和铁锰锌含量也最高，2年平均值分别为209、27.9、15.9和22.8 mg kg -1 ，但各处理间籽粒铜含量无差异。因此，兼顾硒吸收利用和籽粒营养品质同步提升，该区黑糯玉米生产中叶喷有机硒肥用量至少应不低于12 g Se hm -2 ，且分2次喷施效果较优。