The plant growth regulator 5-aminolevulinic acid (5-ALA) mitigates mild to moderate abiotic stresses. However, its efficacy and mode of action under extreme combined stress conditions remain poorly understood. This study investigated the unconventional effects of 5-ALA on maize (Zea mays L.) subjected to severe drought-flood abrupt alternation (DF) using integrated transcriptomic, proteomic and targeted phytohormone analyses. We discovered that 5-ALA unexpectedly accelerated plant wilting and mortality. While severe DF stress itself triggered a profound energy crisis by inhibiting photosynthetic carbon fixation and glycolysis, 5-ALA treatment specifically and strongly activated the jasmonic acid biosynthesis pathway and downstream energy-intensive defence programs, particularly phenylpropanoid and flavonoid biosynthesis. Multi-omics integration revealed that this forced activation of defence synthesis occurred under irreversible energy supply collapse, co-occurring with induced endoplasmic reticulum stress, inhibition of ribosomal protein synthesis and initiation of programmed cell death. Our findings provide the first systemic evidence that 5-ALA can act as a 'double-edged sword', pushing plants into a critical 'defense overgrowth-energy depletion' dilemma under extremely energy-deficient conditions. This study redefined the application boundaries of 5-ALA and highlighted the primacy of plant energy status in determining the outcomes of chemical interventions.

To address freshwater scarcity in agriculture, the use of brackish and reclaimed water for alternate irrigation has emerged as a viable alternative. This study evaluated four biochars (rice husk, peanut shell, rice straw, and wheat straw, applied at 2%) and three silicon fertilizers (Lang-Si (S1), Nayou-Si (S2), and sodium metasilicate pentahydrate (S3)) as amendments for sandy loam soil (Lang-Si, Nayou-Si, foliar spray at 1000 & times; dilution; sodium metasilicate pentahydrate, foliar spray at 150 mg center dot L-1). Their effects on soil salinity, physicochemical properties, and microbial community structure were assessed under alternate irrigation with brackish and reclaimed water. Alternate irrigation reduced soil electrical conductivity and increased total phosphorus (TP) content compared to single-source irrigation. The effects of amendments varied by type. Biochars improved soil fertility and reduced salinity: peanut shell biochar decreased EC by 15.5%; rice husk biochar increased total nitrogen (TN), TP, and organic matter (OM) by 11.8%, 8.2%, and 10.1%, respectively; and wheat straw biochar elevated subsurface soil TN and OM by 14.1% and 40.0%. Straw-derived biochars and sodium metasilicate pentahydrate maintained higher bacterial alpha-diversity (Shannon index >= 6.67). These effects corresponded with the nutrient adsorption capacity of biochars and the ionic stress alleviation by soluble silicon. The correlation analysis identified OM, TN, TP, and EC as the key drivers shifting the microbial community. Straw-derived biochars and sodium metasilicate pentahydrate are suitable amendments for alternate irrigation systems. These materials balance salinity control, fertility improvement, and microbial conservation, offering practical options for sustainable use of brackish and reclaimed water in agriculture.

While previous studies have suggested that biochar, nitrification inhibitors, and urease inhibitors may reduce soil greenhouse gas emissions, their effectiveness in soils irrigated with alternative water resources remains unclear. To compensate for this, reclaimed water and livestock wastewater were utilized as alternative water resources alongside groundwater control. Nitrapyrin and N-(n-butyl) thiophosphoric triamide and biochar were applied to the soil either individually or in combination, and a no-substance treatment (NS) was included for comparison. The results revealed that reclaimed water and livestock wastewater irrigation exacerbated the global warming potential. Compared to the NS, all exogenous substance treatments suppressed nitrous oxide (N2O) emissions while increasing carbon dioxide (CO2) emissions, and affecting methane (CH4) emissions varied across treatments irrespective of the water types. Interestingly, the additional biochar reduced the inhibitory effect of the inhibitors on the greenhouse effect. Using nitrification inhibitors reduced the global warming potential by 48.3% and 50.1% under reclaimed water and livestock wastewater irrigation, respectively. However, when nitrification inhibitors were applied in combination with biochar, the global warming potential was increased by 52.1–83.4% compared to nitrification inhibitors alone, and a similar trend was also observed in the scenario of urease inhibitors, with increases ranging from 8.8 to 35.1%. Therefore, the combined application of biochar and inhibitors should be approached cautiously, considering the potential for increased greenhouse gas emissions.

Reclaimed water and sewage sludge as renewable resources are urged to be used in agriculture, but their reuse poses potential chemical and microbiological risks. As a waste biomass resource, sludge combined with reclaimed water irrigation is a major way to develop and utilize renewable resources and control environmental pollution. However, whether reclaimed water irrigation and sludge application have adverse effects on the agricultural environment and human health remains a controversial point of discussion. A greenhouse pot experiment was conducted to investigate the effects of reclaimed water and sewage sludge on rhizosphere soil and root endophytic bacterial communities, the abundance of selected genes, and to evaluate the soil quality of sludge application. The results of this study demonstrated that the application of sewage sludge could result in the accumulation of nutrients in soil. The rhizosphere soil and root endophytic bacteria possessed common dominant groups at phylum level, including Proteobacteria, Bacteroidota, Actinobacteriota and Chloroflexi. Reclaimed water irrigation had less effect on rhizosphere soil and root endophytic bacterial communities than sludge application. Pseudomonas showed a decrease in relative abundance in both rhizosphere soil and root endophytes following sludge application, whereas beneficial bacteria like Bacillus, Stenotrophobacter, Cellvibrio and Altererythrobacter experienced an increase. Redundancy analysis (RDA) showed that the diversity and composition of bacterial communities in rhizosphere soil among treatment groups were closely related to soil organic matter, total nitrogen and total phosphate contents. The functional prediction highlighted the participation of functional groups in nitrogen and carbon cycling as well as degradation processes at varying sludge application rates. The abundance of selected genes was more affected by sludge application. A considerable amount of sludge application to the soil resulted in a significant increase in the abundance of pathogens and antibiotic resistance genes, as well as functional genes, compared to unamended soil with sludge treatment. Direct or excessive application of sludge might aggravate the dissemination and accumulation of deleterious genes in soil-crop systems irrigated with reclaimed water. Overall, our study results may provide valuable information on how sludge influences the microbial community characteristics and abundance of specific genes, guiding the assessment of biological quality and the appropriate use of sludge in agriculture irrigated with reclaimed water.

Rational utilization and improvement of agricultural water resources has been and is still the focus of research on developing efficient and green agriculture in various countries. Thus, the exploitation and usage of non-traditional water resources hold substantial significance in water resources management and sustainable agriculture. However, their reuse may induce secondary soil salinization and impose stress on crops. To address the challenges of soil salinity and plant stress under brackish-reclaimed water irrigation, this study aimed to investigate the effects of silicon (Si) fertilizer application on soil properties and Pak choi ( Brassica rapa L.) performance under two cycling irrigation sequences (RW-BW and RW-RW-BW) and three spraying frequencies (0-, 2-, and 4-day intervals). The findings displayed that the pH of each treatment (7.95-8.10) remained below 8.5, suggesting no risk of secondary soil alkalization. At the same spraying frequency of silicon fertilizer, the soil electrical conductivity (EC) significantly decreased with increasing irrigation times of reclaimed water. Silicon fertilizer improved soil structure and reduced sodium levels, alleviating salinity. The increasing spraying interval of silicon fertilizer provoked the diminution of the SAR and ESP, before rising again. But they were far below the threshold range, and there was no risk of soil salinization (15% and 13 mM 1/2 ). The total silicon content of the soil and leaves increased under the different cycling irrigation conditions. Spraying silicon fertilizer on the crop leaf surface did not significantly influence the total silicon content of the soil. In conclusion, the application of Si-fertilizer beneficially impacts soil physicochemical properties and crop development and mitigates the risk of secondary salinization under brackish-reclaimed water for cycling irrigation.

Salinization severely impairs crop growth by inducing oxidative stress and disrupting cellular homeostasis. This study systematically investigates the synergistic effects of salt-tolerant plant-growth-promoting rhizobacteria (ST-PGPR) and foliar silicon fertilizer spraying (FSFS) on antioxidant responses in Pak choi under salt stress. Two-season pot experiments were carried out to evaluate key indicators, including antioxidant enzyme activities (superoxide dismutase: SOD; peroxidase: POD; catalase: CAT), oxidative stress (malondialdehyde: MDA), osmolyte accumulation (proline, soluble protein), and hormones (Jasmonic Acid: JA; Salicylic Acid: SA; Abscisic acid: ABA). The results demonstrate that combining ST-PGPR with FSFS significantly enhances SOD (6.18–2353.85%), POD (3.44–153.29%), and CAT (25.71–319.29%) activities while reducing MDA content (8.12–35.87%). Proline and soluble protein levels increased by 1.56–15.71% and 5.03–188.87%, respectively. Hormonal regulation increased JA, SA, and ABA levels by 1.05–31.81%, 2.09–34.29%, and 3.18–30.09%, respectively. Notably, ST-PGPR treatments at 104 and 106 cfu·mL−1, combined with foliar silicon application, consistently ranked highest in overall antioxidant performance across both seasons based on a principal component analysis. These findings provide novel insights into microbial–mineral interactions for sustainable saline agriculture.

The application of nitrification inhibitors (nitrapyrin) and urease inhibitors (N-(N-butyl) thiophosphoric triamide) under conventional water resources has been considered as an effective means to improve nitrogen utilization efficiency and mitigate soil greenhouse gas emissions. However, it is not known whether the inhibitors still have an inhibitory effect under unconventional water resources (reclaimed water and livestock wastewater) irrigation and whether their use in combination with biochar improves the mitigation effect. Therefore, unconventional water resources were used for irrigation, with groundwater (GW) control. Nitrapyrin and N-(N-butyl) thiophosphoric triamide were used alone or in combination with biochar in a pot experiment, and CO2, N2O, and CH4 emissions were measured. The results showed that irrigation of unconventional water resources exacerbated global warming potential (GWP). All exogenous substance treatments increased CO2 and CH4 emissions and suppressed N2O emissions, independent of the type of water, compared to no substances (NS). The inhibitors were ineffective in reducing the GWP whether or not in combination with biochar, and the combined application of inhibitors with biochar further increased the GWP. This study suggests that using inhibitors and biochar in combination to regulate the greenhouse effect under unconventional water resources irrigation should be done with caution.

Farmland ammonia (NH3) volatilization is an important source of NH3, and the application of chemical fertilizer nitrogen (N) is the main factor affecting NH3 volatilization. The optimal substitution of chemical fertilizer with organic manure and straw reportedly reduces NH3 volatilization, while reducing irrigation increases NH3 volatilization. However, the combined effect of nitrogen fertilizer substitution and reducing irrigation on NH3 volatilization and the role of microorganisms in this process remains unclear. In a soil column experiment, NH3 volatilization and microbial composition were measured under both multiple N sources and different irrigation levels by the vented-chamber method and metagenomic sequencing. The results revealed that multiple N sources application reduced cumulative NH3 volatilization by 16.5–75.4% compared to single chemical fertilizer application, and the decreasing trend of NH3 volatilization under reduced irrigation conditions was greater. Microorganisms had a more important effect on NH3 volatilization of reduced irrigation than conventional irrigation. The abundance of nirA, arcC, E3.5.1.49, and E3.5.5.1 (ammonia-producing) genes varied significantly at the two irrigation levels. Overall, multiple N sources could inhibit NH3 volatilization increasing under reducing irrigation compared to a single chemical fertilizer. Our findings contribute valuable insights into the combined effect of reduced irrigation and multiple N sources on NH3 volatilization.

Water resource shortage has become an important factor limiting agricultural sustainability in China. In addition, the development and utilization of unconventional water resources are greatly important for alleviating agricultural water resource deficit. The Pakchoi was cultivated by using the surface soil (0–20 cm) from the field in this pot experiment. The experiment lasted for approximately 1 month to study microbial community structure variation under brackish water and reclaimed water irrigation. The 16S rDNA high-throughput assays revealed that soil bacteria mainly consisted of Proteobacteria and Actinobacteria at the Phylum level, along with Arenimonas and Nocardioides at the Genus level under mixed irrigation with brackish water and reclaimed water. In summary, irrigation with pure reclaimed water promoted part of microbial communities and irrigation with pure brackish water inhibited the growth and activities of certain microbial communities. We found that mixed irrigation improved the microbial community structure diversity compared with that in response to pure brackish water irrigation, while decreased the community structure diversity compared with that in response to fresh water irrigation and pure reclaimed water irrigation.

【Background】Cadmium (Cd) is one of contaminants found in agricultural soils caused by anthropogenic activities including wastewater irrigation and application of phosphate fertilizers rich in Cd impurities, sludges and composts. In China, Cd contamination comes to the top in soils contaminated by all heavy metals and their metalloids. Since Cd is toxic to all organisms and highly mobile in soil for plants to take up, excessive Cd accumulation in crop tissues could impede its growth and even lead to mortality. Numerous studies showed that adding exogenous substances to soil could alleviate toxic effects of Cd on crops, but if and how their efficacy varies with crop variety remains poorly understood. 【Objective】Taking winter wheat as an example, this paper aimed to investigate the effects of exogenous Si, Ca, Mg and humic acid on uptake of Cd by different cultivars and its subsequent translocation at seedling stage. 【Method】Wheat varieties Bainong 419 (419) with high Cd accumulation in grain and Bainong 418 (418) with low Cd accumulation in grain were taken as the model plants. They were grown in hydroponic culture with the Cd content in it spiked to 10 mg/L or 30 mg/L respectively. We added Si, Ca, Mg and humic acid at different rates to the medium and harvested the crops 30 days later. We then measured Cd accumulation and transportation in roots and shoots, as well as root morphology traits. 【Result】Crop absorption of Cd varied with the wheat varieties, and the total length, surface area, volume and tip number of the roots in both varieties decreased with the increase in Cd concentration. Compared to variety 418, variety 419 took more Ca for its root developments. At low Cd concentration and compared to CK, adding Si at low dose improved root growth of the variety 419 and reduced Cd accumulation in its roots and shoots, while adding other elements inhibited root growth; applying humic acid at high dose enhanced Cd accumulation in the roots. It was found that compared to CK, adding any exogenous element reduced Ca content in the roots of the variety 419 when Cd concentration was low. For the variety 418 grown in medium with low Cd concentration, adding Si and Ca was more effective to promote root growth than adding Si alone, while adding Mg and humic acid did not show noticeable effects. Adding Si reduced Cd accumulation in roots and shoots at significant level, while adding Ca and Mg only impeded Cd accumulation in the root. Humic acid did not appear to have a noticeable impact on plant Cd. For the crops growing in medium with high Cd concentration, adding Si boosted root growth of both varieties regardless of its application rate, while in contrast, adding other elements were unable to alleviate Cd toxicity to plants at significant level. Compared with other treatments, adding Si at high does significantly increased the translocation factor (TF) for both varieties growing in medium with low Cd concentration, and it was also effective at boosting the TF for the variety 419 growing in medium with high Cd concentration. 【Conclusion】The most effective conditioner to alleviate Cd toxicity to winter wheat was Si, although its efficacy varies with wheat cultivar, Si application rate and Cd concentration in the medium where the crop grows.

Treated livestock wastewater reuse for irrigation and straw return in arid regions have become common practices worldwide. However, many uncertainties still exist regarding the effects of the returning straw sizes on heavy metal accumulation in soil and plants under treated livestock wastewater irrigation. In a pot experiment growing maize and soybean, large (5–10 cm), medium (1–5 cm), and small (<1 cm) sizes of wheat straw were amended to assess the changes in Cu and Zn distribution in the rhizosphere, bulk soils, and plants. Groundwater and swine wastewater were used as irrigation water resources. The results showed that irrigation with swine wastewater significantly reduced soil pH and increased the concentration of soil-available potassium. Concentrations of Cu in soil were more sensitive to swine wastewater and straw application than those of Zn in soil. Swine wastewater irrigation increased the accumulation of Cu and Zn in plants with higher concentrations of Zn, while straw return tended to inhibit this increase, especially when a small size of straw was employed. In addition to providing a reference for revealing the interaction mechanism between swine wastewater irrigation and straw return, this study proposes feasible solutions to improve the efficiency of agricultural waste recycling and realize sustainable agricultural development.

Not only is solving freshwater resource shortages effective but also an important measure for realizing the sustainable development of agriculture through the development and use of unconventional water resources. This pot experiment investigated the role of exogenous silicon in the risk of secondary soil salinization and the growth physiology of Lvxiu pakchoi cabbage under irrigation by using brackish water alone (BW), reclaimed water alone (RW), and compound irrigation with brackish water and reclaimed water at a ratio of 1:1, as well as the distribution of silicon in a soil–crop system. The results showed that with the extension of the spraying period of silicon fertilizer, the electrical conductivity (EC) decreased under 1:1 compound irrigation. The pH values in all treatments ranged from 7.95 to 8.10 without a potential risk of alkalization. Spraying silicon fertilizer had a positive effect on increasing the ratio of exchangeable potassium to sodium in soil. Spraying silicon fertilizer significantly reduced the percentage of exchangeable sodium (ESP) and the sodium adsorption ratio (SAR) in soils irrigated using BW, and increased the soil ESP and SAR under compound irrigation and RW irrigation, but these factors did not exceed the threshold of soil salinization. The proper application of silicon fertilizer had no significant effect on the total silicon content in the soil but increased the total silicon content in the plants to some extent. In addition, the yield was improved through proper silicon fertilizer application. In summary, exogenous silicon has positive effects on soil physical and chemical properties and crop growth, and relieves secondary salinization risk under compound irrigation via brackish water and reclaimed water.

The reduction of greenhouse gas releases from agricultural systems is of great significance in mitigating climate change. It is necessary to implement measures to mitigate carbon dioxide (CO2) and methane (CH4) emissions from soils irrigated using alternative waters, promoting the reuse of livestock wastewater and reclaimed water. The use of nitrapyrin, a nitrification inhibitor, and N-(N-butyl) thiophosphoric triamide, a urease inhibitor, has been explored to reduce greenhouse gas emissions. However, the impact of the inhibitor application on the soil carbon cycle as well as CO2 and CH4 emissions under alternative water irrigation remains unclear. To address this, a pot experiment with two consecutive cycles, irrigated with reclaimed water, livestock wastewater, and groundwater control was conducted. Nitrapyrin and/or N-(N-butyl) thiophosphoric triamide were applied to investigate the impacts of inhibitors on carbon cycle functional genes, soil properties, and CO2 and CH4 releases under alternative water irrigation. The results showed that inhibitor application increased the enrichment level of carbon degradation functional genes (xylA and cdh) and CO2 emission in the first cycle of this experiment, but had the opposite effect in the second cycle, regardless of the water type. The effects of increasing the relative abundance of methane-oxidizing genes (mmoX and mxaF) and lessening CH4 emissions were more pronounced when the nitrification inhibitor was applied alone. The combined application of inhibitors did not significantly promote the suppression of CO2 and CH4 emissions compared to a single application. Based on the structural equation model, soil NH4+-N and labile organic carbon were identified as key factors influencing the enrichment level of carbon cycle functional genes, as well as CO2 and CH4 emissions. This study suggests that soil labile organic carbon may influence the modulation of CO2 and CH4 releases by inhibitors and that multiple cycles of studies should be adopted when assessing the environmental impacts of inhibitors and alternative water irrigation.

Agricultural utilization of reclaimed water is considered to be an effective way to solve water shortage and reduce water environmental pollution. Silicon fertilizer can improve crop yield and quality and enhance crop resistance. The effect of foliar spray with silicon fertilizer on phyllosphere microbial communities remains lacking. In this study, a pot experiment was conducted to explore the effects of different types of silicon fertilizer on the composition and diversity of a phyllosphere bacterial community and the abundances of related functional genes in rice irrigated with reclaimed water. The results showed that Firmicutes, Proteobacteria, Actinobacteriota, Bacteroidota, and Verrucomicrobiota dominated the phyllosphere bacteria of rice. The relative abundance of Bacillus was higher than that of other treatments in RIS3. Reclaimed water irrigation significantly increased the relative abundances of the potential pathogens Pantoea and Enterobacter. The unclassified bacteria were also an important part of the bacterial community in the rice phyllosphere. Bacillus, Exiguobacterium, Aeromonas, and Citrobacter were significantly enriched by silicon fertilizer treatments. Functional prediction analysis showed that indicator species were mainly involved in metabolism and degradation functions, and the predicted functional groups of phyllosphere bacteria were attributed to chemoheterotrophy, aerobic chemoheterotrophy, nitrate reduction, and fermentation. Quantitative PCR results showed that AOA, AOB, and nifH genes were at low abundance levels in all treatments, and nirK genes was not significantly different among treatments. These results contribute to the in-depth understanding of the effects of foliar spray silicon fertilizer on the bacterial community structure and diversity of rice phyllosphere and provide a theoretical basis for the application of silicon fertilizer in reclaimed water irrigation agriculture.

The deep migration of soil nitrogen (N) poses a significant risk of N leaching, contributing to non-point-source pollution. This study examines the influence of microbial networks on the deep migration of chemical fertilizer N under varying irrigation management and multiple N fertilizer sources. A soil column experiment with eight treatments was conducted, utilizing 15N isotope labeling and metagenomic sequencing technology. The findings revealed that reduced irrigation significantly curbs the deep migration of chemical fertilizer N, and straw returning also mitigates this migration under conventional irrigation. Microbial network complexity and stability were markedly higher under reduced irrigation compared to conventional practices. Notably, network node count, average degree, and modularity exhibited significant negative correlations with the deep migration of chemical fertilizer N. The network topology indices, including node count, average clustering coefficient, average degree, modularity, and edge count, were found to be relatively more important for the deep migration of chemical fertilizer N. In conclusion, microbial networks play an important role in reducing the deep migration of chemical fertilizer N.

The adsorption behaviors and transfer pathways of antibiotics in plant–soil system are greatly influenced by the electrochemical properties of both soil particles and plant roots. However, the effects of roots electrochemical properties on antibiotic adsorption are largely unknown. Here, the fresh soybean, maize, and wheat roots with different electrochemical properties were obtained from hydroponic cultivation, and the adsorption processes and mechanisms of doxycycline, tetracycline, sulfadiazine, and norfloxacin on roots under various environmental conditions were investigated. Results showed that the adsorption amount of antibiotics on roots increased with the initial concentration of antibiotics. The coexisting low–molecular weight organic acids and anions inhibited the antibiotic adsorption on roots. The soybean roots performed strong adsorption ability compared with the maize and wheat roots driven by the variations in root electrochemical properties. This study demonstrates the significance of electrochemical interactions between antibiotics and roots in plant–soil system and can contribute to the more accurate risk assessment and effective pollution control of antibiotics.

The scarcity of freshwater resources has increased the use of nonconventional water resources such as brackish water, reclaimed water, etc., especially in water-scarce areas. Whether an irrigation cycle using reclaimed water and brackish water (RBCI) poses a risk of secondary soil salinization to crop yields needs to be studied. Aiming to find an appropriate use for different nonconventional water resources, pot experiments were conducted to study the effects of RBCI on soil microenvironments, growth, physiological characteristics and antioxidation properties of crops. The results showed the following: (1) compared to FBCI, the soil moisture content was slightly higher, without a significant difference, while the soil EC, sodium and chloride ions contents increased significantly under the RBCI treatment. With an increase in the reclaimed water irrigation frequency (Tri), the contents of EC, Na+ and Cl− in the soil decreased gradually, and the difference was significant; the soil moisture content also decreased gradually. (2) There were different effects of the RBCI regime on the soil’s enzyme activities. With an increase in the Tri, the soil urease activity indicated a significant upward trend as a whole. (3) RBCI can alleviate the risk of soil salinization to some extent. The soil pH values were all below 8.5, and were without a risk of secondary soil alkalization. The ESP did not exceed 15 percent, and there was no possible risk of soil alkalization except that the ESP in soil irrigated by brackish water irrigation went beyond the limit of 15 percent. (4) Compared with FBCI, no obvious changes appeared to the aboveground and underground biomasses under the RBCI treatment. The RBCI treatment was conducive to increasing the aboveground biomass compared with pure brackish water irrigation. Therefore, short-term RBCI helps to reduce the risk of soil salinization without significantly affecting crop yield, and the irrigation cycle using reclaimed-reclaimed-brackish water at 3 g·L−1 was recommended, according to the experimental results.

【Objective】 Constructed wetland is a biotechnological technique to treat wastewater; its function depends on a multitude of biotic and abiotic factors. This paper compares the performance of eight wetlands constructed by different materials. 【Method】 The eight wetlands we studied were constructed by fine sand only (CK), fine sand + corn straw powder (JW), fine sand + industry glucose (PW), sand + corn-straw biochar (SW), fine sand + eisenia fetida (KQ), fine sand + corn straw powder + eisenia fetida (JQ), fine sand + industrial glucose + eisenia fetida (PQ), fine sand + corn stover biochar + eisenia fetida (SQ), respectively. 【Result】 Adding corn-straw biochar, industrial glucose and corn-straw power increased the COD removal rate by 81.80%, 88.58% and 85.77%, respectively, compared to CK. Adding industrial glucose combined with corn straw powder improved purification efficiency of total N (TN) and total P (TP) by 7.0% and 2.8%, respectively. Wetland with industrial glucose and corn straw powder had the best TN removal rate, reaching 98% and 98.2%, respectively. Adding corn-straw power along with eisenia fetida was most effective to remove cooper, compared with other treatments. On average, introducing eisenia fetida to the wetlands increased the removal rates of COD, Cu and Zn by 1.8%, 6.3% and 2.6%, respectively, while adding corn-stover biochar significantly increased the removal rate of NH4+-N. Compared with corn straw powder and corn straw biochar, industrial glucose was more efficient for removing COD, total N and N, and Cu. 【Conclusion】 Adding eisenia fetida and organic carbon to the wetland can improve its efficacy to remove COD, nitrogen and heavy metals, especially corn-stover powder combined with eisenia fetida. For removing Cu, corn straw powder combined with eisenia fetida works the best.

In order to explore the reasonable utilization of brackish water and reclaimed water in areas with insufficient freshwater resources, three treatments were set, including reclaimed water irrigation（T1）, mixed irrigation of 1∶1 with brackish water-reclaimed water（T2） and brackish water irrigation（T3）, and local groundwater irrigation（CK2） was taken as the control, of which the saline degree of brackish water was 5 g/L. Based on the pot experiments, soil water content, soil salt content, soluble ions contents and soil enzyme activities including soil sucrase（S-SC）, soil alkaline phosphatase（S-AKP/ALP）, soil urease（S-UE） were measured. The responses of soil enzyme activities to the effect of brackish water and reclaimed water mixed irrigation was evaluated by the second generation integra-ted biological response(IBR v2 ) index method. The results indicate that:（1） With the increase of the proportion of brackish water in the mixture of brackish water and reclaimed water, the soil moisture content and salt content are higher.（2）The effects of mixed irrigation using brackish water-reclaimed water on soil enzyme activities are different. The soil alkaline phosphatase and urease activities under mixed irrigation are higher than that of brackish water irrigation and reclaimed water irrigation, and the soil sucrase activity is slightly lower than that of reclaimed water irrigation, but higher than that of brackish water irrigation.（3）Based on the IBR v2 index method, compared with CK, the deviation of enzyme activity caused by T1 treatment is the lowest, and the IBR v2 value is 2.12, followed by T2 treatment, the IBR v2 value is 2.42, and the highest deviation appeares in T3 treatment with the IBR v2 of 2.92. The activities of S-AKP/ALP, S-SC and S-UE are inhibited in T3 treatment. T2 treatment could induce the activity of S-AKP/ALP and S-UE, but slightly inhibite S-SC activity. T1 treatment induce the activity of S-AKP/ALP and S-SC, but slightly inhibite the activity of S-UE to a certain extent. Therefore, based on IBR v2 , and considering soil enzyme activity and the limitations of reclaimed water resources such as large amount of reclaimed water resources and small daily discharge, reclaimed water and brackish water, it can be considered to used reclaimed water together with brackish water in arid and water shortage areas.

Abstract Background Microvascular dysfunction is one of the most common pathological characteristics in Type 2 diabetes. Human mesenchymal stem cell-derived exosomes (hUCMSCs-Exo) have diverse functions in improving microcirculation; however, the molecular mechanism of hUCMSCs-Exo in regulating burn-induced inflammation is not well understood. Methods hUCMSCs-Exo were extracted by hypervelocity centrifugation method, and exosome morphology was observed by transmission electron microscopy, exosome diameter distribution was detected by particle size analysis, and exosome specific proteins were identified by Western blot.2. DB/DB mice were randomly divided into exosomes group and PBS group. Exosomes and PBS were injected into the tail vein, respectively, and the calf muscle tissue was taken 28 days later. 0.5% Evans blue fluorescence assessment microvascular permeability. The expression of CD31 was detected by immunofluorescence.The morphology and function of microvessels in muscle tissue of lower limbs was evaluated by transmission electron microscopy.3. TMT proteomics was used to detect the changes of differential protein expression in lower limb muscle tissues of the PBS group and the exosome group, and data analysis was performed to screen key signal molecules and their involved biological pathways. Key signal molecules CD105 were verified by Western blot. The expression of TGF-β1 in exosomes were evaluated by Western blot. Results Electron microscopy showed that hUCMSCs-Exo presented a uniform vesicle structure, and NTA showed that its diameter was about 160 nm. Western blot showed positive expression of specific proteins CD9, CD81 and TSG101 on exosomes.2. There is no significant change in blood glucose and body weight before and after the exosome treatment. The exosome group can significantly reduce the exudation of Evans blue. Compared with the PBS group. Meanwhile, CD31 immunofluorescence showed that the red fluorescence of exosome treatment was significantly increased, which was higher than that of PBS group. Transmission electron microscopy showed smooth capillary lumen and smooth and complete surface of endothelial cells in the exosome group, while narrow capillary lumen and fingerlike protrusion of endothelial cells in the PBS group.3.Quantitative analysis of TMT proteomics showed that there were 82 differential proteins, including 49 down-regulated proteins and 33 up-regulated proteins. Go enrichment analysis showed that the differential proteins were involved in molecular function, biological process, cell components,among which CD105 was one of the up-regulated proteins. Through literature search, CD105 was found to be related to endothelial cell proliferation. Therefore, this study verified the changes of CD105 in the exosome group, and it was used as the mechanism study of this study. 4. Western blot analysis showed that the expression of CD105 protein in lower limb muscle tissue of exosome group was significantly increased compared with that of PBS group. Based on the fact that CD105 is a component of the TGF-β1 receptor complex and exosomes are rich in growth factors and cytokines, this study further examined the expression of TGF-β1 in exosomes, and the results showed that exosomes had high expression of TGF-β1. Conclusion By improving the integrity of microvascular endothelial cells, hUCMSCs-Exo can improve the permeability of microvessels in diabetic lower muscle tissue, further promote the proliferation of lower limb muscle cells and inhibit the apoptosis of tissue cells. The mechanism may be associated with exosomes rich in TGF-β1, which is likely to promote endothelial cell proliferation and improve permeability through binding to the endothelial CD105/TβR-II receptor complex, while promoting angiogenesis and protecting skeletal muscle cells from apoptosis.