SYL3-k increases style length and yield of F1 seeds via enhancement of endogenous GA4 content in Oryza sativa L. pistils.

KEY MESSAGE: SYL3-k allele increases the outcrossing rate of male sterile line and the yield of hybrid F1 seeds via enhancement of endogenous GA4 content in Oryza sativa L. pistils. The change in style length might be an adaptation of rice cultivation from south to north in the northern hemisphere. The style length (SYL) in rice is one of the major factors influencing the stigma exertion, which affects the outcross rate of male sterile line and the yield of hybrid F1 seeds. However, the biological mechanisms underlying SYL elongation remain elusive. Here, we report a map-based cloning and characterisation of the allele qSYL3-k. The qSYL3-k allele encodes a MADS-box family transcription factor, and it is expressed in various rice organs. The qSYL3-k allele increases SYL via the elongation of cell length in the style, which is associated with a higher GA4 content in the pistil. The expression level of OsGA3ox2 in pistils with qSYL3-k alleles is significantly higher than that in pistils with qSYL3-n allele on the same genome background of Nipponbare. The yield of F1 seeds harvested from plants with 7001SSYL3-k alleles was 16% higher than that from plants with 7001SSYL3-n allele. The sequence data at the qSYL3 locus in 136 accessions showed that alleles containing the haplotypes qSYL3AA, qSYL3AG, and qSYL3GA increased SYL, whereas those containing the haplotype qSYL3GG decreased it. The frequency of the haplotype qSYL3GG increases gradually from the south to north in the northern hemisphere. These findings will facilitate improvement in SYL and yield of F1 seeds henceforward.

OsSYL2AA , an allele identified by gene-based association, increases style length in rice (Oryza sativa L.).

Stigma characteristics are important factors affecting the seed yield of hybrid rice per unit area. Natural variation of stigma characteristics has been reported in rice, but the genetic basis for this variation is largely unknown. We performed a genome-wide association study on three stigma characteristics in six environments using 1.3 million single-nucleotide polymorphism (SNPs) characterized in 353 diverse accessions of Oryza sativa. An abundance of phenotypic variation was present in the three stigma characteristics of these collections. We identified four significant SNPs associated with stigma length, 20 SNPs with style length (SYL), and 17 SNPs with the sum of stigma and style length, which were detected repeatedly in more than four environments. Of these SNPs, 28 were novel. We identified two causal gene loci for SYL, OsSYL3 and OsSYL2; OsSYL3 was co-localized with the grain size gene GS3. The SYL of accessions carrying allele OsSYL3AA was significantly longer than that of those carrying allele OsSYL3CC . We also demonstrated that the outcrossing rate of female parents carrying allele OsSYL2AA increased by 5.71% compared with that of the isogenic line carrying allele OsSYL2CC in an F1 hybrid seed production field. The allele frequencies of OsSYL3AA and OsSYL2AA decreased gradually with an increase in latitude in the Northern Hemisphere. Our results should facilitate the improvement in stigma characteristics of parents of hybrid rice.

Anxiety and Depression of Nurses in a North West Province in China During the Period of Novel Coronavirus Pneumonia Outbreak.

PURPOSE: To investigate the anxiety and depression levels of frontline clinical nurses working in 14 hospitals in Gansu Province, China, during this period. DESIGN: A cross-sectional survey was conducted online between February 7 and 10, 2020, with a convenience sample of 22,034 nurses working in 14 prefecture and city hospitals in Gansu Province, located in northwest China. METHODS: A self-reported questionnaire with four parts (demographic characteristics, general questions related to novel coronavirus-infected pneumonia, self-rating anxiety scale, and self-rating depression scale) was administered. Descriptive statistics including frequencies, means, and SDs were computed. The associations between anxiety and depression with sociodemographic characteristics, work-related concerns, and impacts were analyzed, followed by multiple stepwise linear regression to identify factors that best predicted the nurses' anxiety and depression levels. FINDINGS: A total of 21,199 questionnaires were checked to be valid, with an effective recovery rate of 96.21%. The mean ± SD age of the respondents was 31.89 ± 7.084 years, and the mean ± SD length of service was 9.40 ± 7.638 years. The majority of the respondents were female (98.6%) and married (73.1%). Some demographic characteristics, related concerns, and impacts of COVID-19 were found to be significantly associated with both anxiety (p < .001) and depression (p < .001). Nurses who needed to take care of children or elderly relatives, took leave from work because they were worried about COVID-19, avoided contact with family and friends, and wanted to obtain more COVID-19-related knowledge had higher levels of both anxiety and depression. CONCLUSIONS: Results show that nurses faced with the COVID-19 outbreak are at risk for experiencing anxiety and depression. Demographic background, psychosocial factors, and work-related factors predicted the psychological responses. The family responsibilities and burdens of women may explain the higher levels of anxiety and depression among nurses with these obligations as compared to those without. On the other hand, nurses who chose not to take leave from work or who did not avoid going to work during this period were less anxious and depressed. CLINICAL RELEVANCE: Professional commitment might be a protective factor for adverse psychological responses. It is pertinent to provide emotional support for nurses and recognize their professional commitment in providing service to people in need.

Male-Produced Aggregation Pheromone of Coffee Bean Weevil, Araecerus fasciculatus.

The coffee bean weevil (CBW), Araecerus fasciculatus (De Geer, 1775), is a cosmopolitan stored-product pest, especially in tropical and subtropical areas. Previous reports showed evidence for aggregation behavior of CBW and this study aimed to identify and evaluate the aggregation pheromone of this pest. Whole-body solvent extractions were analyzed by coupled gas chromatography-mass spectrometry and comparison of male and female extracts showed a male-specific compound which was identified as squalene, 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene. This compound was shown to attract male and female CBW in Y-tube olfactometer and storage trap assays. The longevity of septum lures was also evaluated in a warehouse. Squalene could be useful in monitoring and controlling this pest.

Growth and comprehensive quality index of tomato under rain shelters in response to different irrigation and drainage treatments.

The effects of two levels of irrigation water (100%, 60%) and buried underground pipe depths (0.8 m, 0.6 m) under rain shelters' conditions on yield and some quality parameters of tomato were investigated. A fully randomized factorial experiment was conducted between April and August in 2011 and 2012 at Hohai University. It was found that drainage treatments enhanced biomass production, whereas soil desiccation led to biomass reduction. At 60 cm buried underground pipe depths, the drought treatments increased the mean root weight and root-shoot ratio by 14% and 39%, respectively. The main effects of drainage treatments on the fruit quality were increases in total soluble solids (TSS), soluble sugar (SS), and vitamin C (VC) compared to the control. In addition, drainage treatments increased the average yield by 13% and 9%, respectively, in both years. The drought treatments did not significantly alter fruit yield, although mean single fruit weight was slightly reduced. Instead, these treatments tend to have great potential to improve fruit quality (TSS, SS, and VC) to variable extents. In both years, the drought treatment at 60 cm buried underground pipe depths proved to possess the highest comprehensive quality index based on Principal Component Analysis.

Emergy evaluation of a production and utilization process of irrigation water in China.

Sustainability evaluation of the process of water abstraction, distribution, and use for irrigation can contribute to the policy of decision making in irrigation development. Emergy theory and method are used to evaluate a pumping irrigation district in China. A corresponding framework for its emergy evaluation is proposed. Its emergy evaluation shows that water is the major component of inputs into the irrigation water production and utilization systems (24.7% and 47.9% of the total inputs, resp.) and that the transformities of irrigation water and rice as the systems' products (1.72E + 05 sej/J and 1.42E + 05 sej/J, resp.; sej/J = solar emjoules per joule) represent their different emergy efficiencies. The irrigated agriculture production subsystem has a higher sustainability than the irrigation water production subsystem and the integrated production system, according to several emergy indices: renewability ratio (%R), emergy yield ratio (EYR), emergy investment ratio (EIR), environmental load ratio (ELR), and environmental sustainability index (ESI). The results show that the performance of this irrigation district could be further improved by increasing the utilization efficiencies of the main inputs in both the production and utilization process of irrigation water.

Dumbbell structure probe-triggered rolling circle amplification (RCA)-based detection scaffold for sensitive and specific neonatal infection-related small extracellular vesicle (sEV) detection.

Small extracellular vesicles (sEVs) have been reported to play important roles in cell-to-cell communication and are promising biomarkers for the early diagnosis of infections. Therefore, it is in high demand to develop a method that can integrate easy-to-operate sEV isolation and sensitive quantification. We herein propose a novel detection scaffold for sEV isolation via low-speed centrifugation and the quantification of sEVs through DNAzyme-based signal amplification. The detection scaffold is established through dumbbell probe-based RCA (rolling circle amplification), containing repeated CD63 aptamer sections and DNAzyme sections. The original state of the DNAzyme section is locked in a hairpin structure in the detection scaffold. In the presence of sEVs, the CD63 aptamer recognizes and binds with sEVs, leading to the aggregation of sEVs, which can be isolated by low-speed centrifugation and the exposure of the DNAzyme section. After the catalytic fluorescence signal generation from the DNAzyme-based molecular beacon (MB) cleavage, the method exhibited a detection range of 102 to 106 particles per µL. Considering the high sensitivity and wash-free and easy-to-operate features, the strategy reported herein paves a new avenue for the effective determination of sEVs and other membrane biomolecules in fundamental and applied research.

Construction of Dual-Target Recognition-Based Specific MicroRNA Detection Method for Acute Pancreatitis Analysis.

MicroRNAs (miRNAs) play crucial roles in regulating various biological processes and are considered promising biomarkers for clinical diagnosis and therapy of acute pancreatitis. Herein, we present a duplex-specific nuclease (DSN enzyme) and DNAzyme-assisted fluorescent miRNA detections assay that can provide improved detection specificity due to a design of dual-target recognition and a comparable sensitivity. The dual-target recognitions are composed of (i) miRNA unfold hairpin structure toehold to form DNA-RNA duplex, among which the DNA section will be digested by DSN enzyme, releasing miRNA to participant in a next recycle. (ii) After DNAzyme-based nicking site formation in loop section of molecular beacon (MB), miRNA can bind with the loop section of MB and gradually unfold MB probe, generating fluorescence signals. With this general principle, distinct discrimination capability towards even one base pair mismatch of homogenous miRNA is obtained, showing a promising prospect in clinical diagnosis and therapy of acute pancreatitis.

Aggressive intravenous hydration protocol of Lactated Ringer's solution benefits patients with mild acute pancreatitis: A meta-analysis of 5 randomized controlled trials.

Objective: The aim of this meta-analysis was to determine the role of an aggressive intravenous hydration protocol of Lactated Ringer's solution in patients with mild acute pancreatitis (MAP). Methods: A systematic search was conducted in PubMed, EMBASE, Cochrane Library, and China National Knowledge Infrastructure (CNKI) to identify randomized controlled trials (RCTs) published before August 19, 2022. The clinical outcomes were evaluated using the standard mean difference (SMD), mean difference (MD), risk ratio (RR), and 95% confidence interval (CI). The primary outcome was clinical improvement, while the secondary outcomes were the development of systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS), relief of epigastric abdominal pain, and length of hospital stay (LoH). Statistical analysis was performed with RevMan 5.4. Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) Working Group system was used to determine the quality of evidences. Results: There were five RCTs with 370 MAP patients included, and the overall methodological quality was moderate. Aggressive hydration protocol was comparable to standard hydration protocol in terms of clinical improvement (RR = 1.33, 95%CI = 0.95-1.87, P = 0.10; very low evidence). Fewer events of SIRS (RR = 0.48, 95%CI = 0.31-0.72, P < 0.001; low evidence) and MODS (RR = 0.34, 95%CI = 0.13-0.91, P = 0.03; moderate evidence) were reported in patients receiving aggressive hydration protocol. Meanwhile, aggressive hydration protocol also significantly relieved epigastric abdominal pain (SMD = -0.53, 95%CI = -0.81 to -0.25, P < 0.001; low evidence) and shorten the LoH (MD = -2.36, 95%CI = -3.17 to -1.55, P < 0.001; low evidence) compared with standard hydration protocol. Conclusion: For patients with MAP, aggressive hydration protocol may be more effective than standard hydration protocol at lowering SIRS and MODS rates, relieving epigastric abdominal pain, and shortening the LoH. Due to the small number of studies that are eligible and poor methodological quality of eligible studies, further studies are required to validate our findings.

Meta-analysis of visual pretreatment for the prevention of emergence delirium in children undergoing ophthalmic surgery.

Objective: To evaluate the role of visual pretreatment in preventing emergence delirium in children receiving ophthalmic surgery. Methods: Four randomized controlled trials were identified in four databases, and a meta-analysis was conducted using RevMan 5.3. Results: The meta-analysis demonstrated a significantly lower incidence of postoperative emergence delirium (risk ratio: 0.39; 95% CI: 0.31-0.49) and propofol rescue (risk ratio: 0.29; 95% CI: 0.13-0.65) but comparable modified Yale Preoperative Anxiety Scale score (mean difference: -3.66; 95% CI: -9.96 to 2.65) and incidence of adverse events in the visual pretreatment group. Conclusion: Visual pretreatment is effective in preventing postoperative emergence delirium in children undergoing ophthalmic surgery without significant adverse effects and can also decrease the incidence of propofol rescue.

Liquid-phase synthesis of cyanuric acid from urea.

The focus of this paper was to identify a cheaper solvent from among diesel fuel, kerosene, sulfolane or a mixture of sulfolane and cyclohexanol for the preparation of cyanuric acid heterocyclization of urea. To obtain a higher yield, the effects of catalyst (sodium, ammonium, calcium and zinc salts) and temperature (160 degrees C to 220 degrees C) on the trimerization of urea were also carefully studied. We established the optimal reaction conditions and further validated them in our scale-up experiments.

[Effects of soil structure improvement on chlorophyll fluorescence parameters and yield of rice in a coastal reclamation region]. / æµ·æ¶‚åœŸå£¤ç»“æž„æ”¹è‰¯å¯¹æ°´ç¨»å¶ç»¿ç´ è§å ‰å‚æ•°å’Œäº§é‡çš„å½±å“.

To examine the effects of soil structure improvement due to the amendment of biochar and polyacrylamide (PAM) on the chlorophyll fluorescence characteristics of rice leaves and the yield of rice, a pit cultivation experiment was carried out in a coastal reclamation region. Three levels of biochar (0%, 2% and 5% by the mass of 0-20 cm surface soil and noted as B1, B2 and B3, respectively) and PAM (0‰, 0.4‰ and 1‰ by the mass of 0-20 cm surface soil and noted as P1,P2 and P3, respectively) were applied to the adopted soil, respectively. The results of the three-year experiment showed that an appropriate application quantity of biochar and PAM could improve the fluorescence characteristics of rice leaves. However, high levels of biochar and PAM had no obvious or even a negative effect. Among all the treatments, the B2P2 treatment always had the highest the maximum photochemical efficiency (Fv/Fm), the actual photochemical efficiency of photosystem II (ΦPS2), the photochemical quenching coefficient (qP) and the non-photochemical quenching coefficient (NPQ) values during the whole growth period. The chlorophyll content (SPAD value) of rice leaves showed no significant difference among different biochar application levels. However, it showed significant differences among different PAM application levels, with the highest value under the soil amended with 0.4‰ PAM (the P2 treatment). The application of biochar and PAM had significant impacts on rice yield, with the highest yield, namely 7236 kg·hm-2, presenting under the B2P2 treatment, which was 28.5% higher than that of the control. The improved soil structure of the coastal saline soil due to the amendment of biochar and PAM affects rice yield mainly through its influences on the 1000-grain weight, the spike number per hole, the grain number per spike and the seed setting rate. It is concluded that improving soil structure by applying an appropriate quantity of biochar and PAM is conducive to increase the chlorophyll fluorescence characteristics and the yield of rice in the coastal reclamation region.

Synthesis and bioactivity studies of sex pheromone analogs of the diamond back moth, Plutella xylostella.

BACKGROUND: Diamondback moth, Plutella xylostella L., is a very important pest of cruciferous vegetables causing excessive economic losses worldwide. Bioactivities of halo-, diazo-, and cyclopropane acetates of P. xylostella sex pheromone have been evaluated using electrophysiology and enzyme inhibition assays. RESULTS: A total of 23 sex pheromone analogs of P. xylostella were designed and synthesized and the result shows that (11Z)-hexadec-11-en-1-yl 2,2,2-trifluoroacetate, (11Z)-hexadec-11-en-1-yl 2,2,3,3,3-pentafluoropropanoate, and (11Z)-hexadec-11-en-1-yl trifluoromethanesulfonate elicited potential inhibitory effects at all doses tested in the electrophysiology and enzyme inhibition assays. Interference of locating the sex pheromone source was found strongest when these three analogs were mixed with the sex pheromone at a 10:1 ratio. In addition, field test showed that the rate of mating disruption was over 90% when (11Z)-hexadec-11-en-1-yl 2,2,2-trifluoroacetate or (11Z)-hexadec-11-en-1-yl 2,2,3,3,3-pentafluoropropanoate was mixed with the sex pheromone at a 10:1 ratio. CONCLUSION: Two sex pheromone antagonists were screen out by electrophysiology, enzyme inhibition assays, wind tunnel and field tests. We believe that these antagonists could be used to establish a novel eco-friendly measure to control P. xylostella and provide evidence for clarifying the specific functions and molecular mechanisms of sex pheromone antagonists. © 2018 Society of Chemical Industry.

Effects of vegetative filter strip on overland flow nitrogen and phosphorus intercepting under different inflow conditions.

The vegetative filter strips can effectively intercept erosion of water and sediment on the slope, with huge potential to prevent and control soil erosion and agricultural non-point source pollution. A series of muddy water scouring experiments under different inflow conditions in the indoor soil trays were conducted to investigate the effects of vegetative filter strip (VFS) on intercepting nitrogen (N) and phosphorus (P) under different inflow conditions and its internal hydrological responses. The results showed that the VFS could effectively intercept N and P in the runoff. When the inflow was 200, 400, 600 L·h-1, the intercepting rates were 74.9%, 62.0%, 58.3% for N and 85.0%, 75.6%, 72.0% for P, respectively. The best intercepting effect occurred at the lower inflow rates. Different inflow N and P concentrations had no significant effect on N and P interception efficiency. Under different inflow conditions, the intercepting rates of N and P by VFS increased with the increases of Froude value with a significant linear positive correlation. However, there were linear negative correlations between the intercepting rate and resistance coefficient, shear stress and stream power. The relationship between the N and P intercepting rates and shear stress was the best among others, and the N and P intercepting rates could be well predicted by a formula containing shear stress.

[Impact of Exogenous Nitrogen Import on Sediment Denitrification and N2O Emissions in Ditches Under Different Land Uses].

Farmland drainage ditch soil can consume part of the agricultural non-point nitrogen through nitrification-denitrification processes. Paddy fields, vegetable land, and orchards are the main types of land uses in the Taihu Lake region, and many drainage ditches are distributed across these lands. The way exogenous nitrogen is imported to drain ditches under different land uses differs significantly, which can directly affect the nitrogen consumption ability of the channels. A soil incubation experiment was conducted under laboratory conditions to study the denitrification loss and N2O emissions of drainage ditch soil under different land uses. In this study, drainage ditch sediment was collected from orchards, paddy fields, and vegetable land in the Taihu Lake region. Five different NO3--N content import levels were set:0, 0.5, 1.0, 5.0, and 10 mg·L-1, which were denoted as N0, N1, N2, N3, and N4, respectively. The results showed that exogenous nitrogen input stimulated sediment denitrification in the drainage ditches. The sediment denitrification rates of the three types of channels increased significantly with the increase of input NO3--N concentration (P<0.05). There was a significant linear positive correlation between the cumulative denitrification loss and input NO3--N concentration (R2>0.75). Excluding for the vegetable land sediment, the N2O emission rate and cumulative emissions did not increase significantly with the increase of input NO3--N concentration (P>0.05). There was no significant difference in the denitrification and N2O emissions among the three kinds of channel sediment, with no or low exogenous nitrogen input (N0and N1) (P>0.05). As the input NO3--N concentration increased, especially under the condition of high exogenous nitrogen input (N3and N4), the nitrogen consumed via denitrification in orchard and paddy field sediment was significantly higher than that in vegetable land sediment (P<0.05), whereas the N2O emissions of drainage ditch sediment from the vegetable land was significantly higher than that of the other two channel sediments (P<0.05). The mineralization rate of ditch soil organic carbon had a positive correlation with denitrification rate (n=15), and microbial mineralization (CO2-C) promoted the nitrification and denitrification of the drainage ditch soils.

[Effects of biochar and PAM application on saline soil hydraulic properties of coastal reclamation region]. / æ–½ç”¨ç”Ÿç‰©ç‚­å’Œèšä¸™çƒ¯é °èƒºå¯¹æµ·æ¶‚å›´åž¦åŒºç›ç¢±åœŸæ°´åŠ›æ€§è´¨çš„å½±å“.

Disc infiltration tests were carried out to study the soil infiltration characteristics under different rates of soil amendments application, and to investigate the effects of biochar and polyacrylamide (PAM) application on saline soil hydraulic properties, pore characteristics and contribution of each pore to soil water flow in coastal reclamation region. The results showed that soil satura-ted hydraulic conductivity increased by 46.4% when biochar was applied at 2% compared with the control, and decreased with increasing PAM application. The total effective soil porosity and r>100 µm pores were increased by 8.3% and 10.2% (P<0.05) with the application of 2% biochar alone. The total effective soil porosity and different radius pores decreased with the PAM application. Particularly, the total effective soil porosity decreased markedly when PAM was applied at 1‰ and the reduction was up to 88%. With the application of biochar and PAM, the contribution of r<100 µm pores to water flow decreased and the pores with r>500 µm played a major role in determining water flows.

Favorable Marker Alleles for Panicle Exsertion Length in Rice (Oryza sativa L.) Mined by Association Mapping and the RSTEP-LRT Method.

The panicle exsertion length (PEL) in rice (Oryza sativa L.) is an important trait for hybrid seed production. We investigated the PEL in a chromosome segment substitution line (CSSL) population consisting of 66 lines and a natural population composed of 540 varieties. In the CSSL population, a total of seven QTLs for PEL were detected across two environments. The percentage of phenotypic variance explained (PVE) ranged from 10.22 to 50.18%, and the additive effect ranged from -1.77 to 6.47 cm. Among the seven QTLs, qPEL10.2 had the largest PVE, 44.05 and 50.18%, with an additive effect of 5.91 and 6.47 cm in 2015 and in 2016, respectively. In the natural population, 13 SSR marker loci were detected that were associated with PEL in all four environments, with the PVE ranging from 1.20 to 6.26%. Among the 13 loci, 7 were novel. The RM5746-170 bp allele had the largest phenotypic effect (5.11 cm), and the typical carrier variety was Qiaobinghuang. An RM5620-RM6100 region harboring the EUI2 locus on chromosome 10 was detected in both populations. The sequencing results showed that the accessions with a shorter PEL contained the A base, while the accessions with a longer PEL contained the G base at the 1,475 bp location of the EUI2 gene.

[Denitrification Loss and N2O Emission from Different Carbon Inputs in Orchard Drains Sediments].

The orchard is an important economic crop in Taihu Lake region. Heavy nitrogen application in orchard results in great nitrogen loss to drainage ditch, and unbalanced carbon nitrogen ratio. Therefore, carbon might be an important limiting factor for sediment nitrification and denitrification. A soil incubation experiment controlled by the acetylene inhibition method was conducted under laboratory conditions to study the denitrification loss and N2O emissions of orchard drainage ditch soil. We designed five carbon input levels of 0, 5, 25, 50 and 100 mg·L-1, which were noted as C0, C1, C2, C3 and C4, respectively, meanwhile there was 5 mg·L-1 net nitrogen input in the form of KNO3 in each treatment. The results showed that carbon inputs could stimulate both denitrification rates (DN) and N2O emission rates. Carbon and nitrogen ratio had a significant effect on N2O emission rates and denitrification loss rates (P<0.05). When the carbon and nitrogen ratio was 10:1, total cumulative denitrification losses and N2O emissions were both highest (319.26 µg·kg-1 and 6.20 µg·kg-1, respectively) among the treatments, which accounted for 1.28% and 0.02% of net nitrogen input, respectively. This result indicated that the carbon and nitrogen ratio of 10:1 was most favorable for N2O emissions and denitrification process in sediments.

[Effects of Biochar Amendment and Irrigation on Denitrification Losses in Greenhouse Tomato Fields].

Biochar addition and irrigation are normal farm practices for tomatoes management, while their impacts on denitrification are less known. In this study, three irrigation treatments(hereafter main plots)were set as 50% (W50%), 75% (W75%) and 100% (W100%) of reference evapotranspiration (ET0), and the subplots coupled three biochar treatments at the rates of 0 (B0), 25 t·hm-2 (B25) and 50 t·hm-2 (B50). Typical soil samples in each plot were collected when tomatoes were harvested in 2014 and 2015. We used acetylene inhibition method to study the denitrification loss, and also measured N2O emissions of tomato soil without acetylene amendment. The results showed that biochar and irrigation significantly changed the physical and chemical properties of the soil. Adding biochar improved total carbon, total nitrogen content and pH of the soil, while reduced the content of NH4+-N and NO3--N compared to B0. On the contrary, irrigation reduced the amount of total nitrogen and total carbon content. As a result, both biochar and irrigation significantly reduced denitrification losses (P<0.05). Moreover, the interaction of biochar and irrigation significantly reduced soil inorganic nitrogen and denitrification losses (P<0.05),and the orders of the influencing factors of NO3--N were irrigation, biochar, their interactions in turn, the orders of the influencing factors of NH4+-N were biochar, irrigation, their interactions in turn, the orders of the influencing factors of denitrification losses were irrigation, biochar, their interactions in turn. Denitrification losses were positively related to inorganic nitrogen content in the soil, CO2mineralization rates and N2O emission rates. The ratio of N2O/DN, ranging from 0.31% to 1.88%, was significantly affected by biochar and irrigation treatment in the fields (P<0.05).