Calcium-Magnesium Ca/Mg Ratios and Their Agronomic Implications for the Optimization of Phosphate Fertilization in Rainfed Rice Farming on Acidic Ferralsol in the Forest Zone of Ivory Coast

This study is a contribution to improving rice productivity on acidic plateau soils of the tropical rainforest zone. It is based on taking into account the cationic balances of the soil in order to optimize the phosphorus (P) nutrition of rice on these acidic soils, where this nutrient constitutes a limiting factor for agricultural production. Three (3) pot trials were conducted in Adiopodoumé in the forested south of Côte d’Ivoire. The interactive effects of calcium carbonate (0, 25, 50 and 75 kg Ca ha−1) and magnesium sulfate (0, 25, 50 and 75 kg Mg ha−1) were evaluated on the response of NERICA 5 rice at doses 0, 25, 50 and 75 kg P ha−1 of natural phosphate from Togo, applied only once at the start of the experiment. Additional fertilizers of nitrogen (N) (100 kg N ha−1) and potassium (K) (50 kg KCl ha−1) were added to each of the tests in a split-plot device. The test results revealed a paddy production potential of approximately 3 to 5 t⋅ha−1 for NERICA 5 on an acidic soil, under the effect of the interaction of P, Ca and Mg. The quadratic response of rice yield to the doses of these fertilizers would be more dependent on their balance, itself influenced by Ca nutrition. For the sustainability and maintenance of rice production in agro-ecology studied, it was recommended doses of 38 kg Ca ha−1, 34 kg Mg ha−1 in a Ca/Mg ratio (1/1) with intakes of 41 kg P ha−1, overall in a ratio 1/1/1 (P/Ca/Mg) more favorable to the availability of free iron considered a guiding element of mineral nutrition. Thus, these promising results should be confirmed in a real environment for better management of the fertilization of rice cultivated on acidic plateau soils in Côte d’Ivoire.

Effect of citric acid on microstructure and electrochemical characteristics of high voltage anodized alumina film formed on etched Al Foils

Aluminum capacitor foils with a tunnel etch structure were reacted with boiling water and then anodized at 530 V in boric acid solution or boric acid＋citric acid mixed solution.The microstructure and crystallinity of the resulting anodized film were examined by TEM and XRD.The special capacitance,resistance and withstanding voltage of the film were explored with electrochemical impedance spectroscopy（EIS）,LCR meter and small-current charging.The results show that the high voltage anodized oxide film consists of an inner layer with high crystallinity and an outer layer with low crystallinity.However,the crystallinity of the film formed in boric acid＋citric acid mixed solution is higher than that of the film formed in only boric acid solution,leading to an increase in film＇s field strength and special capacitance.Meanwhile,there are more defects from phase transformation in the out layer of the film formed in boric acid＋citric acid mixed solution than in that of film formed in only boric acid solution,leading to a decrease in film＇s resistance and withstanding voltage.

富里酸和Ca^(2+)共存对嗜酸性氧化亚铁硫杆菌介导生成次生高铁矿物的影响

为揭示富里酸和Ca^(2+)共存对嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)氧化酸性矿山废水(AMD)中的Fe^(2+)和形成次生高铁矿物的影响,分析了pH、Fe^(2+)氧化率、铁沉淀率以及次生高铁矿物矿相、基团等相关指标。结果表明,Ca^(2+)确实具有提高嗜酸性氧化亚铁硫杆菌氧化Fe^(2+)的能力。低质量浓度(0.2 g/L)的富里酸对嗜酸性氧化亚铁硫杆菌活性的提高具有促进作用,高质量浓度(0.4 g/L)的富里酸具有抑制作用,而增加Ca^(2+)反过来能够减弱高浓度富里酸对嗜酸性氧化亚铁硫杆菌的抑制作用。对形成的次生高铁矿物进行X射线衍射(XRD)和傅立叶红外光谱(FTIR)分析,结果表明高浓度富里酸促进了另一次生高铁矿物草黄铁矾的生成。

Corrosion resistance of Mg-Al-LDH steam coating on AZ80 Mg alloy:Effects of citric acid pretreatment and intermetallic compounds

In this study,the effects of intermetallic compounds(Mg_(17)Al_(12)and Al_(8)Mn_(5))on the Mg-Al layered double hydroxide(LDH)formation mechanism and corrosion behavior of an in-situ LDH/Mg(OH)_(2)steam coatings on AZ80 Mg alloy were investigated.Citric acid(CA)was used to activate the alloy surface during the pretreatment process.The alloy was first pretreated with CA and then subjected to a hydrothermal process using ultrapure water to produce Mg-Al-LDH/Mg(OH)_(2)steam coating.The effect of different time of acid pretreatment on the activation of the intermetallic compounds was investigated.The microstructure and elemental composition of the obtained coatings were analyzed using FE-SEM,EDS,XRD and FT-IR.The corrosion resistance of the coated samples was evaluated using different techniques,i.e.,potentiodynamic polarization(PDP),electrochemical impedance spectrum(EIS)and hydrogen evolution test.The results indicated that the CA pretreatment significantly influenced the activity of the alloy surface by exposing the intermetallic compounds.The surface area fraction of Mg_(17)Al_(12)and Al_(8)Mn_(5)phases on the surface of the alloy was significantly higher after the CA pretreatment,and thus promoted the growth of the subsequent Mg-Al-LDH coatings.The CA pretreatment for 30 s resulted in a denser and thicker LDH coating.Increase in the CA pretreatment time significantly led to the improvement in corrosion resistance of the coated AZ80 alloy.The corrosion current density of the coated alloy was lower by three orders of magnitude as compared to the uncoated alloy.

Influence of Ca/P ratio on the catalytic performance of hydroxyapatite for decarboxylation of itaconic acid to methacrylic acid

Methacrylic acid,an important organic chemical,is commercially manufactured starting from fossil feedstock.The decarboxylation of itaconic acid derived for biomass is a green route to the synthesis of methacrylic acid.In view of the problems existing in the researches on this route such as use of noble metal catalyst,harsh reaction conditions and low desired-product yield,we prepared a series of hydroxyapatite catalysts with different Ca/P molar ratios and evaluated their catalytic performance.The results showed that the hydroxyapatite catalyst with a Ca/P molar ratio of 1.58 had the best catalytic activity.The highest yield of MAA up to 61.2%was achieved with basically complete conversion of itaconic acid under the suitable reaction conditions of 1 equivalent of NaOH,2 MPa of N_(2),250℃,and 2 h.On this basis,a reaction network for the decarboxylation of itaconic acid to methacrylic acid catalyzed by hydroxyapatite was established.With the aid of catalyst characterization using X-ray powder diffraction,NH3/CO2 temperature-programmed desorption,N_(2)physisorption,inductively coupled plasma optical emission spectrometry,and scanning electron microscopy,we found that the distribution of surface acid sites and basic sites,crystal growth orientation,texture properties and morphology of hydroxyapatite varied with the Ca/P molar ratio.Furthermore,the change of the crystal growth orientation and its influence on the surface acidity and alkalinity were clarified.

High-temperature stress suppresses allene oxide cyclase 2 and causes male sterility in cotton by disrupting jasmonic acid signaling

Cotton(Gossypium spp.) yield is reduced by stress. In this study, high temperature(HT) suppressed the expression of the jasmonic acid(JA) biosynthesis gene allene oxide cyclase 2(GhAOC2), reducing JA content and causing male sterility in the cotton HT-sensitive line H05. Anther sterility was reversed by exogenous application of methyl jasmonate(MeJA) to early buds. To elucidate the role of GhAOC2 in JA biosynthesis and identify its putative contribution to the anther response to HT, we created gene knockout cotton plants using the CRISPR/Cas9 system. Ghaoc2 mutant lines showed male-sterile flowers with reduced JA content in the anthers at the tetrad stage(TS), tapetum degradation stage(TDS), and anther dehiscence stage(ADS). Exogenous application of MeJA to early mutant buds(containing TS or TDS anthers) rescued the sterile pollen and indehiscent anther phenotypes, while ROS signals were reduced in ADS anthers. We propose that HT downregulates the expression of GhAOC2 in anthers, reducing JA biosynthesis and causing excessive ROS accumulation in anthers, leading to male sterility. These findings suggest exogenous JA application as a strategy for increasing male fertility in cotton under HT.

CRISPR/Cas-等温扩增技术在食源性病原菌检测中的研究进展

食源性病原菌引起的食品安全事件引起广泛关注,为保证食品安全,采取有效的检测手段至关重要。新兴的簇状规则间隔短回文重复序列(clustered regularly interspaced short palindromic repeats,CRISPR)及其关联蛋白(CRISPR-associated protein,Cas)组成的CRISPR/Cas系统是广泛存在于细菌和古细菌中的一种获得性免疫系统,可高效、特异性识别并切割外源核酸,与传统技术相比在检测病原菌方面更为高效。本文基于CRISPR/Cas生物传感系统-等温扩增技术联用的相关研究进行综述,对CRISPR/Cas系统的分类、原理以及与等温扩增耦合后在食源性病原菌检测方面的研究进展进行概述,并对其在即时检测应用中的前景以及所面临的挑战进行深入探讨,以期为CRISPR/Cas生物传感系统的进一步发展提供参考。

Effects of Citric Acid on Hydration Process and Mechanical Properties of Thermal Decomposed Magnesium Oxychloride Cement

In order to make full use of salt lake magnesium resources and improve the strength of the thermal decomposed magnesium oxychloride cement （TDMOC）, the effects of citric acid on the hydration process and mechanical properties of TDMOC was studied. The hydration heat release at initial 24 h and strengths at 3, 7, and 28 days of TDMOC specimens were conducted. The hydration products and paste microstructure were analyzed by XRD, FT-IR and SEM, respectively. The results showed that citric acid can not only reduce the 24 h hydration heat release and delay the occurring time of second peak of TDMOC, but also produce more 5Mg（OH）z.MgC12.SH20 and less Mg（OH）2 in hydration process of TDMOC. More perfect and slender crystals were observed in the microstructure of the TDMOC pastes with citric acid. The results demonstrated that citric acid as an additive of TDMOC can decrease the hydration heat release and increase the compressive strength and flexural strength of TDMOC. The possible mechanism for the strength enhancement was discussed.

Novel neuroprotective and hepatoprorective effects of citric acid in acute malathion intoxication

Objective: To study the effect of citric acid given alone or combined with atropine on brain oxidative stress, neuronal injury, liver damage, and DNA damage of peripheral blood lymphocytes induced in the rat by acute malathion exposure. Methods: Rats were received intraperitoneal(i.p.) injection of malathion 150 mg/kg along with citric acid(200 or 400 mg/kg, orally), atropine(1 mg/kg, i.p.) or citric acid 200 mg/kg+atropine 1 mg/kg and euthanized 4 h later. Results: Malathion resulted in increased lipid peroxidation(malondialdehyde) and nitric oxide concentrations accompanied with a decrease in brain reduced glutathione, glutathione peroxidase(GPx) activity, total antioxidant capacity(TAC) and glucose concentrations. Paraoxonase-1, acetylcholinesterase(ACh E) and butyrylcholinesterase activities decreased in brain as well. Liver aspartate aminotransferase and alanine aminotransferase activities were raised. The Comet assay showed increased DNA damage of peripheral blood lymphocytes. Histological damage and increased expression of inducible nitric oxide synthase(i NOS) were observed in brain and liver. Citric acid resulted in decreased brain lipid peroxidation and nitric oxide. Meanwhile, glutathione, GPx activity, TAC capacity and brain glucose level increased. Brain ACh E increased but PON1 and butyrylcholinesterase activities decreased by citric acid. Liver enzymes, the percentage of damaged blood lymphocytes, histopathological alterations and i NOS expression in brain and liver was decreased by citric acid. Meanwhile, rats treated with atropine showed decreased brain MDA, nitrite but increased GPx activity, TAC, ACh E and glucose. The drug also decreased DNA damage of peripheral blood lymphocytes, histopathological alterations and i NOS expression in brain and liver. Conclusions: The study demonstrates a beneficial effect for citric acid upon brain oxidative stress, neuronal injury, liver and DNA damage due to acute malathion exposure.

Preparation and Performance of Chitosan/Citric Acid Modified Magnesium Oxychloride Cement

Citric acid(CA)and chitosan(CS)were employed to modify magnesium oxychloride cement(MOC).Multiscale measurements were implemented to study the properties of the modified MOC pastes.Results show that the addition of CA/CS significantly changes the content of each phase and the microstructure of phase 5.The single addition of CA can effectively increase the compressive strength of MOC after 7 d curing,while CS exerts no obvious effect on the compressive strength.As to the simultaneous addition of CA and CS,the compressive strength of MOC gradually decreases with the increasing content of CS.Interestingly,mixing CA and CS significantly enhances the water resistance of MOC and decreases the degradation rate of MOC in phosphate buffered solution,which can be ascribed to the low specific surface area of the plate-like crystals in the modified MOC and the reduction of pores in the structure.

Effect of Storage Conditions on the Sensory Quality, Colour and Texture of Fresh-Cut Minimally Processed Cabbage with the Addition of Ascorbic Acid, Citric Acid and Calcium Chloride

The aim of this study was to investigate the effect of storage conditions on the sensory quality, colour and texture of fresh-cut cabbage during the addition of ascorbic acid, citric acid and calcium chloride. Ascorbic acid maintained the overall quality for 14 days at 0℃ and 7 days at 5℃;no difference, however, was observed regarding browning of cut surface compared to the control sample at both storage temperatures. Calcium chloride maintained the overall quality and cut surface browning for 14 days at both storage temperatures. It was also found that citric acid 1% can be used for minimally processed cabbage. Soaking with citric acid helped retain the color and increased the overall acceptance and organoleptic quality of fresh cut cabbage;it reduced browning of the cut surface and protected against formation of black specks. Citric acid treatment combined with low temperature storage (0℃) prolonged the shelf life of minimally processed cabbage for 22 days, time sufficient for acceptable marketing of the product. The lightness of minimally processed cabbage decreased linearly from 70.94 ± 6 to 63.8 ± 8.5 - 61.3 ± 8 units for the chemical treatments during 22 days of storage at 0℃. Hue angle values during storage time were also significantly influenced by chemical treatments mainly at 0℃.

MUF Resins Improved by Citric Acid as Adhesives for Wood Veneer Panels

This article presents the first applied results of using citric acid in combinations with a melamine-urea-formal-dehyde(MUF)resin for bonding wood veneers.The chemical reactions involved are shown based on a MALDI ToF analysis of the reaction of the MUF resin with citric acid.The preliminary results of the physical and mechanical properties of the LVL prepared are also presented.Veneers from Populus sp were used to manufacture 5-layer laminated veneer lumber(LVL)of small dimensions.Five combinations of the amount of citric acid,MUF spread rate and pressing parameters were tested.LVL bonded with 20%of citric acid+100 g/m^(2)of MUF,hot-pressed using a 3-step process with maximum 1.5 MPa of pressure yielded the board with better dimensional stability and mechanical properties.It could be concluded that citric acid in combination with MUF can be used for bonding wood veneer and the research should be continued to study further the parameters involved and to enhance the results.

Influence of pre-treatment in citric acid solution on physical and mechanical properties of thermally compressed oil palm board

Oil palm trunk is an excellent raw material for thermally compressed wood board.However,improvements to dimensional stability during water absorption and reduced thickness swelling has been tied to losses in other mechanical properties,especially as the compression temperature is increased.Toward solving this trade-off,we analyzed the effects of a 48 h pre-soak in citric acid solutions(0,5,15,25,or 35%w/v in distilled water)on the physical and mechanical properties of oil palm board compressed at 140℃.The reference benchmark case was compressed at 200℃without pretreatment.The oil palm board raw materials were obtained from outer,middle and inner parts of trunk.The results showed that the oven-dry density of compressed oil palm board made from different parts of trunk increased with thermal compression(maximum pressure 12.26 MPa for 8 min).The citric acid pretreatment improved water absorption and thickness swelling properties of oil palm board thermally compressed at 140℃,consistent with the citric acid concentration.The carboxyl groups in citric acid cross-link with the hydroxyl groups in the wood.However,no significant difference was found between the benchmark(200℃)and pretreatments with 5 or 15%citric acid.The citric acid altered the wood chemistry during hot compressing at 140℃.Static bending strength,modulus of rupture(MOR),and modulus of elasticity(MOE)slightly decreased with the citric acid pretreatment,matching the effects of high temperature compression at 200℃.

Comparative Effect of Adding Synthetic Citric Acid to Natural Lemon Juice (Citrus aurantiifolia) on the Stability of Hibiscus Drinks Stored at 4°C and 37°C

The general objective of the work is to compare the effect of the addition of synthetic citric acid compared to the addition of natural fruit juice of Citrus aurantiifolia on the conservation of drink based on red chalice H. sabdariffa. The tests were carried out over a period of 5 weeks at 4°C and 37°C with seven batches of beverage samples prepared at the rate of a calyx/water ratio of 1/40 (kg·kg-1) and added respectively citric acid at 1, 2 and 4 g·L-1 and lemon juice at 10, 20 and 40 mL·L-1. The characterization of the different batches of beverages was carried out from day one. A follow-up of the residual anthocyanin content and the intensity of the red coloring were carried out over five weeks. The anthocyanin concentration was determined by the pH-differential method. The red color degradation index is determined based on the CIELAB color system (L*, a*, b* and L*). R and Minitab 18 software was used for data processing. The results of the monitoring of the parameters showed that the concentration of 1 g AC L-1 retains 2.7 mg more of the anthocyanins than adding 10 mL JC L-1 and longer maintains red color when stored at 4°C and 37°C/5 weeks. The 2 g AC L-1 and 4 g AC L-1 ratios have the same effects as the addition of 20 and 40 mL of lemon juice, all accelerating the degradation of anthocyanins and the red color. After 5 weeks of storage at 37°C, the effect of the temperature combined with the increase in the acidity of the samples (2 to 4 g AC L-1 and 20 to 40 ml JC L-1), have accelerated the total disappearance of the red color on all samples.

CRISPR-Cas系统在病原核酸检测中的研究进展

CRISPR-Cas系统作为原核生物获得性免疫系统,由簇状规则间隔短回文重复序列(clustered regularly interspaced short palindromic repeats,CRISPR)和CRISPR相关蛋白(CRISPR-associated proteins,Cas)构成,因其识别和切割特定DNA或RNA序列,而成为分子诊断领域研究的热点。研究人员利用Cas蛋白(Cas12、Cas13、Cas14、Cas3等)结合信号放大和转化技术(荧光法、电位法、比色法、侧向流动技术等),开发了许多高灵敏度、高特异性、低成本的诊断平台,为病原核酸检测提供了新途径。本文介绍了CRISPR-Cas系统的生物学机制及分类,总结现有的基于Cas蛋白反式切割活性开发的病原核酸检测技术,描述其特点、功能和应用场景,并对该系统的未来应用前景进行展望,期望CRISPR-Cas系统成为包括核酸检测在内的多靶标的理想检测平台。

Novel Ni/CeO_2-Al_2O_3 composite catalysts synthesized by one-step citric acid complex and their performance in catalytic partial oxidation of methane

A series of novel Ni/CeOe-Al2O3 composite catalysts were synthesized by one-step citric acid complex method, The as-synthesized catalysts were characterized by N2 physical adsorption/desorption, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR） spectroscopy, hydrogen temperature-programmed reduction （Hz-TPR）, X-ray photoelectron spectroscopy （XPS） and thermogravimetry analysis （TGA）. The effects of nickel content, calcination and reaction temperatures, gas hourly space velocity （GHSV） and inert gas dilution of N2 on their performance of catalytic partial oxidation of methane （CPOM） were investigated. Catalytic activity test results show that the highest methane conversion （〉85%）, the best selectivities to carbon monoxide （〉87%） and to hydrogen （〉95%）, the excellent stability and perfect Hz/CO ratio （2.0） can be obtained over Ni/CeO2-Al2O3 with 8 wt% Ni content calcined at 700 ℃ under the reaction condition of 750 ℃, CH4/O2 ratio of 2 ： 1 and gas hourly space velocity of 12000 mL.h-1 .g-1. Characterization results show that the good catalytic performance of this composite catalyst can be contributed to its large specific surface area （~108 m2.g-1）, small crystallite size, easy reducibility and low coking rate.

Development of Better-Quality Assay Method for the Citric Acid and Sodium Citrate in Ophthalmic/Oral Solutions and Their Application to Deformulation Studies

There were several techniques determined for the analysis of citrate and citric acid mixtures in the pharmaceutical dosage forms. Titration methods, photometric and ion chromatographic methods were used for their determination. These methods will restrict too many factors where the accurate quantification of citrate and citric acid is extremely challenging. Citric acid is the natural flavor used as a preservative for many pharmaceutical applications. Deformulation techniques used for the manufacturing of generic drugs require authentic data for their regulatory submissions. Simple accurate and reproducible validated method developed for the determination of citric acid and sodium citrate by titration followed by HPLC analysis. Free citric acid was determined by the titration method and total citric acid was determined by HPLC analysis. After subtracting the free citric acid from total citric acid content, citric acid present in the sodium citrate content was determined. Sodium citrate content was determined by applying sodium correction factor to the subtracted value of the citric acid. The results met all the validation parameters and the method was successfully measured the amount of citric acid and sodium citrate in the marketed ophthalmic/oral solutions.

盐碱胁迫下苹果矮化砧木M9-T337对外源柠檬酸(CA)的响应

【目的】探究不同浓度外源柠檬酸(CA)对盐碱胁迫下苹果(砧木)幼苗生理特性的影响。【方法】以1年生苹果砧木M9-T337为试材,采用盆栽试验法,设置清水浇灌(CK1)、盐碱胁迫(CK2)、盐碱胁迫+0.2 mmol·L^(-1)CA(T1)、盐碱胁迫+0.6 mmol·L^(-1)CA(T2)、盐碱胁迫+1.0 mmol·L^(-1)CA(T3)、盐碱胁迫+1.4 mmol·L^(-1)CA(T4)6个处理,测定各处理叶片的光合荧光参数、叶绿素含量、根系形态、相对电导率(REC)、Na^(+)含量、K^(+)含量、抗氧化酶活性和渗透调节物质含量,并结合主成分分析对结果进行综合分析。【结果】喷施不同浓度柠檬酸可有效降低盐碱胁迫下M9-T337叶片电导率(REC)、胞间二氧化碳浓度(C_(i))以及Na^(+)含量的升高幅度,显著降低叶片相对含水量(RWC)、根系活力、根鲜质量比、叶绿素a(Chl a)含量、叶绿素b(Chl b)含量、叶绿素a+b(Chla+b)含量、净光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(T_(r))、初始荧光(F_(0))、最大荧光(F_(m))、光化学淬灭系数(qP)、非调节性能量耗散Y(NO)、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性与过氧化物酶(POD)活性的下降幅度,以及显著增加脯氨酸(Pro)含量,并在T3处理下达到峰值;根据主成分得分排名可知,外源CA对M9-T337盐碱胁迫缓解能力由高到低为:CK1>T3>T2>T4>T1>CK2。【结论】1.0 mmol·L^(-1)的外源CA可更好地增强盐碱胁迫下M9-T337的光合能力,提高抗氧化酶活性,增强生物膜的稳定性以及促进Na^(+)外排、K^(+)区隔化和抑制K~+外排,从而起到缓解盐碱胁迫的作用。

Production of Citric Acid from Corncobs with Its Biological Evaluation

Corncobs could serve as a substrate for citric acid production using solid state fermentation technique. The culture optimization concerning substrate concentration, culture duration, pH, temperature and substrate hydrolysis was carried out for maximum productivity of citric acid. Under the optimized conditions, 48.4 g of citric acid was produced from 1 kg dry corncobs. Biological evaluation was carried out for citric acid such as melanin synthesis inhibitory, anti-allergy, anti-bacterial, and hyaluronic acid production activities. The results showed that citric acid has potent melanin inhibitory activity, good inhibition for β-hexosaminidase release and potent stimulatory effect for the production of hyaluronic acid. These activities (melanin synthesis inhibitory, anti-allergy and hyaluronic acid productive activities) of citric acid have been reported for the first time.

黄腐酸对Ca(NO_(3))_(2)胁迫下菜薹幼苗生长及生理生化特性的影响

土壤次生盐渍化会严重影响菜薹的产量及品质,黄腐酸作为一种全水溶性的有机物质,对缓解植物盐胁迫具有积极作用。本研究以金秋红二号红菜薹为试验材料,探究在Ca(NO_(3))_(2)胁迫下外源施用黄腐酸对菜薹幼苗生长发育和生理生化指标的影响。结果表明,与15 mmol/L Ca(NO_(3))_(2)(CK)相比,80 mmol/L Ca(NO_(3))_(2)处理显著抑制了菜薹的生长,而与80 mmol/L Ca(NO_(3))_(2)处理相比,80 mmol/L Ca(NO_(3))_(2)+100μmol/L黄腐酸处理可以显著缓解Ca(NO_(3))_(2)对菜薹的抑制作用,促进菜薹幼苗的生长,增加菜薹幼苗的净光合速率及气孔导度。同时与80 mmol/L Ca(NO_(3))_(2)处理相比,80 mmol/L Ca(NO_(3))_(2)+100μmol/L黄腐酸处理可以显著降低菜薹幼苗叶片相对电导率和丙二醛含量,减少O_(2)·^(-)、H_(2)O_(2)的积累,增强抗氧化酶(超氧化物歧化酶、过氧化氢酶、抗坏血酸酶)活性。上述结果表明,外源施用黄腐酸可以通过提高菜薹的光合和抗氧化能力来缓解Ca(NO_(3))_(2)胁迫,本研究结果可为黄腐酸在缓解蔬菜盐胁迫中的应用提供理论依据。