Geographical origin identification of winter jujube(Ziziphus jujuba Dongzao')by using multi-element fingerprinting with chemometrics

Winter jujube(Ziziphus jujuba'Dongzao')is greatly appreciated by consumers for its excellent quality,but brand infringement frequently occurs in the market.Here,we first determined a total of 38 elements in 167 winter jujube samples from the main winter jujube producing areas of China by inductively coupled plasma mass spectrometer(ICP-MS).As a result,16 elements(Mg,K,Mn,Cu,Zn,Mo,Ba,Be,As,Se,Cd,Sb,Ce,Er,Tl,and Pb)exhibited significant differences in samples from different producing areas.Supervised linear discriminant analysis(LDA)and orthogonal projection to latent structures discriminant analysis(OPLS-DA)showed better performance in identifying the origin of samples than unsupervised principal component analysis(PCA).LDA and OPLS-DA had a mean identification accuracy of 87.84 and 94.64%in the testing set,respectively.By using the multilayer perceptron(MLP)and C5.0,the prediction accuracy of the models could reach 96.36 and 91.06%,respectively.Based on the above four chemometric methods,Cd,Tl,Mo and Se were selected as the main variables and principal markers for the origin identification of winter jujube.Overall,this study demonstrates that it is practical and precise to identify the origin of winter jujube through multi-element fingerprint analysis with chemometrics,and may also provide reference for establishing the origin traceability system of other fruits.

Development of a texture evaluation system for winter jujube(Ziziphus jujuba‘Dongzao’)

Winter jujube(Ziziphus jujuba‘Dongzao’)is an excellent late maturing variety of fresh-eating jujube in China.Fruit texture is an important indicator of sensory quality.To investigate the correlations among texture indices and establish an evaluation system for winter jujube texture,we used the TMS-Touch instrument to perform a texture profile analysis(TPA)on 1150 winter jujubes from three major producing areas in China.Eight indices and their best-fit distribution were obtained,including fracture(Pearson),hardness(InvGauss),adhesive force(Weibull),adhesiveness(LogLogistic),cohesiveness(LogLogistic),springiness(BetaGeneral),gumminess(InvGauss),and chewiness(InvGauss).Based on the best-fit distribution curves,each index was divided into five grades(lower,low,medium,high and higher)by the 10th,30th,70th and 90th percentiles.Among the texture indices,82%of the correlation coefficients were highly significant(P<0.01);meanwhile,chewiness was significantly(P<0.01)and positively correlated with springiness and gumminess,of which the correlation coefficients were up to 0.8692 and 0.8096,respectively.However,adhesiveness was significantly(P<0.01)and negatively related to adhesive force with a correlation coefficient of–0.7569.Among hardness,cohesiveness,springiness,gumminess,and chewiness,each index could be well fitted by a multiple linear regression with the remaining four indices,with the coefficients above 0.94 and the mean fitting error and mean prediction error lower than 10%.A comprehensive evaluation model was consequently established based on factor analysis to evaluate the texture quality of winter jujube.The results demonstrated that winter jujube with higher comprehensive scores generally exhibited higher springiness and chewiness,but had lower adhesive force and adhesiveness.We used factor analysis and clustering analysis to divide the eight studied texture into four groups(cohesive factor,adhesive-soft factor,tough-hard factor,and crispness factor),whose representative indices were springiness,adhesiveness,hardness,and fracture,respectively.Overall,this study investigated the variation in each index of winter jujube texture,explored the association among these indices,screened the representative indices,and established a texture evaluation system.The results provide a methodological basis and technical support for evaluating winter jujube texture.

Physico-chemical analysis and antimicrobial potential of Apis dorsata,Apis mellifera and Ziziphus jujube honey samples from Pakistan

Objective:To evaluale physico-chemical properties and antimicrobial potential of indigenous honey samples against different reference strains including Escherichia coli ATCC 8739.Enterobacter aerogenes ATCC 13048.Pseudomonas aeruginosa ATCC 9027.Bacillus subtilis ATCC6633.Staphylococcus aureus ATCC 25923.Salmonella typhi ATCC 14028,Klebsiella pneumonia ATCC 13883.Aspergillus niger ATCC 16404.Rhizopus oligasparus PCSIR1.Candida albicans ATCC14053 and Candida utilis ATCC 9950.Methods:By using standard methods samples were evaluated for their antimicrobial properties including additive effect of starch and non—peroxidase activity,antioxidative properties(phenol contents,flavonoid contents,1,1-diphenyl-2-pierylhydrazyl radical scavenging activity).Prior to this evaluation,complete physico-chemical properties including pH,color,ash contents,protein contents,moisture contents,hydroxymethyl furfural contents,total sugar contents,reducing sugar and non-reducing sugar contents were analyzed.Results:Relatively higher ash contents were found in the Siddar honey i.e.(0.5900±0.0336)%and small honey showed relatively higher protein contents i.e.(777.598±9.880) mg/kg.The moisture contents of tested honey samples ranged between 13.8%—16,6%,total sugar contents foam 61.672%-72.420%and non-reducing sugar contents from 1.95%—3.93%.Presences of phenolic contents indicate higher antioxidant potential of these honey samples.All bacteria showed clear inhibition zones in response to tested honey samples whereas fungi and yeast showed inhibition at higher concentrations of these honey samples.For Escherichia coli.Bacillus subtilis.Salmonella typhi.Pseudomonas aeruginosa and Aspergillus niger,overall the small honey showed the higher activity than other honey samples.Conclusion:Physico-chemical analysis of honey samples confirmed good quality of honey according to the standards set by European Union Commission and Codex Alimcntarius Commission.Evaluation of these honey samples confirms antimicrobial potential of particular types of honeys indigenous to Pakistan.

Effect of pruning intensity on soil moisture and water use efficiency in jujube(Ziziphus jujube Mill.) plantations in the hilly Loess Plateau Region, China

Jujube(Ziziphus jujube Mill.)is a traditional economic forest crop and is widely cultivated in hilly areas of the Loess Plateau,China.However,soil desiccation was discovered in jujube plantations.Pruning is recognized as a water-saving method that can reduces soil water consumption.In this study,we monitored the jujube plots with control(CK),light(C1),medium(C2)and high(C3)pruning intensities during the jujube growing period of 2012-2015 to explore the effect of pruning intensity on soil moisture and water use efficiency(WUE)of jujube plantations in the hilly Loess Plateau Region.The results showed that pruning is an effective method for soil water conservation in jujube plantations.Soil moisture increased with increasing pruning intensity during the jujube growing period of 2012-2015.C1,C2 and C3 pruning intensities increased soil water storage by 6.1-18.3,14.4-40.0 and 24.3-63.3 mm,respectively,compared to CK pruning intensity.Pruning promoted soil moisture infiltration to deeper soil layer.Soil moisture infiltrated to soil depths of 240,280 and>300 cm under C3 pruning intensity,220,260 and 260 cm under C2 pruning intensity,200,240 and 220 cm under C1 pruning intensity,and 180,200 and 160 cm under CK pruning intensity in 2013,2014 and 2015,respectively.Soil water deficit was alleviated by higher pruning intensity.In 2013-2015,soil water change was positive under C2(6.4 mm)and C3(26.8 mm)pruning intensities but negative under C1(-20.5 mm)and CK(-40.6 mm)pruning intensities.Moreover,pruning significantly improved fresh fruit yield and WUE of jujube plants.Fresh fruit yields were highest under C1 pruning intensity with the values of 6897.1-13,059.3 kg/hm^2,which were 2758.4-4712.8,385.7-1432.1 and 802.8-2331.5 kg/hm2 higher than those under CK,C2,and C3 pruning intensities during the jujube growing period of 2012-2015,respectively.However,C3 pruning intensity had the highest WUE values of 2.92-3.13 kg/m3,which were 1.6-2.0,1.1-1.2 and 1.0-1.1 times greater than those under CK,C1 and C2 pruning intensities,respectively.Therefore,C3 pruning intensity is recommended to jujube plantations for its economic and ecological benefits.These results provide an alternative strategy to mitigate soil desiccation in jujube plantations in the hilly Loess Plateau Region,which is critical for sustainable cultivation of economic forest trees in this region.

Jujube(Ziziphus jujuba Mill.(Rhamnaceae)):a review on its pharmacological properties and phytochemistry

Jujube(Ziziphus jujuba Mill.)belongs to the Rhamnaceae family.It is distributed in the tropical and subtropical regions of Europe and Asia,including India,China,Iran,Russia,and the Middle East.Jujube is a highly tolerant tree that is resistant to soil salinity and alkalinity.Jujube possesses many phytochemical components and pharmacological properties that make it a good choice for the human diet.Jujube fruit is nutritious and rich in proteins,minerals,vitamins,organic acids,and carbohydrates.It also contains phytochemical components such as polyphenols,flavonoids,terpenoids,anthocyanins,alkaloids,and carotenoids.Jujube has both nutraceutical and cosmeceutical properties.All parts of this plant possess medicinal properties.Jujube has a long history of use in traditional medicine,especially in traditional Persian medicine.It has many pharmacological properties according to traditional Persian medicine,which include anti-pruritic and tranquilizing effects for renal and bladder pain.In Chinese medicine,jujube is used to increase appetite and treat diarrhea and fatigue.This indicates that jujube has several chemical constituents and beneficially affects multiple organs and tissues.These properties include antioxidant,anti-cancer,antimicrobial,neuroprotective,cardioprotective,and hepatoprotective activities.It also has health-promoting effects,including anti-aging properties.

Influence of Soil Geochemistry to the Quality of Winter Jujube in Zhanhua

[Objective] The aim was to investigate the effects of soil geochemistry on the quality of winter jujube.[Method]Based on the data of ecological geochemical survey in lower Yellow River Basin,the relevance of the geochemistry environment in top soils and the quality of winter jujubes was analyzed.[Result]Cd,Ni and other heavy metals in the soil more obviously affected the nutrition of winter jujubes.[Conclusion]B,Mn,MgO,Cd,Zn,K2O and other elements in the root soil played an important role in the enrichment of Cr and Hg of winter jujube fruit.And the absorption of heavy metals in winter jujube root could be interfered by improving fertilization method,to reduce the enrichment of harmful elements in jujube fruit.

Primary study on respiration type of lingwu Changzao （Ziziphus. jujube Mill）

Lingwu Changzao （Ziziphus. jujube Mill） is a Ningxia local variety, it has a good table quality despite its short postharvest life. The respiration rate, the weight change of single fruit during growth development and the losing water of postharvest of fruit were studied. The results showed that the curve of fruit growth development was a double sigmoid characteristic. When the surface colour of fruit changed form jade-green to alizarin crimson, the respiration rate tended to fall during a entire growth development of fruit, which showed a fluctuation phenomenon. The respiration rate descended when the surface color changed from coloring to baby red, but after a crimson stage the respiration rate recurred to its original downtrend. With increasing of single fruit weight, phenomenon of respiration climacteric has not happened and the respiration rate curve showed a concavity characteristic at some stages. As a result, there was not a phenomenon of respiration climacteric with a double sigmoid growth development curve characteristic of fruit.

Effect of Nitric Oxide on Alcoholic Fermentation and Qualities of Chinese Winter Jujube During Storage

This article investigates the effects of nitric oxide （NO） on alcoholic fermentation and the qualities of Chinese Winter Jujube during storage, and explores the action mechanisms of browning and softening of fruits to provide theoretical proofs for using NO in the storage of Chinese Winter Jujube. Chinese Winter Jujube fruits were fumigated with different concentrations of NO gas （0, 10, 20, 30 μL L^-1） under anaerobic conditions and stored at 22±1℃ and 4± 1℃. The changes in appearance qualities, the contents of pyruvate, ethanol, acetaldehyde, and the activities of alcohol dehydrogenase （ADH） and lactate dehydrogenase （LDH） were investigated. The contents of pyruvate, ethanol, and acetaldehyde were significantly reduced, and the peak of pyruvate content was delayed by 20 μL L^-1 NO. The activities of ADH and LDH in 20 μL L^-1 NO treated fruits were also significantly inhibited. However, the alcoholic fermentation and softening of Chinese Winter Jujube fruits were promoted by 30 μL L^-1 NO during storage. The results indicated that 20 μL L^-1 NO could mitigate the injury of ethanol on Chinese Winter Jujube and effectively delay the browning and softening of fruits during storage.

The regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube

Fruit lignification is due to lignin deposition in the cell wall during cell development.However,there are few studies on the regulation of cell wall lignification and lignin biosynthesis during fruit pigmentation.In this study,we investigated the regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube.The cellulose content decreased,while the lignin content increased in the winter jujube pericarp during pigmentation.Safranin O-fast green staining showed that the cellulose content was higher in the cell wall of winter jujube prior to pigmentation,whereas the lignin in the cell wall increased after pigmentation.The thickness of the epidermal cells decreased with pericarp pigmentation.A combined metabolomics and transcriptomics analysis showed that guaiacyl-syringyl(G-S)lignin was the main lignin type in the pericarp of winter jujube,and F5H(LOC107424406)and CCR(LOC107420974)were preliminarily identified as the key genes modulating lignin biosynthesis in winter jujube.Seventeen MYB and six NAC transcription factors(TFs)with potential regulation of lignin biosynthesis were screened out based on phylogenetic analysis.Three MYB and two NAC TFs were selected as candidate genes and further studied in detail.Arabidopsis ectopic expression and winter jujube pericarp injection of the candidate genes indicated that the MYB activator(LOC107425254)and the MYB repressor(LOC107415078)control lignin biosynthesis by regulating CCR and F5H,while the NAC(LOC107435239)TF promotes F5H expression and positively regulates lignin biosynthesis.These findings revealed the lignin biosynthetic pathway and associated genes during pigmentation of winter jujube pericarp and provide a basis for further research on lignin regulation.

Study on the Antioxidation of the Compound Beverage of Winter Jujube and Peanut Meal

[ Objective] The aim was to study the antioxidative index of the compound beverage of winter jujube and peanut meal, discuss the im-pact of the storage conditions on its antioxidative activity and provide theoretical basis for the utilization of winter jujube and peanut meal resources. [Method] A kind of compound beverage was prepared with winter jujube and peanut meal, and its antioxidative activity was detected and its best storage conditions were determined. [ Result] The capacity of the compound beverage stored for 20 d to scavenge · OH, DPPH · and nitroso was the highest at freeze conditions, then followed by the refrigeration conditions, room temperature storage and sunlight. The total reducing capacity of the products was the highest under freezing conditions while the lowest under sunlight when some active components were destroyed. [ Conclusion] It is the best to store the compound beverage of winter jujube and peanut meal at freeze conditions and better at the refrigeration conditions. The storage of compound beverage should avoid direct sunlight. Key words Winter jujube; Peanut meal; Compound beverage; Antioxidation; China

Study on Detection of Pesticide Residues on Winter Jujube Surface by Near-infrared Spectroscopy Combined with PLS and SPA

With fresh winter jujube from the southern region of Xinjiang as the object of study, the method for detecting pesticide residues on winter jujube surface by near-infrared spectroscopy （NIR） combined with successive projections algorithm （SPA） and partial least squares （PLS） was investigated. The absorbance information of winter jujube sample surface was obtained through NIR technology, for the building of a full-wave band PLS model of fresh winter jujube sample sprayed with different concentrations of pesticide （taking chlorpyrifos as an example） as well as an SPA-PLS model which was built with the characteristic wavelengths extracted with SPA as the input variables for PLS, and the prediction precision of the two kinds of models was compared. The model built with the five characteristic waveslengths extected by SPA method only used the variables 0.32% of all the variables in the full wave band, but its accuracy and precision were better than the model built with the full wave band. It is feasible to build a model for different concentrations of chlorpyrifos on fresh winter jujube surfarce by NIR technology combined with SPA and PLS, and SPA method could simplify the complexity of the model and improve the precision and stablity of the model.

Occurrence and Pollution-free Control of Apolygus lucorum in Winter Jujube

In recent years, Apolygus htcorum has become the main pest of winter jujube. It sucks juice of young parts of winter jujube and causes falling of buds and flowers, leaf perforations, deformities and fall- off of fruits, leading to serious economic loss. Considering the occurrence characteristics and control problems, the distribution, occurrence regularity, damage characteristics and outbreak reasons of A. lucorum are overviewed and analyzed in this paper, and the pollution-free control measures are also put forward.

枣(Ziziphus jujuba Mill.)品种结实特性研究

对河北省沧县枣种质资源圃124个和山西果树研究所国家枣种质资源圃156个枣品种(品系)在自花授粉和自然授粉条件下的结实及种仁发育情况进行了调查。结果表明,供试品种自然授粉和自花授粉条件下的平均结实率(结果数/100枣吊)分别为37.06%、20.63%,变幅分别为4.17%～175.00%、0%～163.64%,平均可育率(含仁果实/果实总数×100%)分别为12.10%、3.07%,变幅均为0%～100%;自花结实率和自然结实率极显著正相关,相关系数0.597;供试枣品种可分成自花不实异花可实不育、自花不实异花可育、自花异花均可实不育、自花可实不育异花可育、自花异花都可育等5种结实类型,分别占总品种数的10.27%、16.06%、45.19%、17.15%、11.33%;筛选出稳定表现自花不实或自花可实不育而异花授粉可育率高且种仁饱满的品种2个(小枣4、小墩墩枣),种仁较饱满的5个(洪赵十月红、广东白枣、大荔圆枣、小枣25、圆铃枣),利用这些品种做母本进行杂交育种时可省略去雄程序,有效解决因枣花小去雄难的问题;蛤蟆枣、团枣、无核小枣、马牙枣、核桃纹等自花不实而异花可实的品种,在栽植时应配置授粉树。

Effects of IBA on the rooting of branch cuttings of Chinese jujube (Zizyphus jujuba Mill.) and changes to nutrients and endogenous hormones

‘Zhongqiusucui’ jujube secondary shoots were treated with 3-indolebutyric acid(IBA) at three concentrations, 500, 1000 and 1500 mg/L. Results show that IBA could significantly enhance rooting and root characteristics of cuttings and were best with IBA at 1500 mg/L. In the rooting process, the formation of adventitious roots was related to the consumption and accumulation of nutrients(soluble sugars and proteins) and the changes in endogenous hormones in phloem, leaf tips and leaf bases. The rooting of cuttings had a positive correlation with the consumption of soluble sugars during the period of callus formation and with the accumulation of soluble sugars during adventitious root formation and growth. Rooting was positively related to the breakdown of soluble proteins in the phloem when the callus formed, and had a positive correlation with its accumulation during adventitious root formation and growth. Leaf tips and leaf bases showed a reverse trend in changes of soluble protein. However, together with the phloem, leaf tips and leaf bases regulated and controlled the formation and development of adventitious roots. The main activities of soluble proteins exist in the leaf tips as this was the main source of soluble proteins. The relation between rooting and IAA(indole-3-acetic acid) content in phloem was positive and thus a high concentration of IAA could benefit the induction and formation of adventitious roots. However, rooting was negatively related with ABA(abscisic acid) and GA(gibberellic acid) and a high concentration of both could inhibit the induction and formation of adventitious roots. Rooting had a positive correlation with phloem IAA/ABA ratios, and higher ratios could improve rooting. Low concentrations of ZR(zeatin riboside) triggered the induction of adventitious roots, while higher concentrations promoted root growth.Endogenous hormones in leaf tips and bases had an impact on rooting. The activities of endogenous hormones mainly existed in leaf tips because they play a major role in the production and consumption of IAA and its ABA content increased during rooting. The ZR in leaf tips influenced the rooting of cuttings, especially in the callus formation and rooting stage. Leaf tips were the main source of GA.

Storage and Remobilization of Nitrogen by Chinese Jujube(Z. jujuba Mill. var. inermis Rehd) Seedling as Affected by Timing of ^(15)N Supply

Winter jujube orchard nitrogen （N） management aims at increasing N reserves to meet the tree＇s growth requirements. Fertilization strategies should maximize the efficiency of fertilizers, including the choice of the optimal timing of N supply. ^15N-urea was applied to winter jujubes on Jinsixiaozao jujubes rootstock to evaluate the effect of application timing on Nstorage and remobilization in mature trees in pot culture. The treatments consisted of ground application before budding （BB）, during fruit core-hardening stage （FCH）, and fruit rapid-swelling stage （FRS）. Nitrogen-use efficiency of treatments were significantly different, which were 2.42% （BB）, 9.77% （FCH）, and 9.01% （FRS） in the dormant and 5.20% （BB）, 16.16% （FCH）, and 10.30% （FRS） in the following full-bloom. N supply in the pre-harvest helped to increase N-reserves of trees and then translocate to the new growth organs the following year. The largest amount of ^15N was detected in the roots and trunks. In all the treatments, the partition rates were highest in coarse roots, which were 30.43% （BB）, 38.61% （FCH）, and 40.62% （FRS）, respectively. ^15N stored in roots and trunks was used by jujube trees to sustain new growth in the following full-bloom. ^15N applied before budding resulted in lower Ndff% in perennial organs （trunks and coarse roots） sampled in the following full-bloom, but fine roots had highest Ndff% （1.28%）. Other organs recovered similar amount of Ndff%. In contrast, FCH and FRS treatments led to higher Ndff% （4.01-5.15%） in the new growth organs （new growth branches, deciduous spurs, leaves and flowers）, but lower Ndff% in perennial branches （1.49-2.89%）. With the delay of ^15N-urea application time, ^15N increased the partitioning to roots. FCH treatment increased N-storage in perennial organ during winter, which should be remobilized to sustain new growth the following spring.

Effects of flue gas desulfurization gypsum and clover planting on qualities of soil and winter jujube in coastal saline-alkali orchard of north China

Flue gas desulfurization gypsum and clover planting alleviated the soil salinization stress.Soil pH and total phosphorus affected the bacterial communi-ties.Total phosphorus affected the fungal communities.Flue gas desulfurization gypsum and clover planting improved jujube quality.The coastal area of Shandong Province,characterized by coastal saline tidal soil,is one of the main production areas of winter jujube in China.However,the low soil fertility and poor soil structure in jujube orchard restricted the development of the jujube industry.The objectives of this study were to 1)evaluate the effect of application of flue gas desulfurization(FGD)gypsum and clover planting on soil quality improvement and soil microbial community structure of jujube orchard;2)investigate the effects of two measures on the nutrition and quality of winter jujube.The results showed that FGD gypsum reduced the soil total salt content by 65.6%,and clover planting increased the soil organic matter content by 30.7%,which effectively alleviated the soil salinization stress and improved the soil structure.Soil pH and total phosphorus(TP)were the main determinants influencing bacterial community composition,and TP was the dominant factor of the fungal community composition in the saline-alkali soils.Meanwhile,FGD gypsum addition and clover planting significantly increased the sugar degree and Vc content of winter jujube,thus improved jujube quality,and further contributed to the ecological sustainable development of winter jujube industry.

冬枣(Ziziphus jujube Mill.)根际3株促生细菌的筛选与鉴定

为给冬枣(Ziziphus jujube Mill.)生物肥料的研制和生产提供优良菌株资源,利用梯度稀释法和三区划线法从冬枣根际土壤中分离、纯化出832株细菌分离物,进一步通过小麦叶片保绿法和萝卜子叶增重法筛选出效果较好的3株,分别记为DZ1、DZ2和DZ3.这3株细菌分离物均不产异戊烯基腺嘌呤,其中DZ1和DZ2分泌反式玉米素(分别为368.73和598.46 ng mL-1)、激动素(273.56和193.16 ng mL-1)和吲哚乙酸[9.24和13.85μg mL–1(OD600 nm)–1],而DZ3分泌激动素(175.4 ng mL-1)和反式玉米素(314.34 ng mL-1),但不产吲哚乙酸.通过形态学观察、生理生化测定、16S rRNA基因测序及系统发育树分析,初步确定DZ1和DZ2为枯草芽孢杆菌(Bacillus subtilis),DZ3为芽孢杆菌属(Bacillus sp.).最后通过盆栽试验对这3株细菌分离物的促生效果进行比较,结果发现,DZ1、DZ2和DZ3,尤其是DZ1,对冬枣细根的生长及地上部干物质积累有积极作用,可作为研制冬枣生物肥料的优良菌株资源.

微咸水灌溉下冬枣光合生理性状与光响应模型研究

【目的】研究不同灌溉水矿化度对冬枣光合生理性状的影响。【方法】基于大田试验,研究1g/L(S1)、2 g/L(S2)、3 g/L(S3)、4 g/L(S4)和5 g/L(S5)灌溉水矿化度下的土壤水盐分布规律与冬枣光合生理响应机制。【结果】叶片净光合速率、蒸腾速率和气孔导度均在3 g/L处理或4 g/L处理下达到峰值;与其他处理相比,4 g/L处理与5g/L处理灌溉水矿化度下的叶片叶绿素量、最大荧光效率和最大量子效率显著降低;与1g/L处理相比,3 g/L处理与4 g/L处理下的冬枣表观量子效率、最大净光合速率、光补偿点、暗呼吸速率显著升高,而光饱和点显著降低,3~4 g/L灌溉水矿化度虽然减小了冬枣的可利用光强范围,但提高了叶片的生理活性。【结论】在果实膨大期,灌溉水矿化度为1~3 g/L时,气孔限制是影响冬枣光合作用的主要因素,而当灌溉水矿化度超过4 g/L时,非气孔限制因素是导致叶片光能利用效率降低的主要原因。综合考虑土壤生态环境与冬枣生理过程,推荐采用3g/L矿化度的微咸水对冬枣进行灌溉。

吡唑醚菌酯在冬枣中的残留消解及膳食风险评估

2021—2022年在河北黄骅开展了250 g/L吡唑醚菌酯乳油在冬枣中的规范残留田间试验,样品采用QuEChERS法净化,气相色谱-电子捕获检测器检测分析,得出吡唑醚菌酯在冬枣中的残留消解规律,并对其进行膳食风险评估。2年残留消解试验结果显示,吡唑醚菌酯在冬枣中的半衰期分别为9.86、11.8 d,消解规律符合一级动力学方程;最终残留试验结果显示,末次药后14~28 d,吡唑醚菌酯残留量为0.297~0.684 mg/kg,其中,末次药后21 d的残留试验中值为0.432 mg/kg。膳食风险评估得出风险商为0.62%,膳食摄入风险可接受。建议250 g/L吡唑醚菌酯乳油在冬枣上使用剂量为3000~4000倍液,每季最多施药3次,施药间隔期7 d,安全间隔期21 d。

枣种质资源果实质地品质特性分析

旨在建立标准化、统一化的枣果实质地品质鉴定评价方法,为枣种质资源质地品质精准鉴定评价提供理论参考依据。以50份枣种质脆熟全红期果实为试材,采用质构仪整果穿刺法鉴定果实质地品质,并对果实质地品质进行感官鉴定评价。结果表明,果皮穿刺强度、果皮破裂距离、果皮韧性、皮肉跌落脆性、果肉平均坚实度和果肉纤维指数6项指标在不同种质间存在丰富的多样性,变异系数为18.31%~40.40%。口感感官评价方法鉴定的果皮厚度、果肉质地和果肉粗细在不同种质间差异较大。质构仪分析得到的各项参数与感官评价参数间具有不同程度的相关性,果皮穿刺强度、果皮破裂距离、果皮韧性、果肉平均坚实度和果肉纤维指数5项指标均与感官评价的果肉质地呈极显著正相关,果肉纤维指数与感官评价的果皮厚度、果肉质地和果肉粗细间都呈极显著负相关,相关系数分别为-0.452、-0.364和-0.549。因子分析共提取两个主因子,包括果皮韧性、果肉平均坚实度和皮肉跌落脆性3项指标,累积贡献率为75.909%。基于因子分析结果,采用系统聚类法将50份供试种质分为3个类群,根据质地参数特征,分别将其定义为皮厚质密群、皮薄质疏群和中间类群。本研究建立了质构仪检测枣果质地品质的标准体系,可用于枣果实质地品质的精准鉴定评价。