荔枝(Litchichinensis Sonn.)花芽分化过程的细胞超微结构观察

应用透射电镜对荔枝茎尖生长锥由营养生长转变为生殖生长过程的细胞超微结构进行观察 ,结果表明 ,荔枝圆锥花序发育前期细胞排列紧密 ,细胞质浓 ,液泡小 ,细胞核大并占据着细胞大部分位置 ;细胞质内有丰富的线粒体和膜状系统 ,整个膜状系统内连细胞核 ,外接胞间连丝 ;细胞内囊泡大量形成、融合与迁移 .这些均显示出细胞内结构物质在此期经历着活跃的周转和合成代谢 ,细胞内部在基因的控制下有序地表达 ,为发育过程质的转变积累足够的信息和物质 .生长锥由尖长变为宽平的花序原基时 ,其组织细胞结构也发生了相应的变化 ,最显著的特征是在此过程中 ,有一些细胞发生了程序性死亡 .正在凋亡的细胞核染色质固缩、趋边、核膜破裂或皱缩、细胞质囊泡化并将降解的物质运到周围细胞 。

Construction of high-density SNP genetic maps and QTL mapping for dwarf-related traits in Litchi chinensis Sonn

Litchi chinensis Sonn is widely cultivated in subtropical regions and has an important economic value.A high-density genetic map is a valuable tool for mapping quantitative trait loci(QTL)and marker-assisted breeding programs.In this study,a single nucleotide polymorphism(SNP)-based high-density linkage map was constructed by a genotyping-by-sequencing(GBS)protocol using an F1 population of 178 progenies between two commercial litchi cultivars,‘Ziniangxi’(dwarf)and‘Feizixiao’(vigorous).The genetic map consisted of 3027 SNP markers with a total length of 1711.97 cM in 15 linkage groups(LGs)and an average marker distance of 0.57 cM.Based on this high-density linkage map and three years of phenotyping,a total of 37 QTLs were detected for eight dwarf-related traits,including length of new branch(LNB),diameter of new branch(DNB),length of common petiole(LCP),diameter of common petiole(DCP),length of internode(LI),length of single leaf(LSL),width of single leaf(WSL),and plant height(PH).These QTLs could explain 8.0 to 14.7%(mean=9.7%)of the phenotypic variation.Among them,several QTL clusters were observed,particularly on LG04 and LG11,which might show enrichment for genes regulating the dwarf-related traits in litchi.There were 126 candidate genes identified within the QTL regions,55 of which are differentially expressed genes by RNA-seq analysis between‘Ziniangxi’and‘Feizixiao’.These DEGs were found to participate in the regulation of cell development,material transportation,signal transduction,and plant morphogenesis,so they might play important roles in regulating plant dwarf-related traits.The high-density genetic map and QTLs identification related to dwarf traits can provide a valuable genetic resource and a basis for marker-assisted selection and genomic studies of litchi.

Effects of saponin from the seed of Litchi chinensis Sonn on TGF-β1, FN and SOCS-1 in renal tubular epithelial cells under high glucose

Objective:To investigate the effect of saponin from the seed of Litchi chinensis Sonn(SLS)on the growth and apoptosis of human kidney epithelial cells(HKC)cultured in high glucose.Methods:HKC were cultured in DMEM/F12 medium supplemented with 30 mmol/L glucose and treated with or without SLS.In the normal group,isometric DMEM/F12 medium with 5.5mmol/L glucose was added.The secretion of TGF-β1 and fibronectin(FN)were detected by ELISA.Cell apoptosis was detected by the method of Annexin V-FITC/PI double staining.Western blot was used to detect the level of suppressor of cytokine signaling-1(SOCS-1).Results:The result of ELISA showed that the secretion of TGF-β1 and FN was decreased in SLS groups compared with those in 30 mmol/L glucose treated group(P<0.05).There were more cells apoptosis in 30 mmol/L glucose treated group than that in the normal group(P<0.01).Compared with the 30 mmol/L glucose treated group,the apoptosis of HKC were significantly decreased in SLS groups(P<0.01).Western blot showed that the level of SOCS-1 in high glucose+SLS group was decreased(P<0.01),compared with the high glucose group.Conclusion:SLS can reduce the secretion of TGF-β1 and FN in HKC by reducing the deposition of extracellular matrix.SLS also significantly reduced the apoptosis of HKC by inhibiting the level of SOCS-1.These results suggest the roles of SLS in preventing the progress of glomerular sclerosis.

Expression of SAMDC Gene for Enhancing the Shelf Life for Improvement of Fruit Quality Using Biotechnological Approaches into Litchi (Litchi chinensis Sonn.) Cultivars

Polyamines play an important role in plant response to abiotic stress. S-adenosyl-1-methionine decarboxylase (SAMDC) is one of the key regulatory enzymes in the biosynthesis of polyamines. In order to better understand the effect of regulation of polyamine biosynthesis on the shelf life improvement of litchi fruit, SAMDC cDNA isolated from Datura stramonium cloned in pBI121 was introduced into litchi genome by means of Agrobacterium tumefaciens through zygote disc transformation. Transgene and its expression are confirmed by Southern and Northern blot analyses, respectively. Transgenic plants expressing Datura SAMDC produced 1.7- to 2.4-fold higher levels of spermidine and spermine than wildtype plants under normal environmental condition, which indicated that the transgenic litchi presented an enhanced polyamines synthesis compared to wildtype plants. Our results demonstrated clearly that increasing polyamine biosynthesis in plants may be a means of creating improved fruit shelf life germplasm.

荔枝(Litchi chinensis)细胞培养的初步研究

用荔枝无菌苗作为外植体，在添加了ＡｇＮＯ３或蜂王浆的含１ｍｇ／Ｌ６－ＢＡ和１ｍｇ２，４－Ｄ的ＭＳ培养基中诱导出愈伤组织，在同样培养基中继代培养，得到了稳定的培养细胞系．这种细胞在含１ｍｇ／Ｌ６－ＢＡ＋２ｍｇ／Ｌ２，４－Ｄ的ＭＳ培养基中悬浮培养，培养周期２５ｄ．结果表明：维生素Ｃ和ＮａＣｌ在悬浮培养中有良好的防褐作用．

Agrobacterium tumefaciens-mediated transformation of embryogenic callus and CRISPR/Cas9-mediated genome editing in‘Feizixiao'litchi

Litchi(Litchi chinensis Sonn.)is a type of commercially prevalent subtropical and tropical fruit.Since litchi has a highly heterozygous genetic background and a long reproductive cycle,conventional breeding methods(such as hybridization)have limited ability to nurture new litchi cultivars.Here,an efficient and stable Agrobacterium tumefaciens-mediated genetic transformation of embryogenic callus was established in‘Feizixiao’litchi.Transgenic materials were verified using polymerase chain reaction(PCR)analysis,β-glucuronidase(GUS)assay,and green fluorescent protein(GFP)assay.To implement the technology of the Clustered Regularly Interspaced Short Palindromic Repeats(CRISPR)/associated protein 9(CRISPR/Cas9)technology in‘Feizixiao’litchi and verify the validity of these transformation systems,the litchi polyphenol oxidase gene(LcPPO,JF926153)was knocked out.Various categories of mutations,covering base insertions,deletions,and substitutions,were found in transgenic materials via sequence analysis.The transformation system achieved high feasibility and efficiency,and the system of CRISPR/Cas9 was successfully employed to edit genes in‘Feizixiao’litchi.This work provides an essential foundation for investigating the functions of genes and accelerating litchi genetic improvement.

Cloning and Sequence Analysis of Expansin Genes from Litchi chinensis Fruit

Using PCR degenerate primers, designed with reference to the sequences of the conserved amino acids of known expansins, to amplify cDNA fragments in litchi fruit by RT-PCR, two different cDNA fragments , named as Lc-Exp1 and Lc-Exp2 , were cloned. Lc-Exp1 and Lc-Exp2 was respectively composed of 531 bp encoding 177 amino acids and 537 bp encoding 179 amino acids. Eight cysteine residues and three tryp-tophan residues, which is supposed to be the characteristics of expansins, are conserved in both Lc-Exp1 and c-Exp2. In addition, the homology between the two expansins is 71. 6% at nucleotide acid sequences and 76.3% at amino acid sequences. The homology of Lc-Exp1 with Fa-Exp2 or Pp-Exp1 was 92.7% or 92.1%, but that of Lc-Exp2 with Fa-Exp2 or Pp-Exp1 was only 77. 4% or 76.3% at amino acid sequences.

Molecular cloning,characterization and expression profile of the sucrose synthase gene family in Litchi chinensis

Sucrose synthase(SUS,EC 2.4.1.13)is widely considered as a key enzyme involved in plant sucrose metabolism,and the gene family encoding different SUS isozymes has been identified and characterized in several plant species.However,to date scant information about the SUS genes is available in Litchi chinensis Sonn.Here,we identified five SUS genes in litchi.These Lc SUSs shared high levels of similarity in both nucleotide and amino acid sequences.Their gene structure,phylogenetic relationships,and expression profiles were characterized.Gene structure analysis indicated that the Lc SUSs have similar exon-intron structures.Phylogenetic analysis revealed that the five members could be classified into three groups(LcSUS1 and LcSUS2 in SUSⅡ,LcSUS4 and LcSUS5 in SUSⅢ,and LcSUS3 in SUSⅠ),demonstrating evolutionary conservation in the SUS family across litchi and other plant species.The expression levels of Lc SUSs were investigated via real-time PCR in various tissues and different developmental stages of aril.For tissues and organs,Lc SUSs exhibited distinct but partially redundant expression profiles in litchi,being predominantly expressed in young leaves(sink).During aril development,the expression pattern of LcSUS1 was consistent with the trend of sugar accumulation,indicating it may play important roles in determination of sink strength in aril.Moreover,transcript levels of LcSUS2,LcSUS4,and LcSUS5 varied between cultivars with different hexose/sucrose ratios,which may regulate the sugar composition in aril.Our results provide insights into physiological functions of SUS genes in litchi,especially roles in regulating sugar accumulation in aril.

Synthesis of silver and gold nanoparticles from leaf of Litchi chinensis and its biological activities

Objective: To synthesize and isolate silver and gold nanoparticles from Litchi chinensis leaf methanolic extract, and to evaluate its comparative biological activities including muscles relaxant, analgesic, anti-inflammatory and antidiarrheal. Methods: The gold and silver nanoparticles were synthesized by dissolving methanolic extract in gold chloride and silver nitrate solution separately which were confirmed by colour change and UV-Vis spectroscopy, and pellets were collected through centrifugation. Biological activities of the extract were conducted on BALB/c mice through various standard methods and the data were subjected to One-way ANOVA. Results: The colorless gold chloride solution changed to purple soon after the addition of plant extract, demonstrating that the reaction took place and gold ions were reduced to gold nanoparticles, while colorless silver nitrate solution changed to light and dark brown that was indicative of silver nanoparticles. The muscles relaxant activity showed that silver nanoparticles were more effective than gold nanoparticles and methanolic extract in traction test. The analgesic activity showed that silver and gold nanoparticles showed highest percentage decrease in acetic acid induced writhing at the doses of 50, 100 and 150 mg/kg b.w. The highest anti-inflammatory activity was produced by gold nanoparticles followed by silver nanoparticles, while low activity was observed in methanolic leaf extract. Only the crude methanolic extract showed significant antidiarrheal activity as compared to the standard drug atropine sulphate, while antidiarrheal activities of gold and silver nanoparticles were non-significant. Conclusions: The present work concludes that isolated silver and gold nanoparticles from leaf methanolic extract shows strong muscles relaxant, analgesic and anti-inflammatory activities while crude methanolic extract possesses good antidiarrheal activity.

Study on Improving Litchi chinensis Production in Adverse Weather

Being sensitive to climatic conditions,the growth of Litchi chinensis（ lychee） can be greatly affected both in rainy warm winter which is conductive to winter shoot elongation,seriously affecting the formation of flower buds,and in rainy spring or cold late spring when lychee is flowering,seriously affecting pollination and fruit set. Thus,meteorological conditions play a decisive role in determining the distribution,growth and development,yield formation and quality of lychee. Based on meteorological conditions,some measures can be taken to reduce the impacts of adverse weather and take advantage of favorable weather conditions for the stable and high production of lychee. Therefore,the yield of lychee could be increased by improving the accuracy of weather forecasts and long-term cultivation and management techniques.

Physiological Changes during the Process of Pericarp Browning in the Postharvest Litchi

[Objective] Pericarp browning in the postharvest litchi significantly reduced its commercial value and limited the expanding of litchi markets. Physiological changes during the process of pericarp browning were determined in order to identify the underlying mechanisms. [Method] Matured Feizixiao fruits were stored at 25 ℃ and 70%±5% relative humidity. The physiological changes happened in pericarp during storage were tested at an 8-hour interval. [Result] The fruit of Feizixiao (Litchi chinensis Sonn. cv Feizixiao) turned completely brown within 72 h after being harvested under the experimental conditions. Sharp increase of the browning index occurred from 48 to 64 hours after harvest (HAH). With the browning of pericarp,water content of the whole fruit and pericarp decreased continuingly. In contrast,there were no significant changes in the water content of pulp during the same period. MDA content,pH value and relative leakage rate of pericarp were increased during storage. Most of pigment contents including anthocyanin,flavonoid,phenols,chlorophyll a and total chlorophyll decreased. POD activity was initially increased in 32 HAH and then decreased afterwards. PPO activity was decreased continuously,while the activities of catalase and superoxide dismutase exhibited the pattern of 'increasing-decreasing-increasing' as the storage time progressed. Correlation,stepwise regression and path analyses showed that water loss of pericarp was the major factor of pericarp browning. Principal and cluster analyses showed that there were two stages of pericarp browning during the course of litchi storage. [Conclusion] Water status of pericarp was the most important factor affecting pericarp browning. The pericarp browning happened by stages,which was mainly determined by the water loss of pericarp.

Effects of simulated acid rain on fertility of litchi

The regulatory role of calcium in fertility of pollen and pistil under simulated acid rain was investigated. The germination percentage of pollen treated with acid rain of pH 4.5 was 9.42% lower than that of control, and that of pH 3.5, pH 2.5 and pH 1.5 were 22.47%, 45.49% and 71.62%, respectively. Simultaneously, the injury character of pollen was obviously observed when flowers were treated with acid rain of pH 3.5. The difference in fruit setting rate between the female flower treated with acid rain of pH 4.0 and the control was significant at p 〈 0.05. Ca（NO3 ）5 of 0.2-0.4 mmol/L could promote pollen germination under the stress of acid rain. The beneficial function was reduced when calcium concentration surpassed 0.8 mmol/L. Spraying 2 mmol/L Ca（NO3 ）5 reduced the injury of acid rain to pistil and increased fruit-setting rate significantly. The physiological importance of calcium during pollen germination and pistil development was also discussed.

多胺对荔枝胚性愈伤组织增殖与体胚发生的影响

为探讨外源多胺(PAs)对荔枝胚性愈伤组织(EC)增殖及体胚发生的影响机制,该研究以“妃子笑”荔枝EC为材料,采用单因素法在增殖培养基中添加腐胺(Put)、亚精胺(Spd)及精胺(Spm),分析了不同PAs处理后EC的形态、结构、内源PAs含量及相关酶指标的变化。结果表明:(1)外源Put、Spd和Spm处理均显著提高了EC增殖率,减少了体胚诱导及萌发数量。经外源PAs处理增殖的EC胚性细胞大小较一致,染色深且均匀,多细胞原胚减少,可见已经分化完全的早期子叶胚。(2)外源PAs处理均显著提高了EC中内源PAs含量,其中Put处理的EC中各类内源PAs及总PAs含量最高;当在含外源PAs培养基上增殖的EC转入不含外源PAs的培养基上增殖时(恢复培养),EC中的Put含量仍然显著高于对照,内源Spd和Spm则显著降低。(3)外源Put处理显著提高了EC中的鸟氨酸脱羧酶(ODC)、精氨酸脱羧酶(ADC)和二胺氧化酶(DAO)活性,而外源Spd、Spm处理显著降低了EC中的ODC及ADC活性,外源Spd显著提高了多胺氧化酶(PAO)活性;恢复培养后,EC中ADC和DAO活性比恢复培养前显著降低,ODC和PAO无显著性差异。综上认为,外源PAs可以通过调节PAs代谢相关酶活性影响内源PAs含量,进而影响荔枝EC增殖和体胚诱导。该研究结果为进一步研究PAs调节荔枝体胚发生机制及提高荔枝离体再生效率提供了基础。

荔枝VQ基因家族鉴定及其对非生物胁迫的响应

【目的】VQ蛋白是一类含有保守VQ基序(FxxhVQxhTG)的植物特异性蛋白,在植物生长发育和非生物胁迫应答中发挥重要作用。研究鉴定了荔枝VQ基因家族,并分析其在不同组织的表达模式及在低温、高温、干旱和盐胁迫下的应答,为后续研究其抗逆机制奠定了基础。【方法】用生物信息学方法在荔枝全基因组中鉴定LcVQ基因,并对其理化性质、亚细胞定位、基因结构和保守基序等进行分析;用MEGA 6.0软件构建系统发育树,分析荔枝、拟南芥和水稻VQ蛋白的系统发育关系;用实时荧光定量PCR(qRT-PCR)技术验证LcVQs对多种非生物胁迫的响应情况。【结果】荔枝中共鉴定获得可聚类为9个亚族的18个VQ基因(LcVQ1-18),依次分布在荔枝的11条染色体上,其编码蛋白的氨基酸数介于111~427之间,分子质量为12.48~45.49 kD;除LcVQ15和LcVQ17定位于细胞质之外,其余LcVQ蛋白均定位于细胞核。LcVQs启动子区域包含大量植物生长发育响应元件、激素响应元件及逆境响应元件。LcVQs的表达量在不同组织中具有明显差异,总体上分为普遍性表达和特异性表达。LcVQs可快速响应非生物胁迫,在低温、高温、干旱和盐胁迫处理3 h内分别有4,3,3,4个LcVQs明显上调表达。【结论】荔枝全基因组中有18个VQ家族成员,具有典型VQ保守结构域,能差异化响应多种非生物胁迫。

荔枝种子发育过程中有机营养变化与萌发的关系

对比分析“妃子笑”和“紫娘喜”2个荔枝品种种子发育过程中的种子萌发规律,研究其淀粉、可溶性糖、有机酸和氨基酸组分及含量变化,探讨种子萌发与这些有机营养成分之间的相关性。结果表明,随着果实发育成熟,“妃子笑”荔枝种子萌发率呈先上升后下降的趋势,“紫娘喜”荔枝种子萌发率持续上升;盛花后45 d开始,“紫娘喜”荔枝种子萌发率持续高于“妃子笑”。果实发育过程中,“妃子笑”和“紫娘喜”荔枝种子中总可溶性糖含量分别呈“N”和“W”形变化,两者的淀粉含量均逐渐升高;果实完全成熟时,“紫娘喜”荔枝种子中淀粉含量显著高于“妃子笑”;两者种子中总有机酸含量均持续下降,但组分不同,“妃子笑”荔枝种子中含有8种有机酸,“紫娘喜”荔枝种子多了乳酸和琥珀酸。两个品种种子均含21种氨基酸,“妃子笑”荔枝种子总氨基酸含量呈先降低后上升至稳定水平的趋势;而“紫娘喜”种子中总氨基酸含量呈先短时降低后升高再降低的变化。相关性分析表明,两个荔枝品种的种子萌发率与淀粉含量呈极显著正相关,与总有机酸含量呈极显著负相关。说明淀粉和有机酸可能是影响种子发育与萌发的主要有机营养物质。

褐毛荔果实表型性状多样性研究

【目的】对云南省的褐毛荔种质资源果实表型性状进行遗传多样性分析,为褐毛荔种质资源的评价和利用提供依据。【方法】在褐毛荔分布较多的云南省10个县调查收集褐毛荔种质资源,采集成熟果实,评价果实的16个描述性性状和8个数量性状,并对资源进行表型多样性分析、聚类分析及主成分分析。【结果】共调查收集到93份褐毛荔资源,其中1份为焦核资源。褐毛荔种质资源果实表型遗传多样性较丰富,数量性状的遗传多样性均高于描述性性状,其中多样性指数最高的是种子质量,为2.98。变异系数最高的是果皮质量,为38.36%。果实的主要特征包括:形状为歪心形,果皮颜色淡红带微黄,果肩和果顶形状多为双肩斜和钝圆;龟裂片多为平滑,裂片峰多为毛尖,缝合线不明显,果肉颜色以蜡白色为主,果肉内膜褐色为无或少,种子形状以椭圆形为主,种皮颜色以浅褐色为主,肉质多为细嫩,香味、风味和涩味以无香、酸甜、微涩为主,种子多为大核。根据果实数量性状分析将93份荔枝资源分为5类,其中第Ⅱ类的可食率最高,为62.49%,第Ⅴ类的果实最大。根据果实描述性性状可将荔枝资源分为4类,其中第Ⅳ类的果实风味较好。主成分分析结果表明,前2个主成分主要体现了果实大小、果实可食率和可溶性固形物含量,依据主成分得分,筛选出2株优异单株。【结论】褐毛荔种质资源表型多样性较为丰富,可用于荔枝新种质创制和新品种选育。

不同品种荔枝壳中原花青素的鉴定及其体外抗氧化活性研究

为筛选适合开发天然抗氧化产品的荔枝优良品种,本研究对7个不同品种荔枝壳中总酚、总原花青素、总黄酮含量及A型低聚原花青素组分进行了分析,采用DPPH、ABTS+自由基清除法及FRAP法测定其体外抗氧化活性。结果表明,褐毛荔果壳提取物中所含抗氧化活性成分如总酚、总原花青素、总黄酮以及总A型低聚原花青素含量均为最高。经电喷雾液质联用四级杆飞行时间质谱(HPLC-Q-TOF-MS/MS)分析鉴定,得到所含物质的一级及二级质谱。质谱结果显示荔枝壳中含有的低聚原花青素组分主要为表儿茶素、原花青素A2、原花青素A4、A型三聚体及四聚体,不同品种荔枝壳中原花青素含量具有差异性(P<0.05)。褐毛荔果壳提取物表现出较强的自由基清除活性(DPPH·:1144.60μmol Trolox/g DW,ABTS^(+)·:2905.56μmol Trolox/g DW,FRAP:868.84μmol Trolox/g DW)。经皮尔逊相关性分析,原花青素单体、二聚体、三聚体含量与抗氧化活性具有显著相关性(P<0.05)。综合分析,与其他品种相比,褐毛荔果壳提取物中A型低聚原花青素含量最高,体外抗氧化活性方面表现最佳,可作为开发天然抗氧化产品的新型潜在原料加以利用。

玉林市仙进奉荔枝高产栽培技术要点

为提升荔枝(Litchi chinensis Sonn.)果实的品质和产量,针对仙进奉荔枝在玉林市的物候期表现及果实变异的问题,主要从建园、种苗选择、秋梢培养、控梢促花、疏花保果、适时采摘、采后修剪及清园等方面描述其栽培技术要点,以期为仙进奉荔枝高质量生产提供参考。

荔枝(Litchi chinensis Sonn.)叶片白化变异体遗传和转录组分析

为了解荔枝叶片白化变异体遗传特点,本研究以白化变异体比例较高的‘玉谭蜜荔’白化变异体苗与正常苗为试验材料,测定叶片叶绿素含量,并观测叶绿体结构差异,最后通过高通量测序技术对苗期叶片进行转录组测序分析。结果表明:‘玉谭蜜荔’种子实生苗中白化变异体的比例约为8.59%;白化苗叶片色素含量极低,仅为正常苗的0.519%;叶绿体的结构松散,基粒片层结构较少或缺失。对高通量测序数据进行组装和注释,共获得Unigene 42782条,平均长度987 bp,比对到Nr、KOG、KEGG、Swiss-prot四大数据库中,超过64%的Unigene序列获得注释,差异分析表明在细胞色素合成、光系统亚基合成蛋白、采光复合物a/b结合蛋白相关序列表达显著下调。本研究为该变异体的基因定位鉴定提供了一定的遗传基因注释信息。

荔枝中3种杀虫剂的残留行为及膳食风险评估

目的建立超高效液相色谱-串联质谱法(ultra performance liquidchromatography-tandem mass spectrometry,UPLC-MS/MS)测定荔枝中3种杀虫剂(虱螨脲、除虫脲和氯虫苯甲酰胺)残留的分析方法,并研究3种杀虫剂在荔枝中的残留行为及其膳食风险评估。方法荔枝中残留的3种杀虫剂采用乙腈提取,UPLC-MS/MS检测,基质匹配外标法定量。根据残留检测结果和我国不同人群的膳食消费量评估膳食风险。结果在0.0005~0.0500mg/L范围内,峰面积和浓度呈良好线性关系,相关系数均大于0.999;虱螨脲、除虫脲和氯虫苯甲酰胺在荔枝中平均回收率范围分别为81%~97%、77%~105%和73%~102%,最大相对标准偏差为14.2%,定量限均为0.010mg/kg。结果表明,虱螨脲、除虫脲和氯虫苯甲酰胺在荔枝中半衰期分别为6.3~21.8、6.3~22.1和3.9~10.6 d。膳食风险评估表明,3种杀虫剂的膳食风险商均远小于1。结论该方法简便、准确、灵敏度高,可用于荔枝中虱螨脲、除虫脲和氯虫苯甲酰胺的残留检测。于安全间隔期(14 d)时采收的荔枝样品中,除虫脲和氯虫苯甲酰胺的最终残留量均低于我国相应的最大残留限量值(0.5mg/kg和1.0mg/kg),我国尚未制定虱螨脲在荔枝中的最大残留限量。经过风险评估,3种杀虫剂在荔枝中的残留不会对不同人群健康产生不可接受的风险。