杜艳民^,, 王文辉^,, 贾晓辉, 佟伟, 王阳, 张鑫楠中国农业科学院果树研究所/辽宁省果品贮藏与加工重点实验室,辽宁兴城 125100

The Effects of Different Oxygen Concentration on Postharvest Physiology and Storage Quality of Yali Pear

DU YanMin^,, WANG WenHui^,, JIA XiaoHui, TONG Wei, WANG Yang, ZHANG XinNanInstitute of Pomology, Chinese Academy of Agricultureal Sciences/Key Laboratory of Fruit Storage and Processing of Liaoning Province, Xingcheng 125100, Liaoning

通讯作者: 王文辉,E-mail： wangwenhui@caas.cn

责任编辑: 赵伶俐
收稿日期:2020-03-30接受日期:2020-06-9网络出版日期:2020-12-01

基金资助:

国家现代梨产业技术体系.CARS-28 国家自然科学基金.32001761

Received:2020-03-30Accepted:2020-06-9Online:2020-12-01
作者简介 About authors
杜艳民,E-mail： duyanmin@caas.cn。








摘要
【目的】明确环境氧气（O₂）浓度对鸭梨采后贮藏品质及生理代谢的影响,为鸭梨采后生理病害防控,延长贮藏期提供理论依据。【方法】将采自河北石家庄地区的鸭梨经缓慢降温后置于气调试验箱,设置1.0%、2.0%、3.0%、5.0%及10.0%等不同O₂浓度梯度,CO₂浓度为0.5%,以空气处理为对照,分别于贮藏150、210和270 d及货架7或10 d,调查鸭梨虎皮指数和黑心指数,测定果实硬度、可溶性固形物（SSC）、可滴定酸（TA）、抗坏血酸（AA）及色泽变化情况,利用气相色谱分析测定果肉和果心组织乙醇含量变化情况,监测果实呼吸速率和乙烯产量;利用实时荧光定量PCR对鸭梨乙烯合成关键基因PbACS和PbACO表达变化情况进行测定。【结果】低氧处理显著降低了鸭梨贮藏期间果实黑心指数和虎皮指数,贮藏270 d及货架7 d,鸭梨采后生理病害发病程度由高到低依次为：CK>10.0% O₂>5.0% O₂>1.0% O₂>3.0% O₂>2.0% O₂;同时,延缓了贮藏早期果实TA和AA下降,推迟了果实果面转黄。气调贮藏150 d,果肉和果心乙醇含量显著升高,O₂浓度与乙醇含量呈负相关,乙醇含量范围为150.89—806.12 mg?L ^-1,货架后乙醇含量下降;对照果实贮藏270 d,果实乙醇含量快速积累,衰老褐变加剧;同时,5.0%及以下O₂显著抑制了贮藏后乙烯产量,推迟了乙烯释放高峰;1.0%—3.0% O₂处理显著抑制了果皮组织中PbACO1、PbACO3及PbACS1的表达。【结论】1.0%—3.0% O₂处理更好地抑制了鸭梨采后虎皮病的发生,推迟了乙烯释放高峰,延缓了果实TA和AA下降,显著抑制了果皮组织中PbACO1、PbACO3及PbACS1表达,更好地维持了果皮亮度及白度,鸭梨贮藏期明显延长。但1.0% O₂处理在一定程度上增加了鸭梨贮藏末期黑心病风险,建议生产中鸭梨最佳O₂浓度参数为3.0%—5.0%。
关键词： 鸭梨;O₂;生理病害;品质;乙烯

Abstract
【Objective】The aim of this study was to clarify the effects of environment oxygen concentration on postharvest physiology and storage quality, affording the theory basis to prevent the postharvest disorders and prolong the storage period of Yali fruit. 【Method】Pear samples were harvested from the commercial orchard in Shijiazhuang city, Hebei province. The fruits of uniform size and ripeness without insect pests or mechanical injury were selected as research materials. The selected fruits were put into controlled atmosphere chambers, and precooling at 8℃ for 48 h, and then declined by 1℃ for every 2 days, and finally storage at (0±0.5)℃ (RH>95%). Then the controlled atmosphere (CA) was established under different O₂ concentrations (1.0%, 2.0%, 3.0%, 5.0% and 10.0%) plus 0.5% CO₂, and taking air as control. Fruit firmness (FF), soluble solids content (SSC), titratable acidity (TA), ascorbic acid (AA), ethanol, respiration rate, ethylene production and the relative expression of ethylene biosynthesis genes PbACS and PbACO were determined after the fruits storage for 150 d, 210 d and 270 d, respectively. 【Result】The heart browning incidence and superficial scald incidence were both declined significantly under CA treatments during long period storage. More specifically, after storage for 270 d and shelf-life for 7 d, the disorder prevention efficiency were followed by the order of CK>10.0% O₂>5.0% O₂>1.0% O₂>3.0% O₂>2.0% O₂. Besides that, the lower O₂ treatments maintained TA and AA contents at a higher level in the early storage period, and delayed the yellow-turning of peel; ethanol was accumulated much more under the lower O₂ concentration, which ranged from 150.89 mg?L ^-1 to 806.12 mg·L ^-1 after storage for 150 d; while with the increasing senescence browning of fruit in air, the ethanol content peaking at 1 500 mg·L ^-1 after storage for 270 d. 5.0% and lower O₂ inhibited the ethylene biosynthesis and delayed the peaking time, and 1.0%-3.0% O₂ could prohibit the relative expression of PbACO1, PbACO3 and PbACS1 genes in pericarp tissue significantly. 【Conclusion】1.0%—3.0% O₂ prohibited the superficial scald occurrence significantly, and delayed the decrease of TA and AA, inhibited the biosynthesis of ethylene and delayed the peaking time, down-regulated the relative expression of PbACO1, PbACO3 and PbACS1 genes in pericarp tissue, prolonged the storage period of Yali pear significantly. However, 1.0% oxygen treatment increased the risk of heart browning to some extent. Therefore, the optimum oxygen concentration was proposed at 3.0%-5.0% in commercial practice.
Keywords：Yali pear;oxygen;disorders;quality;ethylene


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本文引用格式
杜艳民, 王文辉, 贾晓辉, 佟伟, 王阳, 张鑫楠. 不同O₂浓度对鸭梨采后生理代谢及贮藏品质的影响[J]. 中国农业科学, 2020, 53(23): 4918-4928 doi:10.3864/j.issn.0578-1752.2020.23.016
DU YanMin, WANG WenHui, JIA XiaoHui, TONG Wei, WANG Yang, ZHANG XinNan. The Effects of Different Oxygen Concentration on Postharvest Physiology and Storage Quality of Yali Pear[J]. Scientia Agricultura Sinica, 2020, 53(23): 4918-4928 doi:10.3864/j.issn.0578-1752.2020.23.016


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0 引言

【研究意义】鸭梨（Pyrus bretschneideri Rehd.）是我国传统特色主栽梨品种,季产年销,也是我国主要仓储和出口品种^[1]。但其对低温和高浓度CO₂敏感,长期贮藏过程中极易发生虎皮病和黑心病等采后生理病害,严重影响果实商品价值,造成巨大经济损失^[2,3]。目前,我国鸭梨贮藏主要采用普通冷藏和气调贮藏两种方式,其中普通冷藏（环境温度：-1℃—0℃）一般可贮藏5—6个月（从9月至翌年3月）,气调贮藏（商业应用参数：10% O₂+1% CO₂）一般可贮藏6—8个月（从9月至翌年4月）。整体来看,与市场正常供应需求（至翌年6月）仍有较大差距^[4,5]。研究低O₂浓度对鸭梨采后生理代谢及贮藏品质的影响,对进一步延长鸭梨贮藏和货架供应期具有重要意义。【前人研究进展】气调贮藏是目前国内外商业应用最广泛的果品贮藏技术,与普通冷藏相比,气调贮藏可显著延长苹果和梨采后贮藏和货架供应期。其主要原理是在低温的基础上,通过进一步降低环境氧气含量,来进一步抑制果实采后呼吸和乙烯等生理代谢水平,降低营养损耗,延缓衰老,减轻生理病害发生,进而更好地保持果实贮藏品质^[6,7,8]。近年来,随着气体成分精准监测和控制技术的不断发展,果实气调贮藏中的O₂浓度不断降低,从传统的静态低氧气调（O₂：2.0%—5.0%）,发展到静态超低氧气调（O₂<1.5%）及前期超低氧胁迫气调（O₂：0.5%,维持2周）,一直到目前的动态气调（O₂：0.3%—0.5%）,果实贮藏期不断被延长,果实品质得到了更好的维持^[9]。但不同品种及不同栽培管理条件下,梨果实采后生物学特性及内在品质差异较大,对贮藏环境O₂敏感性及耐受度不同。研究发现,‘Beurré d’Anjou’经0.5% O₂胁迫处理后,于1.0% O₂+0.1% CO₂条件下可正常贮藏9.2个月^[10];‘Abate Fetel’在0.8% O₂+0.45% CO₂动态气调条件下可贮藏7个月,且未发生果心褐变^[11,12,13];‘Rocha’在0.5% O₂条件下贮藏8.5个月,7 d货架（20℃）后仍较好地保持果实品质,未发生黑心病^[14]。相比而言,‘Conference’一般在O₂>2.0%条件下贮藏,过低的氧气浓度会加重贮藏初期黑心病的发生^[15,16,17]。关于鸭梨气调贮藏的研究最早可追溯到20世纪90年代,研究发现采用7.0%—10.0% O₂可显著延长鸭梨贮藏期,贮藏213 d及10 d货架后（15℃）,与空气对照相比,早期和晚期黑心病发生率降低,较好地保持了梨果绿色和硬度;同时发现O₂浓度一定,黑心褐变程度随CO₂浓度升高而显著加重,生产上建议CO₂<1.0%;CO₂浓度一定,O₂下降至5.0%时,也使果心褐变程度加重^[18,19,20]。西洋梨采后气调贮藏研究发现,与果实预冷后直接开始气调相比,推迟气调贮藏建立时间可显著降低长期贮藏过程中梨果心褐变的发生^[21,22]。【本研究切入点】低氧及超低氧气调处理作为防控果实采后生理病害发生,延长果实贮藏及货架供应期的关键技术在西方梨品种上广泛应用,而关于低氧处理对我国主要白梨品种采后生理代谢及品质维持的影响鲜有研究报道。【拟解决的关键问题】明确不同O₂浓度处理下鸭梨采后生理代谢和品质变化规律,探讨其对生理病害发生的影响,初步阐明低氧防控鸭梨采后生理病害发生的作用机制。

1 材料与方法

1.1 材料与处理

本研究分别于2013—2014和2014—2015年两个贮季重复进行,并于2016—2019年在河北石家庄地区气调贮藏企业开展中试。所用鸭梨试材均于9月中旬采自河北省石家庄市商品果园,试验果于采收次日经10 h运回中国农业科学院果树研究所实验室。选取大小均匀、果面整洁、无病虫害、无机械伤的果实进行试验处理。中试果于采收当天运回中试气调库,定期跟踪调研果实生理病害发生情况及货架表现。

将挑选后的果实置于气调试验箱,每个处理均设置3个重复,每个重复处理果实约180个;8℃预冷48 h后开始阶段缓慢降温,每1 d降0.5℃,直至环境温度降至（0±0.5）℃。稳定2 d后,封口,开始进行气调贮藏（气调参数为O₂：1.0%、2.0%、3.0%、5.0%和10.0%;CO₂：0.5%）,以空气为对照,气调箱内相对湿度>95.0%。贮藏150、210及270 d后取样,分别于取样次日及货架7 d或10 d进行果实组织褐变指数调查与生理品质测定,每个处理每个重复每次取果实50个,其中15个果实用于生理病害调查和生理品质测定,9个果实用于测定呼吸速率和乙烯释放速率;另取5个果实,用水果刀于果实赤道部位取果皮组织（厚约2—3 mm）并立即用液氮速冻,-80℃超低温冰箱保存备用;剩余果实置于20℃恒温箱（SANYO,日本）模拟货架,7 d或10 d后进行生理病害调查、生理品质测定及果皮冻样。中试果9—12℃入库,35—40 d降至（0±0.5）℃,气调贮藏参数为3.0%—5.0% O₂+0.5%—0.8% CO₂。

1.2 测定指标与方法

1.2.1 虎皮指数和黑心指数 参照杜艳民等^[23]方法计算鸭梨虎皮病和黑心病发生指数,具体方法如下。

虎皮指数：按褐变面积占果皮面积的百分比,共分为5级：果皮无褐变为0 级;褐变面积≤25%为1级;25%<褐变面积≤50%为2级;50%<褐变面积≤75%为3级;褐变面积>75%为4级。虎皮指数 = [∑（虎皮级数×该级果数）/（调查总果数×4）]×100%。

黑心指数：沿果实赤道线作横切,按褐变面积占果心面积的百分比,共分为5级：果心无褐变为0级; 褐变面积≤25%为1级;25%<褐变面积≤50%为2级;50%<褐变面积≤75%为3级;褐变面积>75%为4级。黑心指数=[∑（黑心级数×该级果数）/（调查总果数×4）]×100%。

1.2.2 果皮颜色 利用CR-400色差计（MINOLTA,日本）测定果实赤道部位对称两点色泽指数,其中L*值表示果实亮度,0—100分别表示果实由暗到亮变化;b*值表示黄色和蓝色之间的变化。

1.2.3 内在品质指标测定 利用果实质构仪（GS-15,FTA2,南非）测定果实赤道部位对称两点去皮果肉硬度（探头直径11 mm）;将果实纵切后,取出果心和种子,将果肉组织匀浆过滤,分别利用数显折光仪（PR-101,ATAGO,日本）测定果实可溶性固形物含量;可滴定酸和抗坏血酸含量使用自动智能电位滴定仪（808 Titrando,瑞典）,分别用0.1 N NaOH标准液和2,6-二氯靛酚吲哚酚钠盐滴定;参考纪淑娟等^[24]的方法,采用日本岛津GC-2010气相色谱仪和Tubro Matrix×40自动顶空进样器测定乙醇含量,单位为mg·L^-1。

1.2.4 呼吸速率和乙烯产生速率 果实呼吸速率和乙烯产生速率测定均采用SP—9890气相色谱仪（山东,鲁南瑞虹仪器公司）测定,以mg CO₂?kg^-1?h^-1和μL C₂H₄?kg^-1?h^-1计,色谱参数为进样器80℃,柱炉100℃,检测器160℃,转化炉360℃。每个处理3次重复,每个重复用果9个。

1.2.5 总RNA提取与cDNA合成 根据柱式植物总RNA抽提纯化试剂盒SK8661（上海生工）说明书提取果皮组织总RNA,紫外分光光度计和1.5%琼脂糖凝胶电泳检测质量合格的总RNA采用RevertAid Premium Reverse Transcriptase （Thermo Scientific? EP0733,USA）试剂盒反转录为cDNA,作为乙烯合成与信号转导途径关键基因的表达分析。

1.2.6 乙烯合成基因表达分析 通过检索梨基因组（Pear Genome Project,http://peargenome.niau.edu.cn）,获得梨乙烯合成途径关键基因6个,特异定量引物序列参考慕茜^[25]方法（表1）,委托上海生工公司合成引物序列。参照SG Fast qPCR Master Mix（2X）（BBI）（Roche 罗氏）（B639271）说明书配置总体积为20 μL的实时荧光定量PCR反应液,包含10 μL 2×SybrGreen qPCR Master Mix、上下游引物各0.4 μL、7.2 μL ddH₂O、2 μL模板。在LightCycler480 Software Setup（Roche 罗氏）荧光定量PCR仪上进行扩增,扩增程序为：95℃预变性3 min;95℃变性7 s,57℃退火10 s,72℃延伸15 s,45个循环。PCR循环结束立即进行熔解程序。在Eppendorf的Mastercycler? ep realplex软件中自动生成标准曲线、熔解曲线和样品Ct值。每个样品重复3次。采用2^-??Ct法计算基因在各样品中的相对表达量。

Table 1
表1
表1引物序列
Table 1Primer sequences

基因名称 Gene name	基因ID Gene ID	正向引物 Forward primer sequence (5′-3′)	反向引物 Reverse primer sequence (5′-3′)
PbACO1	Pbr000093.1	GACGCTGGTGGTATCATCCT	TTCCGTCCGACTGAGCTATC
PbACO2	Pbr005179.1	GCAGTGATGCGGTGATCTAC	CCCAAACCAAAACTGGCCTT
PbACO3	Pbr031954.1	CAAGGATGGTGAATGGGTGGA	TCATCGCCTGGGTTGTAGAAC
PbACS1	Pbr015575.1	CCTGGGGTTCAAAGGGATCA	CCGCCGTTAAGACTACCCTA
PbACS2	Pbr019796.1	GTTGTGTCCGCAGCTACAAA	TGAGCCCACAAACAAGCATC
PbACS3	Pbr029891.1	GAAGTTTGGCAGCGAGTTCA	CAGATAGCATGGCGGAGAGA

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1.3 数据处理与分析

应用Excel和SPSS 13.0进行作图和方差分析。

2 结果

2.1 不同O₂浓度处理对生理病害发生的影响

2.1.1 虎皮指数 气调处理可显著降低贮藏和货架期间鸭梨虎皮病的发生,但不同O₂浓度处理对虎皮病的防控效果差异显著。具体来看,贮藏150 d,对照果实即发生虎皮病,气调果实均未发病;货架7 d,10% O₂处理果实的虎皮症状快速发展,虎皮指数达30.56%,与空气对照水平接近;贮藏210 d,5.0%及以下O₂处理平均虎皮指数为3.26%,10% O₂和空气对照虎皮指数分别为12.5%和38.56%;货架7 d,1.0%— 3.0% O₂处理平均虎皮指数为5.99%,5.0% O₂处理虎皮指数快速升高,达27.78%;贮藏270 d及货架7 d,1.0%—3.0% O₂平均虎皮指数18.86%,5.0% O₂平均虎皮指数35.0%,10.0% O₂平均虎皮指数54.95%,空气对照平均虎皮指数64.29%（图1）。另外,通过3年的中试库跟踪调查,采用3.0%—5.0% O₂+0.5%— 0.8% CO₂参数,鸭梨贮藏期可延长至翌年6月中下旬,虎皮病平均发生率<5.0%,且货架期≥7 d。

图1

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图1不同O₂浓度处理对鸭梨果实贮藏及货架期间黑心指数和虎皮指数的影响

不同小写字母表示0.05水平差异显著。下同
Fig. 1Effects of different oxygen concentrations on browning heart incidence and superficial scald incidence during storage and shelf-life period of Yali pear

Different lowercase letters indicate significant difference at 5% level. The same as below


2.1.2 黑心指数发生情况 气调处理可显著降低鸭梨贮藏150 d和210 d后果实黑心指数（P<0.05）;贮藏270 d及货架7 d,各处理果实黑心指数快速上升,从高到低依次为：CK（40%）>10.0% O₂（30.63%）>5.0% O₂（30.51%）>1.0% O₂（26.87%）>3.0% O₂（20.17%）>2.0% O₂（19.34%）,其中,1.0% O₂处理果实黑心指数显著高于2.0% O₂和3.0% O₂。3年的中试库黑心病跟踪调查表明,缓慢降温结合延迟气调（降温后30—35 d）,采用3.0%—5.0% O₂+0.5%— 0.8% CO₂处理,贮藏至翌年6月中下旬,黑心病平均发生率<3.0%,且货架期≥7 d。

2.2 不同O₂浓度处理对内在品质的影响

与采收时相比,各处理贮藏期间可滴定酸（TA）和抗坏血酸（AA）含量均显著下降。贮藏150 d,1.0%—3.0% O₂处理果实TA和AA含量均显著高于空气对照,5.0% O₂和10% O₂处理TA和AA含量与对照基本持平或略低,差异不显著;贮藏210 d,AA含量进一步降低,但货架7 d后,10.0% O₂和空气对照AA含量均显著高于低氧处理;贮藏270 d,各处理AA含量差异不显著,货架7 d后AA显著升高;贮藏270 d,2.0%、3.0%、5.0%及10.0% O₂处理TA含量均显著高于空气对照和1.0% O₂。同时,5.0%及以下O₂处理更好地保持了果实亮度及白度,贮藏270 d及货架7 d,L*值和b*值均显著高于10.0% O₂及空气对照（表2）。

Table 2
表2
表2不同O₂浓度处理贮藏货架期间鸭梨主要生理品质指标变化情况
Table 2Changes in the main quality attributes in Yali pear during storage and shelf-life periods in different oxygen concentrations

贮藏环境 Storage scenario	贮藏与 货架时间 Time (d)	品质指标 Quality parameters
		硬度 Firmness (kg?cm-2)	可溶性固形物 Soluble solids contents (%)	可滴定酸 Titratable acidity (%)	抗坏血酸 Ascorbic acid (mg/100 g)	L*	b*
基础值 At harvest		6.02±0.536	10.32±0.02	0.16±0.001	6.56±0.152	88.91±1.58	30.78±2.35
1.0% O2+0.5% CO2	150	5.48±0.335c	10.61±0.68cd	0.086±0.003a	4.62±0.178a	85.93±1.01a	23.86±1.15c
	150+10	5.10±0.424ab	11.00±0.483ab	0.042±0.001d	5.98±0.082b	86.93±0.72ab	32.59±2.05ab
	210	5.68±0.783a	10.54±0.505bc	0.081±0.001d	1.87±0.065a	88.15±1.24a	34.70±1.53bc
	210+7	5.65±0.752a	10.91±0.604a	0.13±0.001c	3.11±0.056c	87.30±1.0a	37.50±2.89a
	270	5.66±0.345a	11.07±0.892ab	0.085±0.002e	2.85±0.052a	86.32±1.55a	36.17±1.8ab
	270+7	5.62±0.404ab	10.39±0.713b	0.11±0.006c	3.78±0.209e	85.77±1.36a	37.82±2.37a
2.0% O2+0.5% CO2	150	5.59±0.355bc	10.87±0. 525bc	0.082±0.001b	3.51±0.137b	85.27±1.0abc	24.27±1.15bc
	150+10	5.24±0. 340ab	11.11±0.648a	0.043±0.001cd	5.04±0.004c	86.23±0.76bc	34.31±1.86a
	210	5.49±0.397a	10.96±0.463a	0.096±0.005b	1.33±0.057e	87.77±1.09a	35.96±2.53a
	210+7	5.26±0.295a	10.81±0.407a	0.15±0.001a	2.85±0.037e	87.11±0.70a	36.69±1.74a
	270	5.36±0.395b	11.19±0.543ab	0.088±0.003de	2.41±0.049d	86.41±1.48a	35.97±1.8b
	270+7	5.54±0.335c	10.86±0.661a	0.12±0.001a	2.90±0.053d	86.34±1.25a	37.26±2.33a
3.0% O2+0.5% CO2	150	5.70±0.529ab	11.38±0.466a	0.083±0.001b	2.74±0.911c	85.42±0.99c	25.32±1.18a
	150+10	5.38±0.489a	10.74±0.64b	0.045±0.003bc	5.00±0.043c	85.88±1.03c	34.32±1.81a
	210	5.48±0.482a	10.74±0.581ab	0.099±0.001b	1.49±0.033c	87.68±0.95a	35.76±1.23ab
	210+7	5.46±0.496a	10.87±0.701a	0.13±0.002b	3.02±0.034a	87.03±0.90a	36.11±1.43a
	270	5.82±0.565a	11.34±0.698a	0.10±0.001b	2.55±0.129bc	86.43±1.27a	37.21±1.71b
	270+7	5.50±0.486bc	10.38±0.929b	0.098±0.002d	3.55±0.014c	85.83±1.16a	37.45±2.4a
5.0%O2+0.5%CO2	150	5.84±0.468a	11.04±0. 542b	0.073±0.001d	2.50±0.438d	85.02±1.08bc	24.92±1.59ab
	150+10	5.32±0.64ab	10.88±0.527ab	0.047±0.001b	5.03±0.055c	87.14±1.16a	31.37±2.27b
	210	5.55±0.410a	10.62±0.58bc	0.097±0.002b	1.65±0.039b	88.08±1.11a	34.92±1.52abc
	210+7	5.68±0.725a	10.57±0.514ab	0.12±0.002d	2.87±0.044e	86.60±1.02b	37.79±2.31a
	270	5.32±0.538b	10.72±0.931cd	0.12±0.002a	2.47±0.018cd	87.02±1.56a	35.50±1.89b
	270+7	5.82±0.624a	10.48±0.939ab	0.11±0.002b	3.87±0.087bc	85.29±1.06a	37.82±2.59a
10.0% O2+0.5% CO2	150	5.46±0.343c	10.49±0.595d	0.077±0.003c	2.06±0.49e	85.60±1.36ab	24.03±1.19bc
	150+10	5.04±0.343bc	10.93±0.481ab	0.054±0.001a	4.67±0.049d	85.94±0.946c	33.33±0.83a
	210	5.49±0.403a	10.93±0.44a	0.11±0.001a	1.37±0.046d	87.79±1.22a	34.54±1.25c
	210+7	5.22±0.482a	10.87±0.337a	0.13±0.001b	3.53±0.043b	85.79±1.91c	36.65±2.31a
	270	5.26±0.422b	10.94±0.62bc	0.095±0.001c	1.64±0.025b	84.03±4.51b	35.82±1.55b
	270+7	5.23±0.387d	10.35±0.685b	0.12±0.001a	4.07±0.161b	84.04±1.63ab	36.97±2.68a
空气 Air control	150	5.51±0.280bc	10.48±0.625d	0.069±0.001e	2.58±0.263cd	84.49±1.8c	24.22±1.03bc
	150+10	4.81±0.263c	10.84±0.475ab	0.045±0.001b	6.14±0.115a	87.16±0.95a	31.38±1.77b
	210	5.14±0.293b	10.49±0.451c	0.077±0.001c	1.43±0.031cd	87.28±1.97a	35.07±1.32abc
	210+7	5.32±0.258b	10.43±0.611b	0.11±0.002e	3.85±0.005a	85.25±4.35d	36.65±2.47a
	270	5.28±0.263b	10.38±0.692d	0.090±0.002d	1.88±0.032a	83.59±2.32b	35.26±1.34b
	270+7	5.38±0.577cd	10.10±0.702b	0.10±0.002d	4.67±0.117a	81.83±1.77b	27.42±2.13a

Different small letters in same column indicated significant differences at 0.05 level among different oxygen treatments at the same period
同列数据后不同小写字母表示各处理同一时期在0.05水平差异显著

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另外,贮藏150 d时,各处理及对照果实硬度均快速下降,可溶性固形物含量上升;贮藏210 d和270 d,所有处理及对照果实硬度和可溶性固形物含量相对稳定,且不同处理及对照间无显著差异。

2.3 不同O₂浓度处理对乙醇含量的影响

贮藏150 d,不同处理及对照间果肉和果心组织中乙醇含量差异显著,其中5.0%及以下O₂处理果实乙醇含量均显著高于10.0% O₂和空气对照,其中1.0% O₂处理果实果肉和果心组织中乙醇含量最高,分别为806.12和750.20 mg?L^-1;其次为2.0% O₂处理;10.0% O₂和空气对照乙醇含量均<200 mg?L^-1;贮藏150 d后货架10 d,5.0%及以下O₂处理果实乙醇含量呈下降趋势,10.0%和空气对照处理则呈上升趋势。贮藏210 d及货架7 d、贮藏270 d及货架7 d,1.0% O₂处理果实乙醇含量保持相对稳定,乙醇平均含量约为700 mg?L^-1;2.0%、3.0%、5.0%及10.0% O₂处理乙醇略有上升,但基本稳定在500 mg?L^-1左右;贮藏270 d及货架7 d,空气处理果实果肉和果心组织褐变加重,组织塌陷,平均乙醇含量超过1 500 mg?L^-1（图2）。

图2

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图2不同O₂浓度贮藏及货架期间鸭梨乙醇变化情况

Fig. 2Effects of different oxygen concentrations on ethanol content during storage and shelf-life period of Yali pear

2.4 不同O₂浓度处理对呼吸速率和乙烯的影响

5.0%及以下O₂处理果实贮藏150、210及270 d后,其乙烯产量均显著低于10.0% O₂和空气对照,其中1.0% O₂乙烯释放量最低,贮藏150、210及270 d,温度平衡后（回升到20℃）,其乙烯释放速率分别为46.83、88.04和76.65 μL?kg^-1?h ^-1;2.0%—3.0% O₂释放量次之;货架10 d或7 d后,低氧处理乙烯释放量快速上升。贮藏150和210 d,低氧气调贮藏果实呼吸速率均显著低于空气对照,但不同O₂浓度处理间差异不显著;贮藏270 d及货架7 d,低氧气调处理与对照果实呼吸速率差异不显著（图3）。

图3

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图3不同O₂浓度贮藏及货架期间鸭梨呼吸和乙烯变化情况

Fig. 3Effects of different oxygen concentrations on respiration rate and ethylene production during storage and shelf-life period of Yali pear

2.5 不同O₂浓度处理对乙烯生物合成关键基因相对表达量的影响

整体来看,与对照相比,采用低氧气调处理可显著抑制鸭梨货架初期果皮组织中PbACS1、PbACO1及PbACO3表达,推迟货架期间果皮组织中乙烯合成相关基因表达高峰,但不同O₂处理下PbACS2、PbACS3及PbACO2表达无明显规律（数据未列出）。具体来看,贮藏150 d,1.0%—3.0% O₂处理PbACS1相对表达量极低,但5.0%和10.0% O₂处理及空气对照PbACS1相对表达量较高;气调贮藏果实PbACO1和PbACO3相对表达量均显著低于空气对照;贮藏150 d后货架10 d,1.0%— 3.0% O₂处理PbACS1相对表达量较出库时增长近45倍,各处理PbACO1和PbACO3相对表达量快速上升,且5.0%及以下O₂处理基因表达量均显著高于10.0%及空气对照;随着贮藏期的延长,乙烯合成相关基因表达水平上升,贮藏210 d及货架7 d,空气处理PbACS1相对表达量达到峰值,10% O₂处理PbACO1和PbACO3达到峰值;贮藏270 d后货架7 d,1.0—3.0% O₂处理PbACS1和PbACO1仍保持相对较高水平（图4）。

图4

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图4不同O₂浓度贮藏及货架期间PbACO1、PbACO3及PbACS1表达情况

Fig. 4The relative expression of PbACO1, PbACO3 and PbACS1 under different oxygen concentrations during storage and shelf-life period of Yali pear

3 讨论

3.1 环境O₂浓度与虎皮病和黑心病发生的关系

虎皮病是梨采后贮藏过程中一种主要的生理病害^[26]。低氧处理可有效降低果实贮藏期间活性氧（ROS）的积累,降低乙烯释放量,有效降低α-法尼烯及其氧化产物共轭三烯醇的积累,进而抑制虎皮病的发生^[27,28]。近年来,超低氧气调贮藏技术（O₂<1.0%）和动态气调贮藏技术（O₂<0.6%）快速发展,与传统气调贮藏相比,更低的贮藏环境O₂浓度能更好地控制苹果和梨采后虎皮病的发生^[29,30]。本研究中,5.0%及以下O₂处理显著降低了鸭梨长期贮藏过程中虎皮病的发生,货架期显著延长,其中1.0%—3.0% O₂处理防控虎皮病效果最佳。可见,进一步降低贮藏环境氧气浓度可更好地维持鸭梨果实外观品质,延长货架期,这与前人研究结论一致。

黑心病发生的直接原因是细胞膜发生过氧化反应,细胞膜完整性被打破,多酚氧化酶（PPO）催化酚类底物形成醌,进而诱发褐变^[31,32]。低氧胁迫处理可通过调控氧化代谢平衡进而降低衰老相关生理病害的发生^[33,34]。本研究中,采用阶段降温结合延迟气调贮藏均显著降低了贮藏和货架期间果实黑心病的发生,相对更低的O₂浓度更好地控制了贮藏后期（270 d）果心褐变指数,但过低的氧气浓度处理（1.0% O₂）一定程度上增加了鸭梨果实贮藏末期黑心病风险。

3.2 环境O₂浓度与内在品质变化的关系

超低氧气调贮藏（O₂<1.5%）是苹果商业生产中常用的一项技术^[35],但在梨商业生产中应用很少,主要原因是多数梨品种对过低O₂敏感,过低的O₂会造成果实发生无氧呼吸进而造成乙醇大量积累,诱发果心组织褐变,果实风味品质下降,例如‘Williams Bon Chretien’在1.0% O₂处理下仅能贮藏4个月^[36]。但同时也有研究表明,适量乙醇作为一种低抗氧化物可明显降低苹果和梨等采后贮藏过程中虎皮病的发生^{[37,38,39,40]}。本研究中,5.0%及以下O₂处理果实乙醇含量贮藏前期显著高于10.0%和空气对照,适量乙醇的积累可能一定程度上增强了果实抗性,进而抑制了鸭梨后期虎皮病的发生,但乙醇抗氧化阈值及伤害极值仍需进一步研究确定。

CHENG等^[3]研究发现,1-MCP处理可以显著降低乙烯产量,较好地维持鸭梨果实冷藏期间TA含量水平,较好地维持果实品质降低黑心指数。杜艳民等^[23]研究发现鸭梨贮藏过程中TA含量与黑心指数显著相关,可作为预测鸭梨黑心病的指标。本研究中,果实可滴定酸（TA）含量随着贮藏时间的延长不断下降,与空气对照相比,2.0%、3.0%、5.0%及10.0% O₂处理较好地维持了贮藏后期（270 d）TA含量,并显著高于空气对照和1.0% O₂,且TA含量越低,黑心指数越高,该结论与前人研究结果一致。

抗坏血酸（AA）作为一种抗氧化物质,可与谷胱甘肽等其他抗氧化物质协同清除活性氧分子。前人研究发现,低氧气调处理果实AA含量显著低于普通冷藏;同时,梨的研究发现,不同黑心病诱导处理下,AA含量与果实黑心病敏感性显著相关,当AA含量低于特定阈值时,果实黑心病敏感性增强^[41]。本研究中,与空气对照相比,低氧处理更好地维持了贮藏前期果实AA含量,但随着贮藏期的推迟,低氧处理和对照AA含量均进一步降低,且处理与对照间差异变小且不显著;但货架7 d或10 d后,低氧处理和空气对照AA含量均显著升高,初步推测与货架期间果实进一步衰老后,活性氧等衰老相关组分含量增加有关,但其生物学功能和作用机制仍需进一步研究。

3.3 环境O₂浓度与乙烯生物合成的关系

鸭梨是一种典型的采后呼吸跃变型果实,贮藏过程及货架期间释放大量的乙烯;ACS和ACO是乙烯生物合成途径中的关键限速酶,且在番茄和梨中均由多家族基因控制^[42,43]。本研究结合前人研究基础及检索梨基因组,初步获得PbACO1、PbACO2、PbACO3、PbACS1、 PbACS2及PbACS3等6个乙烯合成关键基因;其中PbACO1、PbACO3及PbACS1在低氧处理下相对表达量显著降低,基因表达高峰与10.0% O₂及对照相比明显推迟。但随着货架期的延长,乙烯合成相关基因表达量快速升高,而且贮藏后期及货架后,低氧气调贮藏乙烯释放速率显著高于空气对照处理,因此,低氧气调处理对乙烯的抑制是可逆的,乙烯合成代谢会随着环境温度和氧气浓度回升而恢复,该发现与前人研究结果一致^[18],但更低的O₂浓度会进一步推迟货架期间乙烯的合成,延缓衰老。

4 结论

1.0%—3.0% O₂处理能更好地抑制鸭梨采后虎皮病的发生,推迟乙烯释放高峰,延缓果实可滴定酸和抗坏血酸含量下降;显著抑制了果皮组织中PbACO1、PbACO3及PbACS1表达,能更好地维持果皮亮度及白度,鸭梨贮藏期明显延长。但1.0% O₂处理在一定程度上增加了鸭梨贮藏末期黑心病风险。因此,建议生产中鸭梨储藏最佳O₂浓度参数为3.0%—5.0%。

（责任编辑 赵伶俐）

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[1] 王文辉, 贾晓辉, 杜艳民, 王志华 . 我国梨果生产与贮藏现状存在的问题与发展趋势
保鲜与加工, 2013,13(5):1-8.
[本文引用: 1]

WANG W H, JIA X H, DU Y M, WANG Z H . Current situation, problems and development trend of production and storage of pear in China
Storage and Process, 2013,13(5):1-8. (in Chinese)
[本文引用: 1]

[2] CAO J K, JIANG W B . Induction of resistance in Yali pear (Pyrus bretschneideri Rehd.) fruit against postharvest diseases by acibenzolar-S-methyl sprays on trees during fruit growth
Scientia Horticulturae, 2006,110:181-186.
DOI:10.1016/j.scienta.2006.07.002URL [本文引用: 1]

[3] CHENG Y D, LIU L Q, FENG Y X, DONG Y, GUAN J F . Effects of 1-MCP on fruit quality and core browning in ‘Yali’ pear during cold storage
Scientia Horticulturae, 2019,243:350-356.
DOI:10.1016/j.scienta.2018.08.041URL [本文引用: 2]

[4] YAN S J, LI L, HE L H, LIANG L Y, LI X D . Maturity and cooling rate affects browning, polyphenol oxidase activity and gene expression of ‘Yali’ pears during storage
Postharvest Biology and Technology, 2013,85:39-44.
DOI:10.1016/j.postharvbio.2013.04.016URL [本文引用: 1]
Browning is the main physiological disorder of 'Yali' pear (Pyrus bretschneideri Rehd) during storage. In this study, the relationships between browning development in fruit from different harvest dates, and cooled either rapidly or slowly, with polyphenol oxidase (PPO) activity and isozymes, and PPO gene expression has been investigated. Development of browning was highest in late-harvest fruit in both core and flesh tissues and was higher in rapidly cooled than slowly cooled fruit. Mid-harvest fruit had the lowest browning incidence and PPO activity of core tissue was higher than in flesh and seeds, while the peak of PPO activity in mid-harvest fruit was the lowest. Six PPO isoenzymes were detected in fruit, three bands A, B and E in flesh and core tissues, three bands C, D and F in the seeds. The intensity of PPO isoenzyme staining of bands A and B in pulp and core was similar to that of PPO activity and browning incidence. PPO gene expression increased and then decreased in core tissues. Trends of expression were similar to those of PPO activity. Rapid cooling promoted the expression PPO. The results suggest PPO plays an important role in 'Yali' pear browning during storage. (c) 2013 Elsevier B.V.

[5] 杜艳民, 王文辉, 贾晓辉, 乐文全, 魏建梅, 关军锋 . 河北省梨果贮藏产业发展现状及建议
保鲜与加工, 2017,17(2):1-6.
[本文引用: 1]

DU Y M, WANG W H, JIA X H, LE W Q, WEI J M, GUAN J F . Development status and proposal of pear storage industry of Hebei province
Storage and Process, 2017,17(2):1-6. (in Chinese)
[本文引用: 1]

[6] DRAKE S R, MIELKE E A, ELFVING D C . Maturity and storage quality of ‘Concorde’ pears
Hort Technology, 2004,14(2):250-256.
[本文引用: 1]

[7] THOMPSON K . Controlled Atmosphere Storage of Fruits and Vegetables. 2nd ed
UK: Oxford shire, 2010: 272.
[本文引用: 1]

[8] ALMEIDA D P F, CARVALHO R, DUPILLE E . Efficacy of 1-methylcyclopropene on the mitigation of storage disorders of ‘Rocha’ pear under normal refrigerated and controlled atmospheres
Food Science and Technology Interview, 2016,22:399-409.
[本文引用: 1]

[9] SAQUET A A . Storage of pears
Scientia Horticulturae, 2019,246:1009-1016.
DOI:10.1016/j.scienta.2018.11.091URL [本文引用: 1]

[10] CALVO G, SALVADOR M E, SANCHEZ E . Control of superficial scald in Beurré d’Anjou pears with low oxygen levels
Acta Horticulture, 2002,596:879-882.
[本文引用: 1]

[11] RIZZOLO A, GRASSI M, VANOLI M . 1-Methylcyclopropene application, storage temperature and atmosphere modulate sensory quality changes in shelf-life of ‘AbbéFétel’ pears
Postharvest Biology and Technology, 2014,92:87-97.
DOI:10.1016/j.postharvbio.2014.01.010URL [本文引用: 1]
'Abbe Fetel' is the most important pear cultivar in Italy but is susceptible to superficial scald and soft scald during storage, the former is effectively prevented by 1- methylcyclopropene (1-MCP) treatment at harvest and by dynamic controlled atmosphere (DCA). However, 1-MCP at -0.5. C prevents pear ripening, and DCA can favor the appearance of soft scald, specially after long storage. The aim of this research was to study the sensory profiles of 1-MCP treated (SmartFreshTM, 300 nL L-1) and untreated 'Abbe Fetel' pears after 20 and 28 weeks of storage at -0.5 degrees C and 1 degrees C in normal air (NA), controlled atmosphere (CA) and DCA and up to 7 days of post-storage shelf-life at 20 degrees C, and their relationships with mechanical characteristics of the pulp (firmness, stiffness and energy-to- rupture) and sugar (SSC) and acids (TA) content. During storage and shelf-life, untreated fruit softened, more at 1 degrees C than at -0.5. C, and to a greater extent after 28 weeks of storage, while 1-MCP treated pears on average showed higher values of firmness, stiffness and energy-to- rupture than untreated fruit, independently of storage time and days of shelf-life. Mechanical properties of the pulp were positively correlated with sensory firmness and negatively with juiciness, sweetness and aroma, the three descriptors positively correlated with overall acceptability. Cluster analysis carried out on sensory scores separately for 20 and 28 weeks samples underlined that, within either untreated or 1-MCP treated samples, similar sensory profiles could be obtained in response to the diverse combinations of storage atmosphere, storage temperature and day of shelf-life. The most preferred sensory profile (juicy, not grainy, sweet, aromatic, quite sour and less astringent) was obtained for untreated pears after 20 weeks storage at -0.5. C in CA, independently of time of shelf-life and in NA and DCA after 4 and 7 days of shelf-life, as well as in DCA pears stored at 1 degrees C after 4 and 7 days of shelf-life. In contrast, the worst sensory characteristics (grainy, not firm, not juicy, not sweet, not sour, very astringent and not aromatic) distinguished untreated pears after 28 weeks storage at 1 degrees C in NA. After 20 weeks storage, the two sensory profiles of 1- MCP treated fruit were both characterized by firm texture associated with graininess but differing for the flavor description, and were less preferred by the assessors. After 28 weeks storage it was possible to distinguish the sensory profile of 1- MCP treated pears stored at -0.5 degrees C after 4 and 7 days of shelf-life, from that of 1- MCP treated pears stored at 1 degrees C after 3 days of shelf-life. Both profiles were characterized by a firm/quite grainy texture but differed for flavor, the former being less sweet, less sour, less astringent and less aromatic than the latter. (C) 2014 Elsevier B.V.

[12] RIZZOLO A, GRASSI M, VANOLI M . Influence of storage (time, temperature, atmosphere) on ripening, ethylene production and texture of 1-MCP treated ‘AbbéFétel’ pears
Postharvest Biology and Technology, 2015,109:20-29.
DOI:10.1016/j.postharvbio.2015.06.003URL [本文引用: 1]

[13] VANOLI M, GRASSI M, RIZZOLO A . Ripening behavior and physiological disorders of ‘Abate Fetel’ pears treated at harvest with 1-MCP and stored at different temperatures and atmospheres
Postharvest Biology and Technology, 2016,111:274-285.
DOI:10.1016/j.postharvbio.2015.09.017URL [本文引用: 1]

[14] SAQUET A A, STREIF J, ALMEIDA D P F . Responses of ‘Rocha’ pear to delayed controlled atmosphere storage depend on oxygen partial pressure
Scientia Horticulturae, 2017,222:17-21.
DOI:10.1016/j.scienta.2017.05.006URL [本文引用: 1]

[15] NGUYEN T A, VERBOVEN P, SCHENK A, NICOLAI B M . Prediction of water loss from pears (Pyrus communis cv. Conference) during controlled atmosphere storage as affected by relative humidity
Journal of Food Engineering, 2007,83:149-155.
DOI:10.1016/j.jfoodeng.2007.02.015URL [本文引用: 1]

[16] PEDRESCHI R, HERTOG M, ROBBEN J, NOBEN J P, NICOLAI B M . Physiological implications of controlled atmosphere storage of ‘Conference’ pears (Pyrus communis L.): A proteomic approach
Postharvest Biology and Technology, 2008,50:110-116.
DOI:10.1016/j.postharvbio.2008.04.004URL [本文引用: 1]

[17] SAQUET A A . Storability of Conference pear under various controlled atmospheres
Erwerbs-Obstbau , 2018,60:1-6.
[本文引用: 1]

[18] 陈昆松, 于梁, 周山涛 . 鸭梨果实气调贮藏研究
园艺学报, 1991,18(2):131-137.
[本文引用: 2]

CHEN K S, YU L, ZHOU S T . A study on controlled atmosphere storage of ‘YA-LI’ pears
Acta Horticulture Sinica, 1991,18(2):131-137. (in Chinese)
[本文引用: 2]

[19] 陈昆松, 于梁, 周山涛 . 鸭梨果实气调贮藏过程CO₂伤害机理初探
中国农业科学, 1991,24(5):83-88.
URL [本文引用: 1]
鸭梨果实采后对CO#-2极为敏感，尤其是果心组织。于5%-7% O#-2+0.6%或3.0%CO#-2环境中贮藏50天后，果心组织便出现不同程度的伤害而发生褐变；当O#-2浓度一定，CO#-2浓度越高，伤害褐变越严重，但果肉和果皮组织无褐变出现：果心褐变指数与果心组织的酚类物质含量呈显著负相关（r=-0.8868**），与多酚氧化酶活性呈显著正相关（r=0.8890**）；CO#-2伤害引起的组织褐变，首先是细胞内膜系统被破坏。
CHEN K S, YU L, ZHOU S T . A preliminary study on possible mechanism of CO₂ injury of ‘YA-LI’ pear (Pyrus bretschneideri Rehd.) during CA storage
Scientia Agicultura Sinica, 1991,24(5):83-88. (in Chinese)
URL [本文引用: 1]
鸭梨果实采后对CO#-2极为敏感，尤其是果心组织。于5%-7% O#-2+0.6%或3.0%CO#-2环境中贮藏50天后，果心组织便出现不同程度的伤害而发生褐变；当O#-2浓度一定，CO#-2浓度越高，伤害褐变越严重，但果肉和果皮组织无褐变出现：果心褐变指数与果心组织的酚类物质含量呈显著负相关（r=-0.8868**），与多酚氧化酶活性呈显著正相关（r=0.8890**）；CO#-2伤害引起的组织褐变，首先是细胞内膜系统被破坏。

[20] 陈昆松, 于梁, 周山涛 . 雪花梨和鸭梨贮藏特性比较
植物生理学通讯, 1992,28(6):428-430.
[本文引用: 1]

CHEN K S, YU L, ZHOU S T . Comparison of storage character of Xuehua pear and Ya pear
Plant Physiology Communication, 1992,28(6):428-430. (in Chinese)
[本文引用: 1]

[21] HOHN E, DATWYLER D, GASSER F, DE JAGER A, JOHNSON D, HOHN E . Maturity indices to predict optimum harvest date for the storage of ‘Conference’ pears in Switzerland//Determination and Prediction of Optimum Harvest Date of Apples and Pears
Brussels, 1996: 148-156. ECSC-EC-EAEC.
[本文引用: 1]

[22] VERLINDENBE, DE JAGER A, LAMMERTYN J, SHOTSMANS W, NICOLAI B . Effect of harvest and delaying controlled atmosphere storage conditions on core breakdown incidence in ‘Conference’ pears
Biosystems Engineering, 2002,83:339-347.
DOI:10.1006/bioe.2002.0127URL [本文引用: 1]

Abstract

A logistic regression model was built to describe the effect of picking time and the most relevant commercially applied storage factors on the incidence of core breakdown in pears (Pyrus communis L. cv. Conference). The statistical analysis showed that the probability of core breakdown depended on several variables in a more complicated way than assumed before. In general, more mature fruit, stored at lower O₂ and higher CO₂ concentrations, at a higher temperature and for longer times are more susceptible to core breakdown. However, delaying the controlled atmosphere (CA) conditions for 21 days decreased the core breakdown incidence efficiently even for late-picked fruit. Together with a proper delay of CA, a sufficiently high O₂ concentration during CA was most important. The model was validated with data of 16 orchards gathered over five harvest seasons in two countries which gives it a wide validity range and a high practical relevance.

[23] 杜艳民, 王文辉, 贾晓辉, 佟伟, 王志华 . 不同可溶性固形物含量鸭梨耐贮性差异比较
果树学报, 2018,35(10):1262-1270.
[本文引用: 2]

DU Y M, WANG W H, JIA X H, TONG W, WANG Z H . The comparison of storage ability of‘Yali’pear in different soluble solids contents grades
Journal of Fruit Science, 2018,35(10):1262-1270. (in Chinese)
[本文引用: 2]

[24] 纪淑娟, 尹竞男, 李家政, 黄艳凤 . 静态顶空气相色谱法测定蜜柚中乙醇和乙醛含量
保鲜与加工, 2010,10(4):17-20.
[本文引用: 1]

JI S J, YIN J N, LI J Z, HUANG Y F . Determination of alcohol and acetaldehyde in pomelo by static head space gas chromatography
Storage and Process, 2010,10(4):17-20. (in Chinese)
[本文引用: 1]

[25] 慕茜 . 五种水果作物果实成熟过程中乙烯合成及应答途径相关基因的功能分析
[D]. 南京: 南京农业大学, 2015.
[本文引用: 1]

MU Q . Functional analysis of the ethylene biosynthesis and signaling pathway related genes during the ripening of five species of fruit crops
[D]. Nanjing: Nanjing Agricultural University, 2015. (in Chinese)
[本文引用: 1]

[26] LURIE S, WATKINS C B . Superficial scald, its etiology and control
Postharvest Biology and Technology, 2012,65:44-60.
DOI:10.1016/j.postharvbio.2011.11.001URL [本文引用: 1]
Superficial scald is a physiological disorder causing brown or black patches on fruit skin that appears during or after storage on apples and pears. At least partial control of the disorder can be obtained from application of antioxidants, especially the commonly used diphenylamine (DPA), as well as low oxygen storage; scald development is assumed to be an oxidative process. However, the etiology and biochemistry that leads to its development are not completely understood. This is an overview of the evidence for and against the hypothesis that a-farnesene oxidation products cause the damage resulting in skin browning. It discusses the recent findings on the genes involved in alpha-farnesene synthesis and oxidation, and their induction or repression by abiotic stresses and ethylene. Methods of control of scald development other than antioxidants are reviewed, including recent developments in controlled atmospheres, ethylene inhibitors and stress treatments. In addition, recent research on the use of metabolic approaches to understand the changes occurring during the induction period for scald in the fruit is discussed. (C) 2011 Published by Elsevier B.V.

[27] SABBAN-AMIN R, FEYGENBERG O, BELAUSOV E, PESIS E . Low oxygen and 1-MCP pretreatments delay superficial scald development by reducing reactive oxygen species (ROS) accumulation in stored ‘Granny Smith’ apples
Postharvest Biology and Technology, 2011,62:295-304.
DOI:10.1016/j.postharvbio.2011.06.016URL [本文引用: 1]
'Granny Smith' apples are highly susceptible to superficial scald, a symptom of chilling injury. For many crops, low temperature storage results in oxidative stress and chilling injury, caused by increased production of superoxide anions which in turn leads to the generation of other dangerous reactive oxygen species (ROS). Application, prior to cold storage, of low oxygen (LO2, <0.5%) atmospheres, ethanol (<2% vapour) or 1-methylcyclopropene (1-MCP, 0.5 mu L L-1) at 20 degrees C, was effective in reducing superficial scald in fruit following 24 weeks of cold storage. ROS levels were measured by confocal laser-scanning microscopy of apple peel treated with the fluorescent probe 2',7'-dichlorodihydrofluorescein diacetate. In control fruit. ROS levels increased during cold storage and shelf-life and were very high after only 8 weeks, whereas in 1-MCP-, ethanol- and LO2-treated fruit, ROS levels remained low throughout storage. Gene-expression levels of ROS-scavenging enzymes were induced by the various pretreatments: catalase (MdCAT) was induced by LO2 treatment, whereas Mn superoxide dismutase (MdMnSOD) was induced by 1-MCP treatment. Polyphenol oxidase (MdPPO) gene expression levels were associated with scald symptom development and were highest in control fruit. Ethylene levels and expression of ethylene biosynthesis genes were correlated with a-farnesene levels and alpha-farnesene synthase (MdAFS) gene expression in the variously treated fruit. Accumulation of the a-farnesene oxidation product, 6-methyl-5-hepten-2-one (MHO), was highest in control fruit after 8 weeks, in accordance with ROS accumulation. The LO2 pretreatment mechanism might involve production of anaerobic metabolites, causing a delay in ethylene and alpha-farnesene biosynthesis and oxidation; this is different from the mechansism of action of 1-MCP, even though both consequently reduce ROS accumulation and scald symptoms. (C) 2011 Elsevier BM.

[28] BORDONABA J G, MATTHIEU-HURTIGER V, WESTERCAMP P, COUREAU C, DUPILLE E, LARRIGAUDIERE C . Dynamic changes in conjugated trienols during storage may be employed to predict superficial scald in ‘Granny Smith’ apples
LWT-Food Science and Technology, 2013,54:535-541.
DOI:10.1016/j.lwt.2013.06.025URL [本文引用: 1]
In order to predict scald disorders in 'Granny Smith' apples, fruit were harvested from three different orchards and stored in controlled storage regimes of 2.5 kPa 02/2.5 kPa CO2 (CA) and 0.7 kPa 02/0.5 kPa CO2 (Ultra low oxygen; ULO) or in air after treatment with 1-MCP. Relationships between different oxidative markers (hydrogen peroxide, antioxidant potential, malondialdehyde), compounds related to alpha-farnesene metabolism (alpha-farnesene, conjugated trienols (CTols) including CTol(258) and CTol(281)) and scald incidence were established. Our results showed that neither changes in fruit antioxidant potential, malondialdehyde nor the generation of hydrogen peroxide during storage were associated to scald and hence were not able to predict scald incidence. The ratio between conjugated trienols (CTol(258)/CTol(281)) failed to predict scald susceptibility on a short- or mid-term basis. In contrast, a novel and accurate model based on CTols accumulation dynamics (dCTols/dt) during early stages of storage (<50 days) is proposed. After validation of the model, a threshold value of delta CTols/delta t >= 5.5 is defined to predict scald occurrence in 'Granny Smith' apples. (C) 2013 Elsevier Ltd.

[29] DELELEL M A, BESSEMANS N, GRUYTERS W, ROGGE S, JANSSEN S, VERLINDEN B E, SMEETS B . Spatial distribution of gas concentrations and RQ in a controlled atmosphere storage container with pear fruit in very low oxygen conditions
Postharvest Biology and Technology, 2019,156:110903.
DOI:10.1016/j.postharvbio.2019.05.004URL [本文引用: 1]

[30] BRENTON C P, JAMES P M, DAVID R R . Extending ‘Granny Smith’ apple superficial scald control following long term ultra-low oxygen controlled atmosphere storage
Postharvest Biology and Technology, 2020,161:111062.
DOI:10.1016/j.postharvbio.2019.111062URL [本文引用: 1]

[31] 鞠志国, 朱广廉, 曹宗巽 . 莱阳茌梨果实褐变与多酚氧化酶及酚类物质区域化分布的关系
植物生理学报, 1988,14(4):356-361.
[本文引用: 1]

JU Z G, ZHU G L, CAO Z X . The compartmentation of polyphenol oxidase and its substrates in relation with fruit browning of Laiyang Chi Li (Pyrus bretschneideri Rehd)
Acta Phytophysiologica Sicica, 1988,14(4):356-361. (in Chinese)
[本文引用: 1]

[32] CHENG Y D, LIU L Q, ZHAO G Q, SHENG G G, YAN H B, GUAN J F, YANG K . The effects of modified atmosphere packaging on core browning and the expression patterns of PPO and PAL genes in ‘Yali’ pears during cold storage
LWT-Food Science and Technology, 2015,60:1243-1248.
DOI:10.1016/j.lwt.2014.09.005URL [本文引用: 1]

[33] LUM G B, DEELL J R, BOZZO G G . Oxidative metabolism is associated with physiological disorders in fruits stored under multiple environmental stresses
Plant Science, 2016,245:143-152.
DOI:10.1016/j.plantsci.2016.02.005URLPMID:26940499 [本文引用: 1]
In combination with low temperature, controlled atmosphere storage and 1-methylcyclopropene (ethylene antagonist) application are used to delay senescence of many fruits and vegetables. Controlled atmosphere consists of low O2 and elevated CO2. When sub-optimal partial pressures are used, these practices represent multiple abiotic stresses that can promote the development of physiological disorders in pome fruit, including flesh browning and cavities, although there is some evidence for genetic differences in susceptibility. In the absence of surface disorders, fruit with flesh injuries are not easily distinguished from asymptomatic fruit until these are consumed. Oxidative stress metabolites tend to accumulate (e.g., gamma-aminobutyrate) or rapidly decline (e.g., ascorbate and glutathione) in vegetative tissues exposed to hypoxic and/or elevated CO2 environments. Moreover, these phenomena can be associated with altered energy and redox status. Biochemical investigations of Arabidopsis and tomato plants with genetically-altered levels of enzymes associated with the gamma-aminobutyrate shunt and the ascorbate-glutathione pathway indicate that these metabolic processes are functionally related and critical for dampening the oxidative burst in vegetative and fruit tissues, respectively. Here, we hypothesize that gamma-aminobutyrate accumulation, as well energy and antioxidant depletion are associated with the development of physiological injury in pome fruit under multiple environmental stresses. An improved understanding of this relationship could assist in maintaining the quality of stored fruit.

[34] LUM G B, DEELL J R, HOOVER G J, SUBEDI S, DEELL J R, BOZZO G G . 1-Methylcylopropene and controlled atmosphere modulate oxidative stress metabolism and reduce senescence-related disorders in stored pear fruit
Postharvest Biology and Technology, 2017,129:52-63.
DOI:10.1016/j.postharvbio.2017.03.008URL [本文引用: 1]

[35] WRIGHT A H, DELONG J M, ARUL J, PRANGE R K . The trend toward lower oxygen levels during apple (Malus domestica Borkh) storage
Journal of Horticulture Science and Biotechnology, 2015,90(1):1-13.
[本文引用: 1]

[36] KUPFERMAN E . Controlled Atmosphere Storage of Apples and Pears
Postharvest Information Network, Washington State University, 2001: 1-8.
[本文引用: 1]

[37] WANG Z Y, DILLEY D R . Initial low oxygen stress controls superficial scald of apples
Postharvest Biology and Technology, 2000,18:201-213.
DOI:10.1016/S0925-5214(00)00067-3URL [本文引用: 1]

[38] PESIS E, BEN-ARIE R, FEYGENBERG O, LICHTER A, GADIYEVA O, ANTILOFYEV I, URYUPINA T . A simple pretreatment with low O₂ to alleviate superficial scald in Granny Smith apples
Journal of the Science of Food and Agriculture, 2007,87:1836-1844.
DOI:10.1002/(ISSN)1097-0010URL [本文引用: 1]

[39] LARRIGAUDIERE C, CANDAN A P, GINE-BORDONABA J, CIVELLO M, CALVO G . Unravelling the physiological basis of superficial scald in pears based on cultivar differences
Scientia Horticulturae, 2016,213:340-345.
DOI:10.1016/j.scienta.2016.10.043URL [本文引用: 1]

[40] LARRIGAUDIERE C, LINDO-GARCIA V, UBACH D, GINE- BORDONABA J . 1-Methylcyclopropene and extreme ULO inhibit superficial scald in a different way highlighting the physiological basis of this disorder in pear
Scientia Horticulturae, 2019,250:148-153.
DOI:10.1016/j.scienta.2019.02.049URL [本文引用: 1]

[41] VELTMAN R H, KHO R M, VAN SCHAIK A C R, SANDERS M G, OOSTERHAVEN J . Ascorbic acid and tissue browning in pears (Pyrus communis L. cvs Rocha and Conference) under controlled atmosphere conditions
Postharvest Biology and Technology, 2000,19:129-137.
DOI:10.1016/S0925-5214(00)00095-8URL [本文引用: 1]

[42] BARRY C S, GIOVANNONI J J . Ethylene and fruit ripening
Journal of Plant Growth Regulation, 2007,26:143-159.
DOI:10.1007/s00344-007-9002-yURL [本文引用: 1]
The ripening of fleshy fruits represents the unique coordination of developmental and biochemical pathways leading to changes in color, texture, aroma, and nutritional quality of mature seed-bearing plant organs. The gaseous plant hormone ethylene plays a key regulatory role in ripening of many fruits, including some representing important contributors of nutrition and fiber to the diets of humans. Examples include banana, apple, pear, most stone fruits, melons, squash, and tomato. Molecular exploration of the role of ethylene in fruit ripening has led to the affirmation that mechanisms of ethylene perception and response defined in the model system Arabidopsis thaliana are largely conserved in fruit crop species, although sometimes with modifications in gene family size and regulation. Positional cloning of genes defined by ripening defect mutations in the model fruit system tomato have recently led to the identification of both novel components of ethylene signal transduction and unique transcription factor functions influencing ripening-related ethylene production. Here we summarize recent developments in the regulation of fruit ripening with an emphasis on the regulation of ethylene synthesis, perception, and response.

[43] CHIRIBOGA M, SALADIE M, BORDONABA J, RECASENS I, GARCIA-MAS J, LARRIGAUDIERE C . Effect of cold storage and 1-MCP treatment on ethylene perception, signaling and synthesis: Influence on the development of the evergreen behavior in ‘Conference’ pears
Postharvest Biology and Technology, 2013,86:212-220.
DOI:10.1016/j.postharvbio.2013.07.003URL [本文引用: 1]
To further understand the response of 'Conference' pears to 1-methylcyclopropene (1-MCP) treatment and their ability to restore ripening after prolonged periods of cold storage, fruit were treated with 0, 300 nL L-1 1-MCP or 300 nL L-1 exogenous ethylene plus 600 nL L-1 1-MCP prior to storage. Changes in ethylene, ethylene precursors (ACC, MACC), ethylene-related enzyme activities (ACS, ACO) together with their transcript levels, and the expressioii of four ethylene receptors and one Raf kinase protein from the ethylene signalling pathway, were monitored before and after cold storage and during subsequent ripening at 20 degrees C.
1-MCP treatment acted on the ethylene pathway in two differentiated phases. In a first initiation occurring during cold storage, the 1-MCP treatment limited the up-regulation of both PcACS1 and PcACO1 observed in control fruit and promoted an up-regulation of PcETR1 leading to a complete inhibition of ACO activity during cold storage. These regulations resulted in fruit unable to produce ethylene upon removal and promoted the second phase (maintenance phase). This second phase was characterized by a dawn-regulation of PcACS1 and PcACS4 as well as PcACO1 together with a clear up-regulation of PcETR5 and better maintenance of PcCTR1 transcript levels, which were partially reversed with exogenous ethylene treatment. All these different regulations led in turn to a complete inhibition of the ripening processes, which may partially explain the occurrence of the evergreen behaviour in 'Conference' pear during shelf-life. (C) 2013 Elsevier B.V.