冷激处理对芒果贮藏冷害及相关酶的影响

为探讨减轻芒果冷害的新途径,研究了0℃冷激处理3、45、h对芒果2℃贮藏12 d的冷害症状、贮藏品质及3种同工酶的影响。结果表明:0℃冷激处理3、45、h均显著降低了果实在2℃下贮藏期间的冷害指数和冷害率,0℃处理4 h的冷害指数最低,比对照果低60%,冷害率比对照果低32%,0℃冷激处理4 h促进了芒果贮藏期间可溶性固形物含量的上升,降低了可滴定酸的含量,延缓了抗坏血酸的含量的下降,对硬度的影响不大;同工酶电泳显示:0℃冷激处理4 h提高了芒果贮藏中后期ATP酶、细胞色素氧化酶、过氧化物酶的活性。     

冷害对采后“大五星”枇杷果实贮藏品质及木质化败坏的影响

研究冷害对采后"大五星"枇杷果实贮藏品质及木质化的影响,旨在阐明冷害温度下枇杷果实品质劣变,特别是木质化败坏的规律,为枇杷贮藏保鲜提供理论依据。"大五星"枇杷采后分别于冷害温度[(3±1)℃,简称3℃]和非冷害温度[(8±1)℃,简称8℃]贮藏30d,定期测定贮藏期间两组的品质及相关指标变化。结果表明,3℃条件下枇杷果实在第10天开始出现冷害症状,随后日趋严重,而在8℃条件下的果实30d内发生冷害程度很轻。冷害会加速枇杷采后失重率、膜透性、木质素、PAL、POD活性的上升,促进TSS、TA和VC含量下降。     

H_2O_2处理对采后黄瓜抗冷性的影响

为了减轻冷敏型果实黄瓜(Cucumis sativus L.)冷藏中的冷害问题,用0.001,0.010,0.100mmol·L-1过氧化氢(H2O2)溶液和冷激、热激对黄瓜果实处理后,在2℃冷藏中观测了果实的冷害发生情况、色度变化、H2O2和丙二醛(MDA)含量。0.010mmol·L-1H2O2处理与对照蒸馏水处理比较,冷害发生率和冷害指数低,色度值变化小,H2O2和MDA含量低;0.010mmol·L-1H2O2处理后减轻冷害效果好于冷激处理,与热激处理接近。表明冷藏前用外源H2O2处理可以提高黄瓜果实冷藏中的抗冷性,减轻冷害。     

Reduction of Chilling Injury and Ultrastructural Damage in Cherry Tomato Fruits After Hot Water Treatment

The effects of hot water treatment in alleviating chilling injury and reducing ultrastructural damage of mature-green cherry tomatoes （Lycopersicun esculentum cv. cerasiform Alef） were investigated. Mature-green cherry tomato fruits were treated in water at 40℃ or 45℃ for 5 min or 15 min, and then stored at 5℃ for 19 days followed by ripening at 20℃. Water treatment at 40℃ for 15 min increased tolerance of cherry tomato fruits to chilling stress, indicating as low outbreak of skin lesion, high color a＊ value, and low electrolyte leakage. Treated fruits showed typical climacteric respiration and developed normal red color with chlorophyll degradation and lycopene accumulation during ripening, while fruits without treatment failed to develop red color and suffered skin lesion. After 19 days of chilling, heated fruits showed the conversion of chloroplast to chromoplast with the disappearance of thylakoids. Mitochondria and other cell organelles were not adversely affected in treated fruits. However, ultrastructures in pericarp cells in control fruits severely damaged with extensive disorganization of cytoplasm, swelled chloroplasts, distorted and unstacked thylakoids. Chloroplast was the first and most severely impacted organelle by chilling stress. Hot water treatment （40℃ for 15 min） before storage alleviated chilling injury in cherry tomato fruits. The results suggest that chilling injury is related with the damage of cell structure under chilling stress.     

青椒果实低温贮藏及冷害生理的研究

本试验研究了辣椒果实采后在10℃、7℃、4℃、1℃四个不同温度下的生理生化变化、贮藏效果、以及低温下冷害发生的规律。结果表明:10℃是辣椒果实冷藏的安全温度,采后初期的低温虽明显地抑制了辣椒果实的后熟,但随贮期的延长,7℃及以下的低温均对果实产生了不同程度的冷害,表现为果实的呼吸强度、MDA含量、相对电导率异常开高;冷害指数的变化与腐烂指数的变化是显著的正相关关系;且4℃处理的辣椒果实冷害发生更早,程度更严重。     

橄榄果实的冷藏适温与冷害初报

檀香橄榄果实在２、６、１０℃下进行贮藏试验．结果表明，低温可以抑制橄榄果实的呼吸作用，延缓呼吸高峰的出现，抑制过氧化物酶（ＰＯＤ）和过氧化氢酶（ＣＡＴ）活性，延缓果实的成熟衰老，抑制病原菌的生长．２、６℃低温下橄榄果实细胞电解质渗漏升高，当渗漏率达到５．００ｍｍｓ－１时（贮藏６０ｄ）果实遭受不可逆的冷害．１０℃贮温下的橄榄果实贮藏效果最好，贮藏６０ｄ，好果率仍保持１００％，失重率为１．９９％，肉质脆嫩，果皮、果肉、果核均未发生褐变，具有新鲜果实的原有风味、颜色和品质．建议在６－１０℃下进一步探讨橄榄果实的冷藏适温     

外源腐胺处理对黄皮甜瓜采后冷害及品质的影响

[目的]研究外源腐胺(Putrescine,Put)处理对黄皮甜瓜冷害的控制效果,筛选适宜的外源腐胺处理浓度,为生产中甜瓜果实采后冷害调控提供理论依据.[方法]以黄皮甜瓜新密3号为试材,分别用0、1.0、1.5和2.0 mmol/L 4个不同浓度外源Put处理后,置于5℃、相对湿度75％ ～80％条件下贮藏,定期统计黄...     

李子冷藏中间歇加温处理对果实低温伤害、呼吸及乙烯的影响

本试验研究了不同的间歇加温温度和加温时间对低温下贮藏的李子呼吸强度、乙烯释放量的影响，通过这些生理生化变化规律，结合货架期果肉褐变及腐烂的观察，对李子的冷害发生规律进行了探讨。结果表明：间歇加温可有效地降低呼吸、乙烯的产生，减轻或延缓了果实的低温冷害。但加温的温度不同对李子的腐烂影响不一致．３０℃加温虽可减轻冷害，但由于温度过高，软化、腐烂严重；而２０℃加温处理不但可减轻冷害，有利于品质保持，而且腐烂轻。因此，李子在低温下贮藏的最佳间歇加温处理为：每隔１５天，在２０℃中加温１～２天。     

热空气处理诱导冷藏橄榄果实抗冷性及其与膜脂代谢的关系

【目的】研究热空气处理对冷藏橄榄果实抗冷性的影响及其与脂氧合酶（LOX）活性和膜脂脂肪酸组分变化的关系。【方法】采后‘檀香’橄榄[Canarium album (Lour.) Raeusch cv. Tanxiang]果实38℃热空气处理30 min,采用0.015 mm厚的聚乙烯薄膜袋密封包装,在（2?1）℃下贮藏。贮藏期间定期测定橄榄果实冷害指数和细胞膜透性,果皮LOX活性和膜脂脂肪酸组分。【结果】与对照果实比,38℃热空气处理30 min降低冷藏橄榄果实冷害指数、细胞膜透性和果皮LOX活性,提高果皮棕榈油酸（C16:1）、亚油酸（C18:2）和亚麻酸（C18:3）等不饱和脂肪酸相对含量,降低肉豆蔻酸（C14:0）、棕榈酸（C16:0）和硬脂酸（C18:0）等饱和脂肪酸相对含量,抑制果皮脂肪酸不饱和指数和脂肪酸不饱和度下降。【结论】热空气处理通过降低冷藏橄榄果实果皮LOX活性而减少膜脂不饱和脂肪酸的降解,维持较高的膜脂脂肪酸不饱和程度,从而增强橄榄果实抗冷性、减轻冷藏橄榄果实冷害的发生。     

MaHSFA1和MaHSP70在热处理诱导香蕉抗冷性中的作用

【目的】探讨MaHSFA1和MaHSP70基因在热处理诱导香蕉抗冷性中的作用,为有效延长香蕉贮运期提供参考依据。【方法】从香蕉基因组数据库(http://banana-genome.cirad.fr/)中搜索到MaHSFA1和MaHSP70基因序列,分别设计特异引物,利用实时荧光定量PCR(qRT-PCR)检测这2个基因在香蕉热处理和低温贮藏中的表达情况。【结果】MaHSFA1基因与其他物种的HSFA1基因同源性较低,仅在HSF DNA-bind区域的保守性很高;MaHSP70基因含有一个HSPA1-2,6-8-like NBD区域,且与其他物种的HSP70基因同源性很高。7℃冷藏诱导香蕉果实的MaHSFA1和MaHSP70基因表达量整体上呈下降趋势。经52℃热水处理诱导的MaHSFA1基因表达增强,且在热激处理后0.5 h有一个小高峰;在7℃低温贮藏过程中,经热处理后的MaHSFA1基因表达量在贮藏4.0 h时迅速升高至最大值,之后又迅速下降;MaHSP70基因表达量在热激处理后0.5 h迅速升高至最大值,约是对照处理(未经热激处理)的4倍,之后逐渐下降。在整个试验过程中除7℃贮藏120.0 h外,其他时段热激处理的MaHSFA1和MaHSP70基因表达量均高于对照处理。【结论】采后香蕉果实的抗冷性与MaHSFA1和MaHSP70基因表达增强密切相关,生产上可通过热处理提高香蕉果实的抗冷性,进而延长贮运期。     

脱落酸、水杨酸和钙对黄瓜幼苗抗冷性的诱导效应

为了探明脱落酸(ABA)、水杨酸(SA)和氯化钙(CaCl2)对黄瓜幼苗抗冷性的影响及其生理机制,以津优35号黄瓜幼苗为试材,叶面喷施0.1 mmol.L-1 ABA、1 mmol·L-1 SA和10 mmol·L-1 CaCl2,以喷洒去离子水为对照(CK),在光照培养箱中进行低温(昼/夜温度8℃/5℃,光量子通量密度为100μmol.m-2·s-1)处理.结果表明,低温胁迫可使黄瓜幼苗的冷害指数、电解质渗漏率(EL)、丙二醛(MDA)和过氧化氢(H2O2)含量显著升高.随着胁迫时间的延长,过氧化物酶(POD)活性逐渐升高,而超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、谷胱甘肽还原酶(GR)活性先升高,后降低;脯氨酸与可溶性糖含量明显增加.胁迫前经ABA、SA和CaCl2预处理,黄瓜幼苗的冷害指数分别比CK降低50.0％、40.0％和47.1％,EL和MDA含量的增加幅度明显减小,胁迫初期H2O2含量增加幅度大于CK,但24 h后呈下降趋势,72 h时分别比CK降低27.9％、27.5％和34.4％;抗氧化酶活性及脯氨酸、可溶性糖含量显著高于CK.说明ABA、SA和CaCl2对黄瓜幼苗抗冷性有明显的诱导效应,这种效应与抗氧化酶活性提高和渗透调节能力增强有关.     

外源ABA对棉花幼苗抗寒性的影响初探

[目的]研究脱落酸(ABA)在低温(5℃)条件下对棉花幼苗电导百分率、MDA含量、SOD活性的影响.[方法]以中棉所15号为材料,分别进行5℃低温处理0、2、4、6、12、24、48和72 h和ABA浓度0、10-8、10-7、10-6和10-5mol/L交叉处理,并做二因素方差分析和Duncan多重比较.[结论]低温时间和ABA浓度均极显著影响电导率、MDA含量、SOD活性,且低温时间和ABA浓度之间无相互作用; 5℃低温及ABA 10-7 mol/L条件下处理4 h,能极显著降低棉花幼苗电导百分率和MDA含量,提高SOD活性.在低温5℃、4 h、ABA 10-7 mol/L处理下比较中棉所15号、中棉所35号、新陆早8号三种棉花品种的抗寒性.[结论]抗寒能力大小为:中棉所15号>中棉所35号>新陆早8号.     

Exogenous Application of Abscisic Acid (ABA) Enhances Chilling Tolerance in Seedlings of Napier Grass (Pennisetum purpureum Schum.)

Napier grass, an important forage crop with potentials in multi-purpose applications, is widely grown throughout the tropics and subtropics. Low temperature severely limits its productivity and geographical distribution in temperate regions of the world. In this study, we investigated the effect of exogenous abscisic Acid(ABA) on chilling tolerance of napier grass(Pennisetum purpureum Schum.) seedlings. Seven-day-old napier grass seedlings were cultured in dd H_2O or ABA solution at different concentrations and exposed to 1 ℃ for different time durations. The chilling injury, membrane stability index(MSI) and proline content were estimated from leaf samples. The results showed that there was obvious morphological injury of leaf blighting and restrained growth for the seedlings under chilling stress, but this damage can be largely reduced(by 2/3) when the seedlings were treated by 100 μmol/L ABA in the culture solution, and that the application of exogenous ABA can help to maintain a good stability of leaf cell membrane as expressed by a high MSI value and a low level of proline in leaf cells. These results suggested that exogenous ABA can significantly alleviate chilling injury in napier grass seedlings by maintaining the stability of leaf cell membrane during chilling stress, and that the chilling tolerance was not ensured by a proline accumulation although a passive accumulation of proline was observed in the seedlings under chilling stress. Our results lay a preliminary foundation for future investigations on the molecular mechanisms of ABA induced chilling or freezing tolerance in napier grass.     

NO处理延缓采后枇杷果实木质化劣变及其与能量代谢的关系

【目的】枇杷果实采后生命活动旺盛,衰老速度快,常温下极易变质腐烂。低温贮藏虽然可以有效延长贮藏期,减少腐烂,但会出现果皮难以剥离、果肉木质化并褐变、质地糙硬少汁等品质劣变现象,这是造成冷藏枇杷商品性丧失和损失的主要原因,已成为其市场拓展的限制因素,是当前枇杷果实在冷链集散和流通中急需解决的关键问题。探讨外源NO处理对冷藏枇杷果肉木质化劣变进程的作用机制,并分析木质化劣变与能量代谢的关系,以期为进一步研究采后枇杷果实低温品质劣变进程调控的分子生物学机理和贮运保鲜技术奠定基础。【方法】将‘解放钟’枇杷（Eriobotrya japonica Lindl.）果实在密闭容器中用0（对照组）、15和25 μL•L-1 NO熏蒸2 h后,取出通风20 min,然后将各处理果实置于5℃、相对湿度85%条件下贮藏,测定冷藏期间各处理组果实细胞膜透性、硬度、出汁率、木质素含量、ATP含量、ADP含量、AMP含量、能荷值及琥珀酸脱氢酶（SDH）、细胞色素氧化酶（CCO）、H+-ATPase和Ca2+-ATPase活性的变化,并分析NO处理后木质素含量与能荷值间的相关性。【结果】随着贮藏时间的延长,枇杷果实细胞膜透性和硬度逐渐上升,出汁率逐渐下降,贮藏10 d后木质素含量迅速上升,果实冷害症状明显。与对照组相比, NO处理能延缓细胞膜透性和硬度的上升及出汁率的降低,显著抑制木质素的合成,较好地保持细胞膜的完整性,从而减轻果实冷害的发生。冷藏期间,枇杷果实ATP含量逐渐下降,贮藏前10 d ADP含量迅速下降并最终维持在较低水平,贮藏中后期（15-30 d）SDH、CCO、H+-ATPase和Ca2+-ATPase活性急剧下降,表明线粒体功能受损导致枇杷果实能荷水平迅速下降。与对照组相比,NO处理可以延缓ATP、ADP含量的下降,且显著抑制贮藏中后期SDH、CCO、H+-ATPase和Ca2+-ATPase活性的降低,保持枇杷果实较好的线粒体功能;贮藏30 d后,15 和25 μL•L-1 NO处理的枇杷果实能荷值分别比对照组高11.8%和12.9%。相关性分析表明,15和25 μL•L-1 NO处理的枇杷果实能荷值和木质素含量呈极显著负相关,相关系数（r）分别为 -0.715**、-0.598**。【结论】低温条件下,能量代谢失调与枇杷果实木质化劣变密切相关,NO处理可以通过调节SDH、CCO、H+-ATPase、Ca2+-ATPase线粒体代谢相关酶活性,维持较高的能量水平,从而有效地提高冷藏枇杷果实抗低温的能力,进而延缓果实木质化进程,其中以25 μL•L-1 NO处理效果较好。     

Exogenous Application of Abscisic Acid(ABA) Enhances Chilling Tolerance in Seedlings of Napier Grass(Pennisetum purpureum Schum.)

Napier grass, an important forage crop with potentials in multi-purpose applications, is widely grown throughout the tropics and subtropics. Low temperature severely limits its productivity and geographical distribution in temperate regions of the world. In this study, we investigated the effect of exogenous abscisic Acid(ABA) on chilling tolerance of napier grass(Pennisetum purpureum Schum.) seedlings. Seven-day-old napier grass seedlings were cultured in dd H_2O or ABA solution at different concentrations and exposed to 1 ℃ for different time durations. The chilling injury, membrane stability index(MSI) and proline content were estimated from leaf samples. The results showed that there was obvious morphological injury of leaf blighting and restrained growth for the seedlings under chilling stress, but this damage can be largely reduced(by 2/3) when the seedlings were treated by 100 μmol/L ABA in the culture solution, and that the application of exogenous ABA can help to maintain a good stability of leaf cell membrane as expressed by a high MSI value and a low level of proline in leaf cells. These results suggested that exogenous ABA can significantly alleviate chilling injury in napier grass seedlings by maintaining the stability of leaf cell membrane during chilling stress, and that the chilling tolerance was not ensured by a proline accumulation although a passive accumulation of proline was observed in the seedlings under chilling stress. Our results lay a preliminary foundation for future investigations on the molecular mechanisms of ABA induced chilling or freezing tolerance in napier grass.     

不同贮藏温度对青椒生理性状的影响

青椒属冷敏性果实,贮运中不适宜的低温易引起果实冷害发生。以克新6号青椒为试材,测定了1、5、10℃贮藏温度下青椒果实品质及几种生理指标的变化。结果表明:在1、5℃下贮藏果实,20d后果面开始出现冷害症状,冷害果细胞膜透性增大,丙二醛积累峰提早出现,果实维生素C和叶绿素损失加快,但低温明显抑制果实的呼吸强度。与1℃处理相比,5℃处理下青椒果实冷害发生更早,程度更严重。10℃下贮藏果实未出现冷害,是克新6号青椒冷藏的适宜温度。     

“绿化9号”桃果实软化及果胶代谢中乙醛作用的影响

以晚熟品种“绿化9号”桃为试材,用0,0．5,1．0和2．0mL／kg乙醛处理果实12h后,分别贮藏于室温（20±1）℃和（0±1）℃下,研究桃果实软化及果胶物质代谢中乙醛的作用。结果表明：2个温度下,乙醛处理有抑制桃果实呼吸强度的作用。0℃下,2．0mL／kg和1．0mL／kg乙醛处理可抑制果实果胶甲酯酶（PE）和β-半乳糖苷酶（β-Gal）活性的增加,减轻果实软化,但对原果胶含量和可溶性果胶含量的影响不显著;室温下,乙醛处理促进PE,β-Gal活性的增加和可溶性果胶含量的上升,以及果实软化。PG活性受乙醛处理的影响,与果实硬度、原果胶和可溶性果胶含量等关联性不明显。     

活性氧在热处理诱导香蕉耐冷性中的作用

【目的】探讨活性氧在热处理诱导果实耐冷性中的作用。【方法】采用10 μmol•L-1的活性氧合成酶NADPH氧化酶的专一性抑制剂二苯基碘（diphenylene iodonium, DPI）预处理香蕉果实,然后于52℃热水处理3 min,之后置于7℃低温贮藏,测定冷害指数、叶绿素光化学效率Fv/Fm、过氧化氢（H2O2）和超氧阴离子（ ）含量、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性及其基因表达。【结果】与单独热水处理香蕉果实相比,热处理前预先用DPI处理的香蕉果实具有较高的冷害指数和较低的Fv/Fm值;在冷藏前3 d减少了由热处理导致的H2O2含量和 产生速率的快速积累;降低了CAT和APX的活性;抑制了MaCAT和MaAPX基因的表达。【结论】DPI预处理减少了香蕉果实由于热处理而导致的活性氧的迅速积累,相应地也减弱了热处理诱导的耐冷效果,表现为冷害症状加剧。推测热水处理诱导的早期活性氧爆发为香蕉果实的耐冷诱导所必需,其可能作为信号分子参与了此过程。     

Melatonin treatment alleviates chilling injury in mango fruit 'Keitt' by modulating proline metabolism under chilling stress

Mangoes often suffer from low temperature-induced chilling injury (CI) during postharvest cold storage.  Therefore, advanced techniques are crucial and in high demand to solve the chilling stress of mango fruit for a higher value.  This study addresses chilling stress modulation by investigating the effects of melatonin treatment on CI, proline metabolism, and related gene expressions of ‘Keitt’ mango during cold storage after dipped in 0 (control), 0.1 (MT1), and 0.2 mmol L^–1 (MT2) melatonin solution for 30 min.  The results revealed that melatonin treatment in MT1 significantly reduced CI development and increased proline content in mango fruit during cold storage compared to the control.  These changes were along with increases in the activity of critical enzymes as well as the expression of encoding genes involved in proline biosynthesis, such as pyrroline-5-carboxylate synthetase (P5CS), pyrroline-5-carboxylate reductase (P5CR), ornithine D-aminotransferase (OAT), P5CS2, P5CR2, and OAT3.  Additionally, proline dehydrogenase (PDH) activity and the expression of the PDH3 gene associated with proline dehydrogenation were lower in MT1-treated mangoes than the controlled group.  Thus, melatonin treatment has regulated proline metabolism resulting in the accumulation of proline, subsequently contributing to enhancing the chilling tolerance of ‘Keitt’ mango fruit.