不同成熟方式对红玉杏果实品质的影响

为比较树上成熟和自然放熟两种红玉杏果实的品质差异,对果实的基本理化指标、可溶性糖含量、有机酸含量、矿物质微量元素含量进行了测定,并采用SPME-GC/MS技术检测了其中的挥发性香气成分。结果表明:自然放熟红玉杏果实除可食率、pH、出汁率、果胶总量比树上成熟略低,其余基本理化指标及营养成分均高于树上成熟红玉杏;自然放熟红玉杏果实中大部分香气物质种类及总含量均高于树上熟杏,色泽口感芳香气味等品质均高于树上成熟红玉杏果实。     

茶多酚处理对杏果实贮藏期主要抗氧化酶活性的影响

采用不同浓度的茶多酚处理金太阳杏果实,分析茶多酚处理对金太阳杏贮藏过程中几个主要抗氧化酶活性的影响以及不同浓度处理间的差异.结果表明:与对照果实相比,0.1%和0.2%茶多酚处理能明显减缓杏果实贮藏期POD、CAT活性的降低,0.4%茶多酚处理对抗氧化酶活性下降的减缓作用不太明显,而0.6%茶多酚处理反而在一定程度上加快了POD、CAT活性的降低;茶多酚处理对杏果实贮藏期SOD活性的影响不明显.由此认为,较低浓度的茶多酚处理对杏果实在贮藏期抗氧化酶系统有一定的激活作用,有利于杏果实的贮藏;而较高浓度的茶多酚处理对抗氧化酶活性降低的减缓作用不明显,反而加速了部分抗氧化酶活性的降低,从而加速果实的衰老.     

不同成熟期杏品种光合特性差异分析

[目的]了解所选9个不同成熟期杏品种的光合特性,为进一步研究不同成熟期杏品种光合特性差异,及与其果实发育的相关性奠定基础.[方法]在果实第二次缓慢生长期(即6月上旬～7月上旬),测定各品种光响应和CO2响应曲线.[结果]9个不同成熟期杏品种光及CO2响应曲线的变化趋势基本相同,但不同熟期类型光合特征模拟参数值间存在极显著差异.光合能力以早熟品种巴都玉吕克、库买提最强,而晚熟品种中的大果胡安娜和亚布拉克佳娜丽相对较弱,极晚熟品种冬杏居中.影响不同成熟期杏品种果实发育期的主要因素为AQY、LCP、LSP、CE、CCP、CSP.极晚熟品种冬杏除了受AQY、LCP、LSP、CE、CCP、CSP的影响外,较高的Rd是其发育期延长的关键因素之一.[结论]9个不同成熟期杏品种的光合特性模拟参数值在相同熟类型品种之间差异显著,不同熟期类型品种之间存在极显著差异.光合特性模拟参数中,AQY、LSP、CE、CCP、CSP与果实发育期的长短密切相关,较高Rd值是造成极晚熟品种冬杏果实发育期较长的关键因素之一.     

不同气体组合对杏果实贮藏品质的影响

以银白和苹果白杏果实为试材,探讨了不同气调处理,即气体O2与CO2 6种比例组合:3% O2(CA1)、3% O2+2%CO2(CA2)、3%O2+4%CO2(CA3)、8%O2 (CA4)、8%O2+2%CO2(CA5)、8%O2+4%CO2(CA6)及对照(21% O2)对杏果实贮藏品质的影响.结果表明:在相同的贮藏时间内,气调贮藏可缓解银白杏果实硬度的下降,CA6处理的作用最明显,其次为CA3和CA4处理;冷藏苹果白杏果实的硬度在贮藏后期增加,气调贮藏果实的硬度降低,但处理间的差异不显著.在贮藏30 d内,冷藏银白杏果实的可溶性固形物和VC含量仍较高,贮藏30～45 d两者明显下降,气调贮藏可缓解其下降,CA3处理的效果最明显;气调贮藏对苹果白杏果实可溶性固形物和VC含量的影响不大.气调贮藏可缓解银白和苹果白杏果实可滴定酸含量的下降.可见,CA3处理对维持银白杏果实贮藏品质有较好的作用;气调贮藏对苹果白杏果实品质的影响表现在可滴定酸方面,CA1和CA2的效果较好.     

亚精胺处理对小白杏货架期品质的影响

以绿熟期小白杏为试验材料,研究亚精胺处理小白杏后对其货架期品质的影响。用1×10-4,1×10-5,1×10-6 mol/L亚精胺溶液处理绿熟期小白杏,以喷蒸馏水为对照(CK),放在室温(25±2)℃条件下,模拟货架期,连续7d测定果实硬度、可溶性固形物、可滴定酸、维生素C、腐烂率。以1×10-4 mol/L亚精胺处理的效果最好,能有效抑制杏果硬度下降,减少可溶性固形物和可滴定酸的消耗,延缓维生素C的下降,降低腐烂率。不同浓度亚精胺溶液处理小白杏,对其货架期品质有一定的影响,而适宜浓度的亚精胺溶液则能保持小白杏货架期的品质。     

金太阳杏果实生长发育及各生长指标的相关性分析

在果实生长发育期,通过测定果实纵径、横径、侧径、体积、鲜重及干重,研究了金太阳杏果实发育规律。结果表明:金太阳杏果实的生长发育动态呈“慢—快—慢—快—慢”的“双S”形曲线,整个发育过程可分为5个时期:幼果缓慢生长期、果实第1次迅速生长期、果实第2次缓慢生长期、果实第2次迅速生长期和果实熟前缓慢生长期。果实纵、横、侧径与果实鲜重、体积变化曲线极为相似,并具有同步增长的趋势。同时建立起各生长指标的生长模型曲线。     

乙烯利和ABA处理对‘金魁’猕猴桃果实后熟软化的生理效应

研究了乙烯利和ABA处理对‘金魁’美味猕猴桃采后生理及内源激素的影响。结果表明：‘金魁’果实属典型的呼吸跃变型果实，具有明显的呼吸跃变和乙烯释放高峰。乙烯利和ABA处理显著地促进了果实的呼吸和乙烯释放，加速果实硬度的下降，从而加速果实的后熟衰老，相比之下，乙烯利较ABA更能促进果实的成熟和软化。同时乙烯利和ABA处理还促进了果实内源ABA的积累．加速IAA和GA3水平的下降。     

不同成熟度杏果实采后抗坏血酸和超氧自由基代谢的变化

本文以两种成熟度的杏果实为材料,研究了杏果实采后膜脂过氧化与果实成熟衰老的关系。结果表明:两种成熟度杏果的膜脂过氧化特征不同,且采后均具有叶绿素和抗坏血酸降解的特征,绿熟果实中叶绿素和抗坏血酸降解与(?)产生速率升高呈显著的正相关。绿熟杏果实采后(?)产生速率持续升高,SOD活性和丙二醛含量先是快速增加而后下降;黄熟杏果实采后(?)产生速率、SOD活性和丙二醛含量则呈下降趋势。说明超氧自由基代谢失衡,导致膜脂过氧化加剧是果实成熟哀老的原因之一。     

杏果实采后细胞壁组份及水解酶活性变化研究

以6个早、中、中晚熟新疆杏品种为材料,采后贮藏于(3.0±0.5)℃,定期测定果实贮期细胞壁含量、细胞壁组成物质含量、果胶酶、纤维素酶和β-葡萄糖苷酶活性的变化,研究果实采后贮藏过程细胞壁及相关水解酶变化特性.结果表明,贮藏期间,6个品种杏果实硬度、细胞壁含量下降,果胶酶和纤维素酶活性升高,促进了原果胶和纤维素的降解,纤维素、半纤维素和共价结合型果胶含量下降,细胞壁水溶性果胶和离子型果胶含量明显上升,最终导致果实的软化.6个杏品种中,中熟品种轮台小白杏硬度和细胞壁含量高于其他品种,表现为较耐贮藏;早熟品种巴都玉吕克含量最低,差异显著(P＜0.05),表现为不耐贮藏,进一步解释了中熟及中晚熟杏耐贮原因.     

不同贮藏温度对杏果实品质的影响

以九成熟的"银白"、"苹果白"杏果实为试材,研究了不同温度(-0.5 ℃、0.5 ℃、1.5 ℃)贮藏处理对杏果实品质的影响.结果表明,这两个品种杏果实均在1.5 ℃贮藏条件下软化较快,而0.5 ℃贮藏条件对于维持果实硬度有较好的作用;经过45 d贮藏,与-0.5 ℃和0.5 ℃贮藏条件相比,1.5 ℃贮藏的银白、苹果白杏果实SSC和TA含量均最高;至贮藏结束时,3个温度贮藏银白、苹果白杏果实维生素C含量均出现下降,但处理间差异不显著.综上所述,0.5 ℃贮藏有利于保持银白、苹果白杏果实商品性状,1.5 ℃贮藏能有效地延缓银白、苹果白杏果实SSC、TA、维生素C降解.     

1-MCP对‘绿宝石’梨采后成熟衰老期间H2O2含量及其相关酶活性的影响

为探讨1-甲基环丙烯(1-MCP)对梨果实采后成熟衰老过程中过氧化氢(H2O2)代谢的作用,试验以‘绿宝石’梨为材料,用1.0 μL/L 1-MCP密封处理24 h,空气密封为对照,研究1-MCP对‘绿宝石’梨室温(25±2)℃贮藏过程中果实硬度、可溶性同形物含量(SSC)、呼吸速率、H2O2含量、抗氧化酶活性[超氧化...     

GA3延缓不同成熟度杏果实后熟的生理效应

仰韶黄杏采后用２００mg/kgＧＡ３处理,能有效地延缓杏果实的成熟衰老过程,其生理效 应与延缓叶绿素降解,促进ＰＯＤ和抑制ＰＰＯ活性,调节细胞膜脂过氧化代谢膜脂过氧化代谢活性有关。同时探讨了两种不同成熟度杏果实成熟衰老代谢和ＧＡ３调节效应的差异。     

草莓果实采后NAD激酶活性与NAD（H）、NADP（H）含量及活性氧代谢的关系

【目的】研究草莓采后成熟衰老过程中NADK活性与NAD（H）、NADP（H）及活性氧代谢和膜氧化产物变化的关系，以探讨NADK在非跃变型果实成熟衰老过程中的作用，为调控果实的成熟衰老提供理论依据。【方法】将从果园采回的草莓果实贮藏于不同的温度下并进行每天取样，研究草莓果实在低温（4℃）、常温（20℃）贮藏期间成熟衰老过程中NAD激酶（NADK）活性及其底物NAD（H）、产物NADP（H）以及超氧阴离子O2- •过氧化氢（H2O2）、膜氧化产物丙二醛（MDA）含量的变化并分析NADK 与上述指标的关系。【结果】草莓果实在低温（4℃）贮藏时，其NADK活性比常温（20℃）贮藏的高，NAD（H）含量则相应比常温贮藏的低，NADP（H）含量则高于常温下的；同时，在常温贮藏期间果实O2- •生成速率和H2O2含量、膜氧化产物MDA含量均比低温贮藏的高，暗示NADK可能通过影响NAD（H）、NADP（H）的含量及比例来调控O2- •生成速率和H2O2含量，从而调控果实的成熟衰老。【结论】非跃变型果实草莓采后成熟衰老过程中，保持较高的NADK活性有利于延缓果实的成熟衰老，降低NADK活性可导致NAD和NAD（H）含量的积累，进而加速电子传递，产生大量的活性氧O2- •和H2O2，从而促进膜过氧化作用和积累较多的MDA，最终导致果实衰老变质。     

Effects of 1-Methylcyclopropene on NO Content, NOS Activity, and H2O2 Content in Postharvest Suli Pears

Studies were conducted over the effects of 1-methylcycolpropene (1-MCP) treatment on postharvest life of Suli pears (Pyrus bretschneideri Rehd.) stored at room and cold temperatures on nitric oxide (NO), nitric oxide synthase (NOS)activity, and hydrogen dioxide (H2O2). Results showed that the 1-MCP treatment had little effect on total soluble solids (TSS) at both room and cold temperatures. 1-MCP delayed softening of Suli pear fruits, decreased respiratory rate and H2O2 accumulation, and increased NO and NOS activity at room temperature storage, while the effect of cold temperature storage was relatively inferior. There was a significant positive correlation between NOS activity and NO content. It is concluded that 1-MCP had effects on endogenous NO content and accumulation of H2O2. Similarly, H2O2 acting as a signaling molecule via regulating NO level affects the ripening and senescence of Suli pears.     

Effects of high CO_2 treatment on green-ripening and peel senescence in banana and plantain fruits

Banana fruit(Musa,AAA group,cv.Brazil) peel fails to fully degreen but the pulp ripens normally at temperatures above24°C.This abnormal ripening,known as green-ripening,does not occur in plantains(Musa,ABB group,cv.Dajiao).Based on the fact that un-completely yellowing was also observed for bananas in poorly ventilated atmospheres,in the present study,the effect of high CO_2 with regular O_2(21%) on banana ripening was investigated along with that on plantains at20℃.The results showed that high CO_2 conferred different effects on the color changing of bananas and plantains.After6 d ripening in 20%CO_2,plantains fully yellowed,while bananas retained high chlorophyll content and stayed green.In contrast to the differentiated color changing patterns,the patterns of the softening,starch degradation and soluble sugar accumulation in the pulp of 20%CO_2 treated bananas and plantains displayed similarly as the patterns in the fruits ripening in regular air,indicating that the pulp ripening was not inhibited by 20%CO_2,and the abnormal ripening of bananas in 20%CO_2 can be considered as green ripening.Similar expression levels of chlorophyll degradation related genes,SGR,NYC and PaO,were detected in the peel of the control and treated fruits,indicating that the repressed degreening in 20%CO_2treated bananas was not due to the down-regulation of the chlorophyll degradation related genes.Compared to the effect on plantains,20%CO_2 treatment delayed the decline in the chlorophyll florescence(F√F_m values and in the mRNA levels of a gene coding small subunit of Rubisco(SSU),and postponed the disruption of the ultrastructure of chloroplast in the peel tissue of bananas,indicating that the senescence of the green cells in the exocarp layer was delayed by 20%CO_2,to more extent in bananas than in plantains.High CO_2 reduced the ethylene production and the expression of the related biosynthesis gene,ACS,but elevated the respiration rates in both cultivars.The up-regulation of the expression of anaerobic respiration pathway genes,ADH and PDC,might be responsible for the subtle effect of high CO_2 on the pulp ripening.Taken together,the atmosphere of high CO_2 and regular O_2,delayed the senescence of the green cells in the exocarp layer of the banana peel,but conferred no obvious inhibition on the pulp ripening,leading to a distinct green-ripening that was different from the phenomenon induced by high temperatures.     

The Relationship Between Senescence and Ca2+-ATPase Activity of Microsomal Membrane and Lipid Peroxidation in Harvested Peach Fruit

Peach fruit easily soften and have a short storage time at normal temperature. In this study, peach fruit (Prunus persica sieb et Zucc cv. Yingqing) were picked and stored at 25 and 4℃ to investigate the senescence in correlation with Ca2+- ATPase activity of microsomal membrane and lipid peroxidation during ripening and senescence. In comparison with that stored at 25℃, the fruit stored at 4℃ exhibited a higher flesh firmness, lower respiration rate, and generated the late bigger peak value of Ca2+-ATPase activity as well as maintained the higher activity of the enzyme. Meanwhile, the lower levels of super oxygen radical (O2-) production and content of malondialdehyde (MDA), a product of membrane lipid peroxidation were observed. Sodium orthovanadate (SO) and erythrosin B (EB), as Ca2+-ATPase inhibitors, could stimulate the respiration rate. The results suggested that the slower senescence rate of peach fruit was closely related to the higher peak value and longer duration of Ca2+-ATPase activity in microsomal membrane, with the slighter membrane lipid peroxidation and lower O2(-) production rate.     

CaCl_2处理对采后柿果实生理变化的影响

以延津牛心柿为试材,对采收后的果实采用不同浓度的CaCl2处理,然后测定其软化衰老过程中果实硬度、可溶性固形物含量以及单宁含量的动态变化情况,结果表明:采后的柿果实用6%CaCl2处理能有效抑制其软化进程和单宁含量的降低,有效地延缓果实后熟和衰老进程。     

Changes of Activities in NAD Kinase and NADP Phosphatase During Ripening and Senescence of Tomato and Strawberry Fruits

Activities of NAD kinase(NADK)and NADP phosphatase and relationship between the two enzymes and temperature, respiration, ethylene production and trifluoperazine(TFP) were studied during ripening and senescence of strawberry and tomato frnits after harvest at 4℃and 20℃. The activity of NAD kinase in strawberry decreased slowly during first four days, then increased gradually. The NADP phosphatase activity increased at the second day, decreased the next day,then increased again. In tomato fruit, the activities of NAD kinase and NADP phosphatase increased at the second day, decreased with the ripening and senescence of the fruit. The change trend of NAD kinase and respiration in the two fruits were similar, the same were NADP phosphatase and ethylene production. TFP enhanced the activity of NAD kinase and had little effect on NADP phosphatase. Low temperature(4℃ ) activated the NAD kinase and reduced the activity of NADP phosphatase. These results indicated that the NAD kinase and NADP phosphatase were related to the ripening and senescence of strawberry and tomato fruits. The activation of NAD kinase probably postponed the ripening and senescence of the fruits.