桃果实采后生理生化及冷害研究进展

桃果实采后极易发生腐败变质现象,低温可延长果实的贮藏保鲜期,但长期的不适低温冷藏易使果实产生木质化、絮败、果肉褐变、果肉变红、糖酸比失调、固有芳香成分丧失或有害挥发性物质生成等品质劣变症状。不同类型桃果实甚至不同品种桃果实的采后品质劣变规律不同,低温的敏感度及冷害的发生时间点、综合表现特征亦有较大差异,其保鲜技术一直是国际上的难题。笔者对果实品质劣变发生的症状进行归纳,并从酶学、分子生物学和蛋白质组学等方面进行了相关机制阐释。建议对不同肉质类型桃采后生理特性和贮运特性进行系统性研究,制定相应的采后品质劣变调控技术,开发高效、安全的保鲜技术并应用于实践,为桃果实采后处理及保鲜贮运技术的应用提供一定的理论支撑。     

果胶酶和纤维素酶在桃果实成熟和絮败中的作用

 测定了果胶酶和纤维素酶在桃果实软化和絮败过程中的活性, 分析了贮前加温和中途加温的酶学效应。果实软化的启动似乎与PE、PG和纤维素酶活性的上升有关。endo-PG和纤维素酶活性与果实絮败程度之间呈显著负相关(r = - 0. 9408 , r = - 0. 9234) 。低温胁迫引起桃果实冷害絮败的本质是细胞壁果胶质的降解过程受阻。果胶质降解过程除了受到果胶酶的直接控制之外, 还受到纤维素酶的重要影响。中途加温或贮前加温减轻冷害的原因在于避免了低温胁迫对endo2PG和纤维素酶造成不可逆的伤害, 从而保证了果胶质降解过程的正常进行。     

采后桃果实酶促褐变机理的研究进展

桃是典型的呼吸跃变型果实,成熟于高温盛夏季节且采收后后熟迅速,一般采后5～7d就开始出现果肉褐变的现象,严重降低了果实的品质和经济价值。国内外对果实酶促褐变机理进行了广泛的研究,果实褐变现象主要是由多酚氧化酶(PPO)作用于天然底物酚类物质所导致的。通过文献分析,理清采后桃果实褐变的研究范畴和热点,本研究主要从采后酶促褐变机理、褐变底物、贮藏期间酚类底物含量的变化及延缓采后桃果实褐变的措施等方面进行了综述;发现采后桃果实褐变底物的化学结构鉴定研究缺乏系统的研究,今后仍需加强有关采后桃果肉酶促褐变底物种类及其化学结构鉴定、贮藏褐变期间酚类底物含量的变化趋势等方面的研究,为完善采后桃果实的酶促褐变机理提供理论依据。     

采前避雨栽培影响桃果实采后贮藏品质

【目的】桃果实的贮藏研究主要包括品质维持技术研发及调控机制分析,有关采前生产措施对于采后贮藏品质的报道相对较少。【方法】研究选取水蜜桃品种‘湖景蜜露’(Prunus persica L.Batsch‘Hujingmilu’)为材料,以露地栽培为对照,开展避雨栽培桃果实在采后低温贮藏及货架期间的品质分析。【结果】避雨栽培果实置于0℃贮藏21 d转货架3 d发生果肉组织褐变等冷害症状,对照果实出现冷害的时间为28 d转货架。不同栽培模式来源果实的蔗糖、果糖和葡萄糖等可溶性糖含量,以及苹果酸和柠檬酸等有机酸含量的显著差异主要发生在低温贮藏21 d转货架3 d,整个贮藏过程中的糖酸比含量在不同处理中并无显著差异。电子鼻的统计质量控制(SQC)分析结果显示,避雨栽培果实在采后低温贮藏期间与对照样品存在感官品质差异。顶空固相微萃取结合气质联用(SPME-GC-MS)分析发现低温后转货架发生冷害的避雨栽培果实内酯类、酯类、呋喃类和降异戊二烯等挥发性物质显著含量低于对照果实,冷害越严重浓度越低。对于具体挥发性物质而言,乙酸己酯、顺-3-乙酸己烯酯、反-2-乙酸己烯酯、γ-癸内酯等在避雨栽培果实低温贮藏转货架后显著低于对照。【结论】相对于露地栽培措施,避雨栽培桃果实在采后低温贮藏过程中更易发生冷害,主要症状包括果肉褐变、组织不能正常软化,蔗糖含量减少,果香型的内酯类和酯类物质含量下降。     

桃果实冷害机理及其防治措施研究进展

综述了桃果实在低温贮藏条件下冷害的症状与发生机理,从温度、气调、化学物质处理方面总结了冷害的防治措施,并提出以后研究的方向,为下一步研究提供参考。     

桃果实冷害相关蛋白的研究进展

低温是延长采后果实成熟衰老的有效手段,但是作为冷敏性的桃果实,不适宜低温贮藏容易发生冷害,失去商品价值。本文综述了近年来桃果实冷害发生过程相关蛋白的研究进展,主要包括细胞膜、细胞壁代谢相关蛋白以及一些信号蛋白,丰富桃果实采后贮藏保鲜的理论依据。在此基础上提出了目前仍需进一步研究的科学问题。     

桃果实采后生理研究综述

本文从桃果实采后呼吸作用和乙烯释放、膜质过氧化及活性氧代谢、果实软化及相关酶的作用、冷害生理、主要营养成分含量的变化等方面阐述了桃果实采后生理变化,旨在为提高桃果实贮藏保鲜效果提供参考。     

桃在低温贮藏过程中品质变化研究

为比较不同类型桃在低温条件下的贮藏特性,以水蜜桃‘美香’和蟠桃‘银河’为试材,研究了低温贮藏过程中果皮颜色、果实硬度、可溶性糖和有机酸含量等的变化。结果表明:低温贮藏期间桃果皮颜色的变化在不同品种间表现有较大差异,‘银河’在贮藏过程中果皮颜色略微加深;2个品种果实硬度总体下降比较明显;不同品种果实可溶性糖含量的变化比较复杂,其中果实可溶性糖总量波动较小,蔗糖含量在贮藏后期明显下降;有机酸总量方面,‘美香’和‘银河’总体都呈现前期下降,至贮藏后期小幅上升的变化趋势,其中柠檬酸的含量在贮藏后期出现明显下降。     

不同贮藏温度与采收期对‘秦超’桃果实品质的影响

以新品种‘秦超’桃为试材,研究不同贮藏温度与不同采收期对‘秦超’桃果实品质的影响,探索不同贮藏温度与不同采收期下果实品质的变化,为‘秦超’桃贮藏与采收提供实践指导。结果表明:常温下‘秦超’桃平均贮藏天数为21d,低温贮藏为58d。低温下能较好保持桃果实整个贮藏期间的果面色度、可溶性固形物含量,降低桃果实的失重率、腐烂率,明显延缓果肉硬度下降速率。在不同采收期间,随采收期延迟,‘秦超’桃果实单果质量不断增加,硬度、果面色度、可溶性固形物含量均能保持较好状态,成熟后树上挂果可延长30~40d。‘秦超’桃具有很好的贮藏性能,低温贮藏较常温贮藏可以有效保持‘秦超’桃的果实品质,延长果实品质的贮藏时间。延迟采收期,‘秦超’桃单果质量有大幅度增加,果实能够充分着色,提高果实外观品质。     

琯溪蜜柚果实采后有机酸代谢

以琯溪蜜柚果实为材料,测定了果实采后贮藏过程中的有机酸含量及相关代谢酶——柠檬酸合成酶(CS)、磷酸烯醇式丙酮酸羧化酶(PEPC)与细胞质乌头酸酶和NAD-异柠檬酸脱氢酶复合酶(NAD-IDH/Cyto-Aconitase)的活性,并探讨它们之间的相关性及有机酸的代谢机理。结果表明,1)琯溪蜜柚果实采后室温贮藏,果肉出现酸化,主要表现为柠檬酸含量大幅度增加,采后70 d达最高值,之后逐渐下降。相关分析表明,果实中的柠檬酸含量与CS活性呈极显著正相关,且与NAD-IDH/Cyto-Aconitase活性呈显著负相关。2)果实采后低温(6℃)贮藏,果实中的柠檬酸含量总体呈下降趋势,柠檬酸含量与PEPC活性呈极显著正相关。研究认为,CS、PEPC和NAD-IDH/Cyto-Aconitase是琯溪蜜柚果实采后有机酸积累的关键酶;果实采后低温(6℃)贮藏,可以较好地克服果实采后酸化的问题。     

Leatheriness and mealiness of peaches in relation to fruit maturity and storage temperature

Summary

`Huangjin' peaches (Prunus persica Batsch) were harvested at commercial harvest time (commercial) and 20 d before (early) or after (later) commercial harvest. Fruit from each harvest were stored at three temperature regimes (0, 5 and 10°C) at 95% r.h. After four weeks of storage at 0 or 5°C, early harvested fruit developed more leatheriness but less mealiness and later harvested fruit did not develop leatheriness but developed more mealiness comparedwith fruit from commercial harvest. Overall, fruit stored at 5°C developed more mealiness but less leatheriness than fruitat 0°C for the same period of storage. When stored at 10°C for two weeks, after which fruit were senescent, fruit did not develop any leatheriness or mealiness regardless of harvest times. Fruit with leatheriness were firmer (>30 N) thanjuicy or mealy fruit (<10 N) after the same period of cold storage and 4 d at 20°C. Mealy fruit were as soft as juicy fruit. 1-Aminocyclopropane-1-carboxylate oxidase (ACO) activity, 1-aminocyclopropane-1-carboxylic acid (ACC) content, and polygalacturonase (PG) and galactosidase (GAL) activities were lower, and insoluble pectin content was higher in leathery fruit than that in juicy or mealy fruit. ACO, PG and GAL activity, ACC, and insoluble pectin content were similar between mealy and juicy fruit.     

Intermittent warming of peaches reduces chilling injury by enhancing ethylene production and enzymes mediated by ethylene

SUMMARY

Peaches (Prunus persica ‘Hermoza’) were ripened at 208>C after harvest and either stored at 08C for four weeks (control) to induce chilling injury or given intermittent warming (IW) on the twelfth day of storage (28C for 24.h) to alleviate chilling injury (CI). Continuously stored fruit from control developed wo olliness, a CI disorder, during ripening at 208C after cold storage while only a small percentage of IW fruit developed woolliness. CI fruit produced less ethylene during ripening after storage, and this inhibited ethylene production was closely tied with woolliness development. The IW treatment caused enhanced ethylene production in the fruit when returned to 08C and the ethylene remained higher than control fruit until the end of the storage period. IW also induced the messages for 1-aminocyclopropane-1-carboxylic acid oxidase (ACO) and 1-aminocyclopropane-1-carboxylic acid synthase (ACS) in the ethylene synthesis pathway. IW also elevated the mRNA of the cell wall degrading enzymes polygalacturonase (PG) and endo-1,4-gluconase (EGase). The mRNAs of the cell wall enzymes and the enzymes in the ethylene synthesis pathway remained higher even after 5.d at 08 C following the IW treatment. It is suggested that IW maintained the fruit tissue capacity to ripen normally by preventing inhibition of the ethylene synthesis pathway which occurred in the control fruit after extended storage.     

园艺作物果形遗传研究进展

 果实形状是果品、瓜菜及果菜类蔬菜等园艺作物品质评价、分类以及市场定级的主要考核指标之一,也是商业品质育种的重要依据。对园艺作物果形遗传分析研究中的果形测定方法、遗传分析方法及主要园艺作物果形遗传等进行了综述,并对主要园艺作物果形QTL定位及基因定位和克隆的研究进展作了重点阐述。     

鲜枣贮藏期病害研究进展

对鲜枣采后贮藏期间发生的生理性病害和侵染性病害进行了概述。贮藏期易发生的生理性病害主要包括枣果的酒化、褐变和低温伤害;病原菌在田间的潜伏侵染和采后的伤口侵染是引起枣果贮藏病害的主要原因,其病原菌的种类既有真菌也有细菌。枣果病原菌潜伏侵染的病理机制是今后侵染性病害的研究热点。减少枣果的采后病害可以通过田间综合防治、采收及采后处理过程中避免机械损伤和入库前的消毒处理等措施来解决。生物防治是控制枣果采后病害的研究新方向。     

果实品质无损伤检测研究进展

现代检测设备和分析软件的快速发展加快了果实检测技术的发展。在总结果实品质常规检测方法的基础上,综述了无损伤检测技术在果品生产和科研中的应用进展。根据测试原理不同,包括机器视觉技术测定果实颜色、形状、大小,近红外光谱技术测定果实可溶性固形物含量,力学和声学技术测定果实质地,电化学技术测定果实香气和成熟度,利用电学特性测定果实成熟衰老,核磁共振/磁共振成像技术测定内部病变等。还报道了这些技术在其他方面如干物质含量、酸度、含水率、生理病害、衰老等检测中的应用。并注重商业化生产中仪器装备在线应用情况。最后提出应注意问题并对应用前景进行展望。     

Partial rootzone drying maintains fruit quality of ‘Golden Delicious’ apples at harvest and postharvest

Partial rootzone drying (PRD) has been evaluated at harvest, but its effects on apple fruit postharvest life is little known for apples grown in semi-arid regions. The objective of this study was to test the hypothesis that water savings via PRD may affect fruit quality at harvest and postharvest-life of ‘Golden Delicious’ apples grown in a semi-arid region. The experiment was conducted from 2005 to 2007. The irrigation treatments were commercial irrigation as control (CI) and PRD. After 3 years of evaluation, fruit quality at harvest, measured as fruit weight, flesh firmness, and total soluble solids concentration, was similar between CI fruit and PRD fruit. Dry matter concentration (DMC) was higher in PRD fruit than in CI fruit in 2005. The fruit quality after 18 days storage at room temperature (13–18 °C and 51–56% relative humidity) was similar between CI fruit and PRD fruit. The DMC was the highest in PRD fruit in the 2005 and 2007 growing seasons, and tended to be higher in PRD fruit than in CI fruit in 2006. Total soluble solids concentration was ≈8.7% higher in PRD fruit than in CI fruit in 2007. Fruit weight loss was similar between treatments. This study suggests that water deficit via PRD did not damage fruit quality at harvest or after storage at room temperature. Additionally, PRD irrigation saved about 3240 m³ of water per hectare. Therefore, PRD can be recommended for commercial use in semi-arid regions and to those growers interested in either long-term storage or distant markets.     

Bioherbicide Research: Defining Success (A Tribute to RaghavanCharudattan)

Summary

Corky tissue (CT) is a major disorder affecting the fruit of sapota (Manilkara achras) ‘Cricket Ball’ in India. Affected fruit have a hard lump in the pulp and dry acidic flesh, but have no external symptoms. The main objective of the present study was to investigate the role of seed in the disorder. Treating fruit with 1.0 g l^–1 gibberellic acid (GA₃) at 50% maturity increased fruit fresh weight and presumably seed growth, and reduced the incidence of CT compared with that in untreated control fruit. In contrast, fruit treated with 3.0 g l^–1 paclobutrazol (PBZ) showed the opposite response. Fruit treated at 70% or 90% maturity gave no response, suggesting that poor seed viability during the early stage of fruit development was associated with CT. Seed stored for 30 d under ambient conditions lost water and had lower viability. There were decreases in the moisture content and calcium concentration in seed and pulp as the severity of CT increased in fruit harvested in the field, indicating a “reverse flow” of water and nutrients from the fruit. It is proposed that the incidence of CT is related to reduced seed viability and the consequent losses of water and calcium from fruit due to competition for resources with the rest of the tree. Further studies are required to assess the potential of the application of GA₃ to reduce the incidence of CT in commercial orchards.     

苹果水心病无损检测与防治研究进展

苹果水心病是一种果实生理病害,在所有苹果的栽培生长区域均有发生。品种、果实成熟度、温度、栽培条件、果实大小、矿质营养、贮藏条件等因素影响苹果水心病的发生。目前其无损检测的主要方法有光密度法、X-射线法、质量密度法和磁共振影像法。补充钙素营养、增施有机肥、适时采收、合理修剪等是防治苹果水心病的关键措施。     

Water relations,growth, yield,and fruit quality of hot pepper under deficit irrigation and partial rootzone drying

We compared two water-saving irrigation practices, deficit irrigation (DI) and partial rootzone drying (PRD), for their effects on growth and quality of ‘Ancho St. Luis’ hot pepper (Capsicum annum L.). The treatments were: commercial irrigation (CI) considered as the control, irrigating both sides of the rootzone with half of the volume of CI considered as DI, and alternating irrigation between two sides of the rootzone with half the volume of CI at each irrigation time considered as PRD. Midday leaf water potentials of PRD and DI plants were lower by 0.15 and 0.30 MPa, respectively, than of CI plants from 130 days after sowing. Total fresh mass of fruit was reduced by 19 and 34.7% in PRD and DI, respectively, compared to CI. Fruit number per plant was reduced by more than 20% in PRD and DI compared to CI. Total dry mass of fruit was similar among the treatments. At harvest, DI fruit had 21% higher total soluble solids concentration and better colour development than other treatments. Although incidence of blossom-end rot was high in PRD and DI fruit, more than 80% of fruit from PRD was not affected. DI and PRD saved 170 and 164 l of water, respectively, compared to CI and they could be feasible irrigation strategies for hot pepper production where the benefit from saving water outweighs the decrease in total fresh mass of fruit.     

桃小食心虫发生规律及防控技术研究进展

桃小食心虫是我国果树上主要的蛀果害虫,文章主要综述桃小食心虫发生、发育特点和综合防控技术,寻求桃小食心虫的进一步研究方向和探讨新的防治途径