Chilling-injury in cucumber fruits. II. Chemical analyses of leakage substances and anatomical observation of symptoms

From the chemical composition of leakage substances, it was concluded that there was greater leakage of micro-molecule components in cucumber fruits which had been chilled to 0°C than in fruit chilled to 5°C. However, leakage of macro-molecule components was greater in the 5°C fruit than in the 0°C fruit with longer periods of storage. These results suggest that the plasmalemma develops leakage in the 0°C fruit, whereas there is membrane breakage in the 5°C fruit.Microscopic observations support this assumption.     

Chilling-injury in cucumber fruits. VI. The mechanism of pectin de-methylation

By incubating the homogenate of cucumber fruits in vitro, pectin de-methylation was considerably accelerated especially at near neutral pH. Histo-chemical observations based on detection of SH-protein present in sieve tubes, revealed that the cell walls of the fruits chilled at 0°C for 3 days contained the tube constituents, in which pectinmethylesterase was also found. The esterase of the tubes was cold-labile. All the esterases present in a fruit were activated by an addition of ascorbic acid, a reducing agent.The set of these results, together with our previous papers, suggests that in cucumber fruits chilling may at first break the plasmalemma of sieve tubes, whose exudate outflows into the cell walls of tissue cells. The subsequent contact between the tube esterase and wall pectin results in the pectin de-methylation, which makes elastic cell walls rigid and fragile. This ultimately leads to occurrence of water-stress injury. A decrease of redox potential in the chilled fruits may serve for raising the activity of the cold-labile tube esterase.     

Chilling-injury in cucumber fruits. IV. The analogy between osmotic-stress injury and chilling-injury

At warm temperatures, young cucumber fruit with rigid cell walls was found to suffer osmotic-stress injury when hydrated or dehydrated. The osmotic-stress injury of hydrated fruit was similar to chilling-injury of cucumber fruit stored at 5°C, whereas the stress injury of dehydrated young fruit appeared similar to injury of fruit chilled to 0°C. In contrast, adult fruit, with soft cell walls, did not develop osmotic-stress injury.On the basis of these results, together with previous reports, it is proposed that cell wall rigidity and water stress in the fruit are the direct causes of chilling-injury.     

Chilling-injury in cucumbers. V. Polysaccharide changes in cell walls

A decline in the hot-water-soluble pectin and an increase in the hot-water-insoluble pectin were observed when cucumber fruits were subjected to chilling temperatures. Infrared absorption spectra revealed the presence of highly esterified carboxyl groups in the soluble pectin, and of free carboxyl groups in the insoluble pectin. An increase of the insoluble pectin during chilling was also found in other chilling-sensitive plants. From these results it is suggested that a de-esterification of pectin and the concomitant increase of polymeric pectin takes place during chilling, making cell walls firmer, and that these pectic changes may be a characteristic common to a number of chilling-sensitive plants.     

江石榴果实贮藏期生理变化研究

对江石榴果实在(10±0.5)、(5±0.5)℃贮藏条件下生理变化和和贮藏效果进行了研究。结果表明:江石榴属非跃变型果实,果实乙烯释放量较低;随果实衰老,相对电导率及丙二醛含量缓慢增加,可滴定酸含量和可溶性固形物含量变化不显著;与在10℃贮藏相比,在5℃贮藏减少了果实的褐变和腐烂程度,贮藏16周后,商品果率达80%。     

Effect of parthenocarpy,peeling and fruit age on the changes in volume and specific gravity of cucumber fruits during storage at 20°C

Either parthenocarpically grown, peeled or at any stage of picking, cucumber fruits showed a tendency to increase in volume and decrease in specific gravity while they were stored under unsaturated vapour pressure at 20°C. The amount of change varied according to the treatment.Recovery from a flaccid appearance occurred in all fruit except very young ones. In those fruits the incipient recovery from wilting, an increase in volume and a decrease in specific gravity, coincided.Parthenocarpic fruits showed an increase in volume at almost the same rate in any transverse quarter of a fruit, in contrast to the pollinated ones in which the most distal quarter enlarged more than the other parts. Pithy appearance of the fruit wall was evenly distributed through a parthenocarpic fruit to a moderate degree, but at the proximal half of a pollinated one it was severe.     

外源褪黑素处理对常温货架期梨果实贮藏品质的影响

【目的】明确褪黑素处理对采后常温货架期梨果实贮藏品质的影响。【方法】以新梨7号果实为试材,设置50、100、150、200、250μmol·L^-15个褪黑素浓度梯度处理,以清水处理为对照,测定了常温货架期果实失重率、硬度、可溶性固形物含量、乙烯释放速率、香气物质种类和含量等指标。【结果】从处理后5、10、15和20 d的测定结果可以看出,与对照相比,褪黑素处理减少了梨果实内水分的消耗,果实的失重率升高的幅度小,果实硬度较高,150μmol·L^-1褪黑素处理失重率和果实硬度与对照差异达显著水平;褪黑素处理能够使新梨7号果实的可溶性固形物含量稳定,处理20 d时,不同浓度褪黑素处理可溶性固形物含量显著高于对照;褪黑素处理新梨7号果实的乙烯释放速率均低于对照,以150μmol·L^-1褪黑素处理最低,较对照减少了87.05%,差异显著;不同浓度褪黑素处理对新梨7号果实香气物质种类和含量存在差异,褪黑素处理能调节果实香气种类和含量。【结论】外源褪黑素处理可延缓新梨7号梨果实失水,保持果实硬度和可溶性固形物含量,减少乙烯释放。适宜浓度褪黑素处理可调节香气物质的种类和含量,保证常温货架期贮藏品质,综合认为,150μmol·L^-1浓度褪黑素处理能够有效延缓梨果实的衰老,处理效果最好。     

高温短时热空气处理对枇杷品质和冷害的影响

为了研究高温短时热空气处理对枇杷果实冷害和品质的影响,采用45℃热空气2、3、4 h处理采后枇杷（解放钟）果实,分析冷藏（5℃）期间其品质和相关生理指标的变化。结果表明,经45℃3 h热处理的果实冷藏后品质最佳,冷害最轻。该处理能显著降低果实失重率、硬度和果皮难剥离程度的上升,保持较高的果肉出汁率;提高果实冷藏期间超氧...     

不同温度对黄瓜种子发芽的影响及耐热性比较

为了筛选出种子发芽耐热性强的黄瓜品种,将不同类型黄瓜品种的种子置于28、38和42℃条件下进行发芽试验,比较种子的发芽能力。结果表明:不同类型的黄瓜品种在不同的温度下发芽能力存在明显差异,其中西双版纳黄瓜、Poinsett97、北京截头种子发芽耐热能力明显强于HH1-8-57和二早子。     

The effect of temperature on certain chemical changes and the storage behaviour of jujube fruits (Zizyphus spinachristi (L.), Willd.)

Summary

Jujube fruits (Zizyphus spinachristi (L.) Willd.) cv. Bambawi were harvested at the mature green stage and stored at 10°C and 27–30°C. Titratable acidity and total chlorophyll decreased as the fruit matured, the rate of decline being more rapid at the higher temperature. Total soluble solids, carotenoids and ascorbic acid contents of the fruit increased towards maturity, the increase being faster at the higher temperature. Jujube fruits could be stored for six days at room temperature and twenty-five days under refrigeration at 10°C.     

Effects of high-humidity storage on quality,decay and storage life of cherry,lemon and peach fruits

Sweet cherries (Prunus avium (L.) ‘Lambert’ and ‘Blackboy’), lemons (Citrus limon (L.) Burm. f. ‘Lisbon’) and peaches (Prunus persica (L.) Batsch, ‘Summerset’) were stored at 77–83, 90–94 and 95–99% RH (high humidity) at near-optimal storage temperatures after harvest and treatment with fungicides. High-humidity storage did not increase the storage life of peaches held at 0°C, but the life expectancy of cherries (both cultivars) was extended by 7–10 days at 0°C, and of lemons by at least 4 weeks at 10°C when fruit were stored at 95–99% RH compared with levels below 95%. The beneficial effects of high humidity were attributed to retardation of peel desiccation and associated reductions in fruit deformation, peel de-greening, chilling-injury and decay in lemons and to the maintenance of a fresher stalk and a firmer, less shrivelled fruit in cherries. High humidity had no effect on decay in cherries or peaches, but it significantly reduced weight loss and delayed the appearance of shrivel in peaches stored at 0°C. However, after storage at high humidity for 4 weeks, peaches ripened with low rates of C₂H₄ evolution and showed severe low-temperature injury, slight peeling-injury and a poor flavour ex-store.     

Effect of storage temperature on ripening and quality of custard apple (Annona squamosa L.) fruits

Summary

The effect of storage temperature on ripening, shelf life and chemical composition of custard apple (Annona squamosa L.) fruits stored at 10,15,20 and 25°C was studied. The safe range of storage temperature was found to be between 15 and 20°C, with maximum shelf life at 15°C. The ripening of fruits was observed on days 4, 6 and 9 of storage at 25,20, and 15°C respectively. The colour of the pulp, texture, taste and flavour of ripe fruits held at 25 and 20°C were superior followed by fruits stored at 15°C. At 10°C, the fruits became hard with surface blackening, messy pulp and less sweetness. The major changes during ripening were a continuous decrease in fruit firmness and starch content and a continuous increase in TSS and sugars, the changes being more rapid at 25 and 20°C than at 15 and 10°C. The acidity and ascorbic acid contents increased slightly during the initial stages of ripening followed by a decline, in the fruits stored at different temperatures. Custard apple fruits stored at 25 and 20^CC had a clear climacteric peak whereas those stored at 15 and 10°C did not show any distinct rise in respiration rate. Ethylene peak (2.40 µl kg^–1 h^–1) coincided with the respiratory climacteric at 25^CC storage, corresponding with the peaks in TSS, sugars, ascorbic acid and acidity.     

MA贮藏对尖柿硬度及相关生理变化的影响

研究了在低温条件下,MA贮藏方式对柿硬度及相关生理变化的影响。结果表明:MA贮藏对于减缓柿的软化具有十分显著的作用,贮藏96d,处理果硬度是对照果硬度的3倍,贮藏120d后,处理果仍有一定的硬度,但对照果已完全软化腐烂;MA贮藏降低了柿的呼吸速率及乙烯释放量,并抑制PG、Cx活性升高和果胶、纤维素的降解;同时MA贮藏对于果实的蒸腾失水也有显著的抑制作用。     

Controlled-atmosphere storage of kiwifruit. I. Effect on fruit firmness and storage life

The effect of atmospheres containing high CO₂ and low O₂ on the firmness of kiwifruit (Actinidia chinensis Planch.) during cool storage at 0°C has been studied. Atmospheres containing above 4% CO₂ with 15–20%O₂ caused a retardation in the softening of kiwifruit. This effect increased as the CO₂ content of the atmosphere increased from 4 to 10%, but additional CO₂ above 10% had no further effect on fruit firmness. Low O₂ (2–3%) with 3–5% CO₂ further delayed the rate of kiwifruit softening and increased storage life up to 3–4 months beyond normal air-storage life. Although controlled-atmosphere storage increases storage life of kiwifruit, the magnitude of the effect was found to vary from year to year. Contamination of the storage atmosphere by as little as 0.1 μl^?1 ethylene severely reduced the effectiveness of controlled-atmosphere storage in maintaining kiwifruit firmness, even at 0°C.     

Cuticular cracking in pepper fruit. I. Effects of night temperature and humidity

Summary

The objective of the present study was to characterize some of the anatomical and physiological characteristics of fruit cracking in bell pepper (Capsicum annuum L.). Scanning-electron micrographs show that initiation of fruit cracking in bell pepper is by formation of mini-cracks on the cuticle layer; these then enlarge into cracks and traverse the epidermal cells. Pepper cultivars differ in their sensitivity to cracking, partly because of differences in fruit pericarp thickness. Limitation of night transpiration by high humidity or low temperature increased the turgor potential of the fruit pericarp and enhanced cracking. Likewise, leaf pruning suppressed night transpiration and concomitantly increased cracking. Fruit cuticle transpiration was found to be low in the early stages of fruit development and to increase as the fruit became susceptible to cracking. Environmental conditions which enhanced cracking also increased cuticle transpiration in a sensitive pepper cultivar but not in a less sensitive one. We suggest that fruit cracking in bell pepper occurs because reduction in night transpiration causes high turgor pressure in the fruit. As the cuticle becomes permeable to water, the inner turgor pressure causes the cuticle to crack. Differences in cultivar sensitivity may be partly due to differences in pericarp thickness and cuticle properties, but additional factors may be involved.     

低温胁迫下油菜素内酯对黄瓜种子萌发及幼苗生长的影响

以耐冷型黄瓜品种'RT-5'和冷敏型黄瓜品种'W-108'种子为试验材料,采用2,4-表油菜素内酯(EBR)浸泡法和添加法处理,研究了15℃低温胁迫下不同质量浓度(0.001、0.010、0.100、1.000mg·L~(-1))EBR对黄瓜种子萌发及幼苗生长的影响。结果表明,适当质量浓度的(0.001～0.100 mg·L~(-1))EBR处理可以提高黄瓜种子的发芽势、发芽率、胚轴长、轴根比和侧根数,减轻种子萌发和幼苗受到的低温伤害,且冷敏品种'W-108'的低温缓解效应大于耐冷品种'RT-5'。高质量浓度(1.000 mg·L~(-1))EBR则显著抑制黄瓜种子萌发和幼苗生长。各浓度EBR处理均不同程度降低了黄瓜幼苗的胚根长,随EBR浓度升高,抑制作用加强。运用隶属函数法对EBR各处理进行综合评价,结果表明EBR浸泡法处理效果优于添加法,其中以浸泡法0.010 mg·L~(-1) EBR处理对低温胁迫下黄瓜种子萌发及幼苗生长的促进效果最好。     

The effect of storage temperature on quality and decay percentage of ‘Pairi’ and ‘Taimour’ mango fruits

The effects of storage temperatures, especially chilling-temperatures, and the duration of exposure to them, on quality and decay percentage, and on the shelf-life of ‘Pairi’ and ‘Taimour’ mango fruits were studied. ‘Taimour’ fruits had better keeping-quality, storage ability and a longer marketing period than ‘Pairi’ fruits under all storage temperatures. Both cultivars were affected by storing at 0 °C and the severity of chilling was proportional to the duration of cold storage. ‘Taimour’ fruits were less sensitive to chilling-injury than ‘Pairi’ fruits. Storage at 5 °C or slightly higher was the most suitable temperature for both cultivars, followed by 10 °C.     

Effect of different temperatures on the storage of papaya fruits and respirational activity during storage

Mature papaya fruits were stored at 10 and 15°C to study the effect of these temperatures on the storage and of respirational activity during storage. Percentage weight loss of fruits increased with prolonged storage period, and the increase was greater in fruits stored at 15 than at 10°C. The decay percentage was greater at the higher temperature than at the lower temperature. Total soluble solids showed a slight and gradual increase upto the end of the storage period. The high storage temperature accelerated colour development in the peel and total chlorophyll diminished. There was an increase in total carotenoids in both the peel and the pulp as the storage period increased, and the rate of increase was greater at the higher temperature.The respiration rate was relatively low at the beginning of ripening and tended to level off until the 11th and 12th day of storage, which were followed by a striking increase until it reached its maximum rate at the over ripe stage.     

高温下丝瓜砧木对嫁接黄瓜生长、产量及果实品质的影响

为了探究嫁接对黄瓜生长、产量及果实品质的影响,将荷兰型短黄瓜‘春秋王2号’嫁接到‘五叶香’丝瓜砧木上,对植株田间生长、发病情况及后期产量、品质进行了测定。结果表明,移栽后的丝瓜嫁接苗在各时期测定的植株高度、茎粗度、叶片数、叶面积及净光合速率(Pn)都大于黄瓜自根砧嫁接苗,且病毒病发病率低,始花期比自根砧嫁接苗提早6 d,早期产量也较自根砧嫁接苗高,但后期增产不明显;果实中维生素C及可溶性蛋白含量与自根砧嫁接苗相差不大,可溶性糖含量显著降低,但游离氨基酸含量显著升高,说明以‘五叶香‘丝瓜为砧木嫁接黄瓜,在一定程度上能提高高温季节下黄瓜的产量,且该嫁接使得果实中游离氨基酸含量增加,提高了黄瓜的营养价值。     

贮藏温度和湿度对丰水梨花粉生活力的影响

研究贮藏温度和湿度对丰水梨花粉萌发率和花粉管生长的影响。结果表明,在室温下贮藏15天,花粉生活力迅速下降;在4℃贮藏90天,花粉生活力下降缓慢,萌发率降为33·4%;在-20、-73、-196℃贮藏540天,花粉生活力下降极慢,其中-196℃处理,贮藏花粉萌发率为68·37%,-73℃处理,花粉萌发率为62·86%,-20℃处理,花粉萌发率为42·15%。