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.     

Studies on keeping-quality of vegetables and fruits. III. Changes in sugar and organic acid contents accompanying the chilling-injury of eggplant fruits

The mechanism of chiiling-injury in fruits of eggplants (Solanum melongena L. cultivar ‘Hyonaga’) was investigated by determining the sugar and organic acid content during cold storage and after exposure to low temperature for various periods. Fructose, glucose and maltose were detected, and totalled more than 96% of total sugar on the initial day. Total sugar content increased to 30% higher than the initial day after 2 days of cold storage, and after that decreased gradually, while in 20° C-stored fruits it decreased sharply. Fructose, glucose and maltose increased rapidly after transfer from 1° C to 20° C. Succinic, oxalic, malic and citric acid were detected before storage. Malic and citric acid were found to be the main organic acids. The ratio of malic/citric acid in fruits stored at 1°C decreased during storage, while after storage at 20°C it increased. The ratio in fruits after transfer from 1°C to 20°C increased rapidly during the time course. The ratio of malic/citric acid ranged from 6.0 to 6.8 in healthy fruits, while it was below 5.9 or above 7.3 in chilled fruits. It is suggested that according to this ratio the degree of chilling-injury of eggplant fruits might be foreseen.     

A novel postharvest UV-C treatment to reduce chilling injury (membrane damage,browning and chlorophyll degradation) in banana peel

To investigate the mode of action of UV-C to alleviate CI in banana. Banana [Musa (AAA group), Cavendish subgroup cv. Cavendish] fruits were treated with UV-C at dosages of 0.03 kJ m⁻² prior to storage at 8 or 25 °C. UV-C treatment reduced both the incidence and severity of banana fruits stored under low temperature. UV-C treatment reduced membrane damage indicated by lower activity of lipoxygenase (LOX) and malondialdehyde (MDA) content. In additions, the in vitro polyphenol oxidase (PPO) activity was activated when fruits were stored at CI temperature and UV-C treatment could inhibit the PPO activity. UV-C treatment also delayed yellowing and chlorophyll (Chl) degradation due to the inhibition of chlorophyllase and chl-degrading peroxidase activities. Furthermore, the reduction of ethylene production and respiration rate by UV-C treatment results in extended postharvest shelf life of banana. These finding suggest that the loss of cellular compartments in consequence of membrane degradation, combined with the increase of PPO activity, might contribute to the development of CI in banana peel. UV-C treatment may play an important role in maintained membrane integrity and inhibited PPO activity, reducing the severity of CI symptom and delayed ripening in banana. This novel technique may offer an advance in postharvest handling of bananas and other chilling-sensitive commodities in order to reduce postharvest losses resulting from CI.     

Chilling-injury in cucumber fruits. I. Effects of storage temperature on symptoms and physiological changes

Cucumber fruits transferred to a warm temperature after chilling displayed various symptoms of chilling-injury. In cucumbers chilled to 0°C, vertical fine wrinkles and/or shallow pitting was observed, while after chilling to 5°C deep pitting and/or surface depressions were apparent. Moreover, in the 0°C fruit compared with 5°C fruit, a higher $\text{210}\text{264}$ mμ UV absorption ratio of leakage substances during chilling was observed. These results suggest that the causes of chilling-injury in the 0°C and 5°C fruit are distinct from one another. Weight loss after chilling, the amount of leakage substances, the exudate content from the cut surface of the fruit, redox potential, titratable acidity and respiratory activity were also checked after periods of chilling of 3 to 15 days.     

香蕉果皮2个HSP70基因片段的克隆及其在热激和冷藏过程中的表达

温度逆境胁迫可以诱导热激蛋白的表达,而热激处理能够减轻果实冷害。为了探讨温度逆境对香蕉热激蛋白基因表达的调控、辨析香蕉热激蛋白基因的表达与果实冷害的关系,采用同源序列法分离了香蕉果皮HSP70基因序列-根据已经报道的HSP70基因的氨基酸保守序列设计引物、以香蕉果皮总RNA为模板,用RT-PCR方法克隆香蕉的HSP70 cDNA,Northern杂交分析该基因在不同贮藏温度下的表达特征。结果得到2个序列不同的HSP70基因片段,分别命名为Ma-HSP70-1和Ma-HSP70-2,Ma-HSP70-1和Ma-HSP70-2之间的碱基同源性为86.9%,氨基酸同源性为97.1%。Northern杂交的结果表明,38℃短期热激处理诱导了Ma-HSP70-2基因的表达,低温冷藏能使2个基因的表达增强。并初步认为Ma-HSP70可能与香蕉果实耐冷性有关。     

香蕉果实贮藏冷害与NAD激酶活性变化的关系

 以‘巴西'香蕉果实为试材,研究了果实采后在22℃和6℃下贮藏期间NAD激酶(NADK)活性与冷害发生情况,膜渗透性,丙二醛(MDA)含量,多酚氧化酶(PPO)以及苯丙氨酸解氨酶(PAL)活性变化的关系。结果表明,6℃下贮藏3d 时果实出现冷害症状, 11d时冷害加重,同时NAD激酶活性、膜渗透性、MDA含量和PPO活性均始终高于22℃贮藏的, 并在11d时达到高峰,而PAL活性则呈下降趋势,其活性始终低于22℃贮藏的。6℃下用NAD激酶激活剂氯化钙处理香蕉果实后,NADK受到激活,冷害程度加重,而用钙离子通道阻塞剂异博定（verapamil,Vp）处理后则抑制了NADK 活性,果实冷害症状延迟4 d 出现,冷害程度减弱,说明香蕉果实冷害发生与NADK 活性变化密切相关。     

Low temperature induce differential expression genes in banana fruits

Differential display was used to identify gene expression of banana fruit in response to low temperature stress. Banana fruits were kept at 10 °C for 8 h and 60 differential expressed fragments in pulp and peel were obtained. These fragments had an average size of 200 pb or greater and Dot blotting hybridization as well as Northern blot corroborated specific expression of these differential expressed fragments. Among the several differentially expressed genes, we found genes involved in response to pathogen attack, wounding and a ripening-associated gene. We consider these genes to belong to a general pathway which is activated upon general stress signaling.     

Effect of different storage temperatures on phenolic compounds in banana and mango fruits

The general trend of changes in total phenolic compounds of pulp banana fruits harvested at the mature-green stage was a decrease during storage. The higher the storage temperature, the more rapid was the loss in total phenols. The peels lost their total phenols very rapidly and this loss was proportional to the duration of storage at 0°C. There was an inverse relationship between total phenols content and the degree of blackening during storage at injurious chilling temperatures. Concerning the change of phenolic compounds in mango fruits, the skin of ‘Pairi’ mango contained very considerably more total phenolic compounds than the flesh and this content tended to decrease with duration of storage.     

香蕉和大蕉果实在不同温度下催熟后的色泽变化

 香蕉和大蕉在20℃和30℃条件下果实催熟期间果皮色泽及几种色素含量的变化结果表明: 在20℃下香蕉、大蕉具有正常的呼吸和乙烯释放高峰, 果皮色泽由绿转黄, 叶绿素含量逐渐降低, 类胡萝卜素含量逐渐上升; 但在30℃下, 香蕉果实虽然出现了正常的呼吸和乙烯释放的高峰, 但叶绿素的降解受到了一定的抑制, 果皮不能正常褪绿, 出现了青皮熟现象, 而大蕉却能正常褪绿转黄。     

过氧化氢在采后香蕉果实耐冷性诱导中的作用

采用外源过氧化氢（H₂O₂）、能诱导植物产生内源H₂O₂的茉莉酸甲酯（MJ）和水杨酸（SA）处理采后香蕉果实,探讨H₂O₂在采后香蕉果实耐冷诱导中的作用,结果表明：在7℃下贮藏,外源20 mmol·L^-1 H₂O₂、0.7 mmol·L^-1 SA、0.1mmol·L^-1 MJ处理能使果实冷害症状推迟2～5d出现;处理还延缓了香蕉果皮细胞膜透性和MDA含量的增加,提高了超氧化物歧化酶（SOD）和过氧化物酶（POD）活性,抑制了过氧化氢酶（CAT）活性,从而导致香蕉果皮H₂O₂积累。推测H₂O₂可能作为信号分子参与诱导了采后香蕉果实的抗冷性。     

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.     

基于VAR模型的北京市西瓜市场的替代与整合

西瓜是我国重要的鲜活农产品之一。利用北京市批发市场中香蕉、梨子、哈密瓜、菠萝4种典型水果的价格数据,建立向量自回归模型探究香蕉、梨子、哈密瓜、菠萝4种水果在水果市场对西瓜的替代作用和动态影响,进而分析各种水果对西瓜的替代效果与水果市场的整合效应。结果表明:在不考虑季节因素的影响时,哈密瓜、香蕉、梨子与西瓜之间存在着较强的替代关系,强弱依次为哈密瓜>香蕉>梨子,而菠萝对西瓜不具有明显的替代作用。当价格受到正向的外部冲击时,西瓜自身价格会上涨,以分担这种压力,哈密瓜、香蕉和梨子这些存在替代关系的水果对西瓜价格分担上涨压力的贡献率比没有替代关系的水果高。在推动北京市西瓜市场发展的同时也要顾全整体水果市场的大局,充分考虑到各种水果之间的相互影响的替代关系。     

延长黄熟香蕉货架期的研究

实验研究了热水处理、包装自发气调(MAP)、乙烯吸收剂、1-甲基环丙烯(1-MCP)、贮藏温度、多菌灵等对黄熟香蕉货架期的影响。对香蕉的有机酸和总可溶性固形物含量、色差值、包装袋内的CO2浓度进行了测定。结果显示:在(28±2)℃贮藏条件下,黄熟香蕉的货架期只有1d。1-MCP延长黄熟香蕉货架期效果最好,可以延长4d;10%CO2和2%O2的MAP气调和乙烯吸收剂可延长货架期1d;500mg/kg多菌灵48℃热处理浸泡香蕉30s,延长货架期1d。50℃以上高温预处理15min,引起黄熟香蕉热害;pH4.5酸性溶液48℃浸15min,也有明显伤害。48℃高温预处理15min,没有引起伤害。黄熟香蕉对冷害敏感。应用500mg/kg多菌灵浸果30s,晾干后放入0.04mm厚聚乙烯袋内,放入0.8%乙烯吸收剂,换气后初始CO2为10%,O2为2%,袋内注射1-MCP,使最终浓度达0.13mmol/L,可使黄熟香蕉货架期由原来的1d延长到6d。     

低温和多效唑对香蕉及大蕉超氧物歧化酶和脱落酸的影响

低温胁迫处理引起香蕉和大蕉超氧物歧化酶（ＳＯＤ）活性的下降，香蕉下降的幅度比大蕉大。大蕉在低温胁迫下脱落酸（ＡＢＡ）含量增加，而香蕉ＡＢＡ含量明显低于大蕉，并在低温胁迫过程中出现波动。多效唑处理可以提高香蕉的抗冷性，低温胁迫条件下处理香蕉比对照的香蕉具有较高ＳＯＤ活性和内源ＡＢＡ含量。香蕉和大蕉ＳＯＤ同工酶谱带组成在低温前后没有变化，但香蕉谱带中多数强度有所改变，其中同工酶Ｖ强度明显加强，大蕉ＳＯＤ同工酶则相对较稳定。     

香蕉GLP基因家族全基因组鉴定及表达分析

为揭示香蕉类萌发素蛋白（GLP）功能,对香蕉GLP基因家族（MaGLP）进行了全基因组鉴定,分析了基因结构、染色体分布和启动子顺式作用元件和转录因子结合位点（TFBS）分布情况以及编码蛋白的理化性质、保守基序、进化关系,同时基于转录组的结果研究它们在4 ℃和45 ℃处理的叶片、枯萎病菌FocTR4处理的根系以及自然成熟和乙烯催熟的不同成熟阶段的果实中的表达情况。结果显示：MaGLP家族共有44个成员,编码区CDS序列长度为567 ~ 2 103 bp,分布于除10号染色体外的所有染色体上。大部分GLP基因包含1 ~ 2个外显子,多数GLP具有信号肽且主要定位在胞外。进化树分析发现,MaGLP可分为8个亚家族,其中亚家族M为香蕉特有。顺式作用元件和TFBS预测结果显示,MaGLP启动子区存在多种植物激素和逆境胁迫相关响应元件以及7种TFBS。MaGLP成员在香蕉不同组织部位中的表达水平差异较大且受多种胁迫调控。其中MaGLP5-1和MaGLP9-8对各种处理均有响应,MaGLP1-2和MaGLP9-4受高温、低温胁迫抑制,而MaGLP9-6受高温、低温胁迫诱导,MaGLP5-4受高温和FocTR4调控,MaGLP4-4仅响应高温胁迫。研究结果表明MaGLP在香蕉抵御逆境过程中发挥重要作用。     

Changes in antioxidants and fruit quality in hot water-treated ‘Hom Thong’ banana fruit during storage

The effects of hot water treatment on antioxidants and fruit quality were investigated in banana fruit of cv. Gros Michel (Musa acuminata, AAA Group, locally called cv. Hom Thong) by immersing fruits in hot water (50 °C) for 10 min, before storage at 25 °C for 10 days or 14 °C for the first 8 days followed by storage at 25 °C for the second 8 days until ripening. Quality parameters including peel color and pulp firmness indicated that hot water treatment helped to delay banana fruit ripening at both storage conditions. Hot water treatment decreased the levels of hydrogen peroxide (H₂O₂) and malonydialdehyde (MDA) during storage at 25 °C. Glutathione (GSH and GSSG) contents and the ratio of GSH/GSSG during fruit approaching ripening were significantly induced in hot water-treated fruits while ascorbic acid (AA) contents were slightly increased. In addition, the combined treatment increased free phenolics and flavonoids during storage. Results suggest that hot water treatment has led to an induction of antioxidants in banana fruits as indicated by an increase of antioxidants and a decrease of H₂O₂ during ripening, and all of which result in a delayed ripening of banana fruit.     

Hydrolytic and oxidative enzymes during banana ripening

The relative activities of 5 hydrolytic and oxidative enzymes, viz. alpha-amylase, starch phosphorylase, acid phosphatase, peroxidase and catalase, increased considerably in 3 cultivars of banana fruits stored for 5 weeks at 20°C. An upsurge in the activities of all the enzymes, having as a maximum about 1.2–19.1 times their initial level, was observed during the ripening at 20°C. The 3 banana cultivars differed greatly in the activities of all the 5 enzymes studied.     

The post-harvest ripening of water stressed banana fruits

SUMMARY

Maintaining banana fruit in a low humidity environment accelerated fruit ripening. This was reflected in an earlier increase in respiration and ethylene production and more advanced peel colour and pulp sugars. At the end of the trial the fruit kept in low humidity were yellow with green tips (stage 5) whereas those kept at high humidity were still green (stage 1-2). Fruit kept at low humidity did not show a large increase in pulp ethylene production compared with the fruits stored at high humidity. This difference occurred despite a large increase in the 1-aminocyclopropane-l-carboxylic acid (ACC) content of both samples, with the low humidity fruit preceding the high by two days. The peel ethylene production of the low humidity stored fruit increased dramatically as the fruit ripened, coinciding with an increase in ACC. The ACC oxidase activity of the peel reflected the ethylene production with a large increase in the low humidity stored fruit and a later, smaller increase in the high humidity stored fruit. The ACC oxidase activity of the pulp of both low and high humidity stored fruit increased gradually during storage. The changes in ethylene production are discussed with reference to banana ripening being regarded as co-ordinated by pulp ethylene production while the peel is passive, depending on pulp ethylene production for degreening.     

水杨酸甲酯对香蕉苗抗寒生理特性的影响

试验用0、0.5、1.0、1.5 mmol/L等4个浓度的水杨酸甲酯喷施香蕉苗,研究水杨酸甲酯对香蕉苗抗寒性能的影响.结果表明,水杨酸甲酯可以提高低温胁迫下香蕉苗叶片SOD总活性、POD活性、可溶性糖含量和叶绿素含量,降低相对电导率和超氧阴离子 (O2-·)产生速率.在各个浓度处理中,以0.5 mmol/L的水杨酸甲酯对提高香蕉苗抗寒性效果最好.     

MaCDPK7, a calcium-dependent protein kinase gene from banana is involved in fruit ripening and temperature stress responses

Calcium-dependent protein kinase (CDPK) is an important Ca²⁺ sensor in plant development and responses to stress stimuli. Banana fruit is a typical climacteric- and chilling-sensitive fruit. The roles of CDPK genes in the ripening and chilling response of banana fruit are unclear. We isolated a cDNA fragment with full-length coding MaCDPK7 (HM061075) from fruit peel tissue. Induction of MaCDPK7 expression in fruit peel was observed 0.5 h after phytohormone ethylene treatment, earlier than the up-regulation of MaACO1 and MaACS1, coding a 1-aminocyclopropane-1-carboxylate oxidase and 1-aminocyclopropane-1-carboxylate synthase, respectively. Penetration of calcium signaling blockers, EGTA, or LaCl₃ inhibited the ripening and gene expression of MaCDPK7, MaACO1, and MaACS1 in the in vitro cultured peel pieces, but Ca²⁺ application removed the inhibitory effect of EGTA and LaCl₃. This suggested that MaCDPK7 might be a positive regulator involved in the calcium signaling in banana fruit ripening. Under temperature stresses, we found that MaCDPK7 gene expression increased 3 h after hot water dipping (HWD). The HWD-treated fruits exhibited markedly less chilling injury (CI) than control fruits in cold storage. Stored at 7°C (CI temperature) dramatically increased MaCDPK7 gene expression, while pre-treatment of HWD repressed the induction in cold storage. These results show that the MaCDPK7 gene is involved in regulating banana fruit ripening and chilling resistance induced by heat treatment.