Effect of postharvest application of calcium on ripening rates of pears and bananas

Dipping unripe pears (cv Williams Bon Chretien) in a solution of calcium chloride under reduced pressure (125-375 mm Hg) and subsequent storage at 20°C delayed ripening by up to 40% of the time taken for control fruit to ripen. The Ca-treated fruit ripened normally and a taste panel found that it was of good eating quality. However, dipping unripe bananas (cv Cavendish) in CaCl₂ solution, whether under ambient or reduced pressure, accelerated ripening.     

Physicochemical changes in Mazafati date fruits incubated in hot acetic acid for accelerated ripening to prevent diseases and decay

A method was developed and optimized for the accelerated ripening of date fruits of cultivar ‘Mazafati’ to prevent diseases and decay. The date fruits were incubated in hot acetic acid solution 0.5% at 40 + 1 °C for 72 h. During the process some physicochemical changes in the fruits were studied and were found to be comparable with the changes in the fruits that naturally ripened on the tree. Fruit firmness, water insoluble solid (WIS), protein, pH, L*a*b* and E decreased during accelerated ripening whereas in control samples at 4 °C increased. Total solid (TS), total soluble solid (TSS) and acidity were slightly higher in treated fruits compared to control fruits. The greatest loss of fruit firmness occurred during the first 12 h of incubation. Organoleptic tests also showed little difference between the naturally ripened fruits on trees and accelerated ripened fruits in hot acetic acid. Overall there was no difference between the fruits and were readily acceptable to consumers.     

气调贮藏下草酸处理对杧果果实成熟和腐烂的影响

杧果(MangiferaindicaL.)采后分别经0(对照)和5mmol/L草酸溶液浸泡10min后,在气调犤6%CO2+2%O2,(14±1)℃犦条件下贮藏。结果表明:草酸处理使果实软化和果肉可溶性固形物增加的速率减缓、果实的病情指数和腐烂率降低;同时,果皮的超氧阴离子()产量和过氧化氢(H2O2)含量降低、SOD活性提高和还原型抗坏血酸(ASA)采后损失量减少。分析认为草酸处理提高果实抗氧化能力和降低活性氧((AOS)代谢与延缓果实的成熟和抑制病情、腐烂发生相关,草酸处理是果采后贮藏保鲜的一种可选新方法。     

采后褪黑素处理对杏果实成熟的影响

为研究采后外源褪黑素处理对杏果实低温贮藏期间品质及生理的影响,以确定最佳的褪黑素处理浓度,并明确其对杏果实成熟的调控机理,试验以‘兰州大接杏’为材料,采用50～1 000μmol/L褪黑素溶液浸泡杏果实15 min,分析低温[(2±2)℃,相对湿度73%±2%]贮藏期间杏果实乙烯释放量、呼吸强度、硬度、色泽等品质及生理指标的变化。结果表明:不同浓度的外源褪黑素溶液处理均显著提高了杏果实的呼吸强度以及乙烯释放量,贮藏第12 d时,50μmol/L外源褪黑素处理杏果的呼吸强度较对照提高32.8%,同时,贮藏第8 d时,该处理的乙烯释放量为对照的2.2倍;其次,50μmol/L褪黑素溶液处理有效促进了杏果实的软化。此外,褪黑素处理杏果实后有利于提高果实可溶性固形物、可滴定酸含量,有效保持果实抗坏血酸含量。综合来看,50μmol/L外源褪黑素处理可通过提高采后杏果实乙烯释放量和呼吸强度,促进果实成熟,进而加速杏果实最佳食用品质的形成。     

果蔬乙烯催熟系统设计及香蕉催熟试验

【目的】综合精准自动控制果蔬采后催熟所需温度、湿度、乙烯及CO_2气体参数,实现用乙烯气体安全自动催熟采后果蔬。【方法】在可控温控湿贮藏库中,设计加装乙烯气体输入感应装置、CO_2感应清除装置和微电脑调控程序终端,组成采后果蔬乙烯气体催熟系统,将库内多传感器和执行机构与微电脑调控终端连接,通过程序实现自动控制催熟各参数,并试验应用于香蕉的催熟。【结果】乙烯气体催熟系统可精确有效地自动控制贮藏库内的湿度、乙烯和CO_2气体体积分数,通入乙烯气体催熟处理2~3 d即可使香蕉达到外观销售需求,且贮放过程中香蕉的果肉硬度降低慢,货架期达8 d。【结论】同乙烯利催熟相比,采用该系统催熟香蕉具有安全自动、蕉果黄色色泽(b*值)和亮度值(L*)较高、后熟软化速度慢、货架期延长2~3 d等优点,可替代传统的乙烯利催熟方法。     

部分香蕉品种SSR指纹图谱的构建

采用SSR标记技术构建香蕉品种的分子指纹图谱,为香蕉品种鉴定提供依据。以56份香蕉种质为材料,从199对引物中筛选出5对多态性及稳定性较高的SSR引物进行PCR扩增。5对引物在56个品种中扩增出的多态性带数在11～16个,平均为13.8条;引物的多态信息含量(PIC)在0.8490～0.9022,平均0.8727。依据香蕉SSR带型特征,对每个引物生成的不同带型直接编号,简化香蕉SSR带型记录方法,并利用每个品种的带型编号,建立其DNA分子指纹图谱,5对引物可将56份供试香蕉材料完全区分开。表明SSR标记技术可用以鉴定香蕉种质。     

Effect of stage of ripening and ethephon treatment on color content of paprika pepper

In order to determine the proper time to harvest paprika pepper (Capsicum annuum L.) fruits to obtain maximum extractable color, two maturity indexes were evaluated. Most consistent results were obtained when fully shriveled fruits were harvested.Foliar applications of ethephon (50, 100, 200 and 500 ppm) were made on two cultivars, ‘Paprika-505’ and ‘Paprika-D.Z.’. Total extractable color and capsanthin content were determined using fully shriveled pericarp tissue. Some flower and leaf abscission was caused by treating plants with 500 ppm ethephon and leaves of plants treated with 200 or 500 ppm ethephon turned yellow. Ethephon stimulated ripening and increased the total extractable color and capsanthin levels of paprika fruits. ‘Paprika-505’ contained more total extractable color and capsanthin than ‘Paprika-D.Z.’ as a result of ethephon treatment.     

Rootstock influences the fruit mineral,sugar and organic acid content of a very early ripening peach cultivar

Summary

The influence of rootstocks differing in genetic origin and agronomic performance on the commercial characteristics and chemical composition of the fruit was investigated on the low-chill, very early ripening (fruit development period = 100 d) cv. Maravilha (Prunus persica (L.) Batsch) trained to a Y in a high density planting (2,500 trees per ha). Of the rootstocks tested, five belonged to P. persica (Harrow Blood, Ps B2, Ps C14, Rubira and Rutgers Red Leaf), three were hybrids of P. persica x P. dulcis (GF677, Hansen 2168 and Hansen 536) and two were complex hybrids of P. cerasifera (Mr S 2/5, M x P). The more vigorous graft combinations gave significantly higher yields. Rootstocks significantly influenced mineral content (N, K, Fe and Zn), sugars (sucrose and fructose) and organic acids (succinic) of the fruit, although these differences are not so important as to affect the commercial value of the fruit and to direct the choice towards one rootstock rather than another. Neither fruit weight, skin overcolour, shape nor refractometer value (°Brix) were affected by rootstocks. The short fruit development period together with the heavy pruning required for high density plantings presumably minimized differences in fruit quality between the graft combinations.     

Temperature influences nutrient absorption and uptake rates of bananas grown in controlled environments

We explored the influence of temperature on the concentration of nutrients in banana plants, the nutrient uptake rate, apparent root transfer coefficient ($\text{}\text{?}$ga) and the relationship between accumulation of dry matter and nutrient. Young banana plants (Musa (AAA group, Cavendish sub-group) ‘Williams’) were grown at six temperature regimes (17/10–37/30°C) in sunlit growth chambers for 12 weeks.The amount of nutrient absorbed was influenced by the amount of growth made, but the link between the two differed from one element to another. Temperatures less than $\text{29}\text{22°}\text{C}$ reduced the concentration of all elements in the whole plant, except Fe.Temperature influenced the root uptake rate of B 10-fold; K, Na, Ca, Fe and Zn 3–4-fold; and N, P, Mg, Mn, Cu, Cl 1–2-fold. Among the elements the highest recorded rate was 12 mg g^?1 day^?1 for K at $\text{33}\text{26°}\text{C}$. The optimum temperature for nutrient uptake rates differed among the elements. This was accounted for largely by greater growth at those temperatures of organs with high concentration of particular elements.The $\text{}\text{?}$ga (an estimate of efficiency of uptake) of B varied 12-fold among treatments; K, Ca, Mg, Na, Mn, Zn and Cl varied 3–5- fold and N, P, Cu and Fe varied 2–3-fold.The ratio of relative nutrient accumulation rate, R_m, to the relative growth rate, R_w, was most stable across temperatures for N and least stable for B and Na. However, the trend was for $\text{R}{}_{\mathrm{<mtext>m</mtext>}}\text{R}{}_{\mathrm{<mtext>w</mtext>}}$ to increase as temperature rose, indicating an absorption of nutrients greater than might be expected from a change in growth rate as temperature increased, and a decreased efficiency in their utilization for plant growth.     

The effect of humidity in plantain ripening

An examination of the coordination of ripening changes in plantain fruits (Musa AAB, cultivar ‘Apem’) showed that water stress had no effect on the respiratory rate at the climacteric maximum nor on the time between initiation and maximum. Similarly, water stress had little or no effect on the coordination of changes in CO₂ and C₂H₄ evolution, although it slightly increased the magnitude of C₂H₄ production and of the ACC content of the pulp. Stressed and unstressed fruits showed similar synchronised ripening changes after 2 and 3 days from the commencement of the climacteric. However, after 1 day, peel colouration, pulp softening and total soluble solids were less in stressed than in unstressed fruits. The results are discussed in the light of reported work on dessert bananas (Musa AAA cultivars).     

次氯酸钙处理对金柑采后腐烂及抗氧化物酶活性的影响

【目的】探讨次氯酸钙在金柑果实贮藏保鲜上的应用效果。【方法】以‘金弹’(Fortunella crassifolia Swingle)为材料,分别使用质量浓度为0.15、0.6 g·L~(-1)的次氯酸钙水溶液浸泡金柑果实2 min(温度10~12℃),然后在室温为(10±2)℃、湿度为85%~90%的条件下贮藏30 d,每隔5~7 d取样1次,研究次氯酸钙处理对金柑果实腐烂率、品质以及抗氧化酶活性的影响。【结果】经0.6 g·L~(-1)次氯酸钙处理的果实总酸含量较低,在0.3%左右;贮藏第30天失重率达到4.2%,与对照相比提高1.4%;各处理间可溶性固形物含量在17%上下波动且差异不显著;次氯酸钙处理可有效降低果实腐烂率,减小果实青霉病病斑直径,提高贮藏过程中金柑果实过氧化物酶活性,减缓超氧化物歧化酶活性的降低速率,降低过氧化氢酶活性,减少过氧化氢含量,从而延缓果实衰老。【结论】次氯酸钙可有效延缓金柑果实衰老,在金柑贮藏保鲜中,不同采收期的金柑所需的次氯酸钙浓度不同,对于采收较晚的金柑,0.6 g·L~(-1)次氯酸钙浸泡2 min可有效降低果实腐烂率。     

Sugar changes in Clementine and orange fruit during ripening

Summary

Juice and rind sugar content, fruit volume and rind colour were determined in cvs Fina, Oroval and Hernandina Clementines and in cvs Navelina, Washington Navel and Navelate oranges, cultivars that are harvested at different periods during the season. An accumulation of sugars was observed in all cultivars during ripening, mainly due to an increase of sucrose in the juice and of reducing sugars in the rind. Cv Hernandina, a late Clementine, showed a slower rate of sugar increase in rind.     

Physiological changes in boysenberry fruit during growth and ripening

Summary

Boysenberries (Rubus hybrid) were harvested at five developmental stages (green, “turning”, pink, red and purple) to study changes associated with flavour, colour and firmness, with a particular focus on the different enzymes involved in chlorophyll degradation or cell wall degradation. The level of reducing and non-reducing sugars increased 109- and 52-fold, respectively, between the “turning” and the purple stage. Titratable acidity increased by 84% between the green and the pink stage, but dropped by 41% between the red stage and full ripening. Total phenols displayed their highest values in green and “turning” fruit. Chlorophyll a and b degradation occurred mainly during the early stages of development, and was paralleled by a 2.3-fold increase in chlorophyllase activity and a 5-fold increase in Mg-dechelatase activity between the green and the red stages. Chlorophyll peroxidase activity was high at the green stage, but did not change significantly after the “turning” stage. This is the first report on the activity of chlorophyll-degrading enzymes in Rubus spp. fruits. Anthocyanins increased 11-fold between the “turning” and the pink stages, and an additional eight-fold between the pink and the purple stages. Fruit firmness decreased noticeably during ripening, with a concomitant 10.75-fold increase in polygalacturonase activity, beginning at the “turning” stage. Endo- -1,4-glucanase and -galactosidase activities rose 9.2- and 6.7-fold, respectively, after the pink stage and paralleled the major softening process taking place between the pink and purple stages, when fruit firmness decreased from 3.83 N to 0.29 N. Pectin methylesterase activity was high in pink and red fruit, but decreased by 21% as the fruit turned from red to purple. This is the first report on cell wall enzyme activities whose combined action might be required for the breakdown of natural cell wall substrates during ripening in boysenberry, as happens in other soft fruits.     

Can a post-harvest ripening treatment extend the longevity of Rhododendron L. seeds?

Pre-dehiscent capsules were collected from two Rhododendron griersonianum (Balf.f. & Forrest) trees and either immediately dried in a dry-room (15% relative humidity, 15 °C) or placed in a high humidity room (80% relative humidity, 15 °C) for 30, 60, or 90 d. Further capsules were also collected from the trees at 30 and 60 d, but seeds had been dispersed by 90 d. Seed ageing experiments (60% relative humidity, 45 °C) carried out on these seed-lots and on seeds from a further 10 Rhododendron (L.) species confirmed that short seed lifespans is a trait of the genus, with a mean P₅₀ value of ca. 20 d for this storage environment.     

特早熟温州蜜柑大浦在全州的引种表现初报

全州县咸水林场在调整水果品种结构过程中,于2006年3月上旬从湖南常德和涟源引种特早熟温州蜜柑大浦30000株、宫本20000株（均为枳砧）。种植约27hm^2。管理得较好的几个岗位地2008年开始试结果,667m^2产500～750kg,2009年普遍结果,估计平均667m^2产量1500kg左右。今年8月15日开始采收上市。     

Climatic conditions affect the texture and colour of Cavendish bananas (Grande Naine cultivar)

Relationships between natural production conditions (soil and climate) and physical fruit traits (texture and colour) were studied in Martinique to fuel discussions on creating a label for bananas from the French West Indies. Bananas produced at six sites, under very different conditions, during three different periods of the year, were harvested at the same temperature sum and ripened under identical conditions. The peel of green bananas harvested during the hot humid season was not as hard as that of bananas harvested during the cool dry season. In ripe bananas, an increasing correlation was noted between the rainfall level and fruit firmness (R = 0.88) and peel hardness (R = 0.80). This correlation could explain why bananas produced during the dry season were less firm and, conversely, those produced in highland areas, where rainfall is highest, were firmer. In ripe bananas, a decreasing correlation was also noted between the mean daily temperature and the fruit yellowness (R = 0.84). This interaction could be responsible for the yellower colour of mountain banana pulp and of bananas harvested during the coolest seasons. The green life of bananas harvested during the hot humid season was shorter than that of bananas harvested during the dry and intermediate seasons.     

Identification of organic acid-related genes and their expression profiles in two pear (Pyrus pyrifolia) cultivars with difference in predominant acid type at fruit ripening stage

‘Yandangxueli’ is a pear cultivar with predominant citric acid in the ripe fruit, different from most of pear cultivars such as ‘Gengtouqing’ in which malic acid is the predominant acid type. It was found that ‘Yandangxueli’ accumulated citric acid for three times against that in ‘Gengtouqing’ at fruit ripening stage. To investigate the mechanism of citric acid accumulation in ‘Yandangxueli’, organic acids content, gene expression and enzyme activity were studied in both cultivars. Five genes, Pp:mtCs, Pp:cyAco, Pp:cyIdh, Pp:mtMdh and Pp:cyMe which encoded citric synthase (CS), cytosolic aconitase (cyACO), NADP-dependent isocitrate dehydrogenase (NADP-IDH), NAD-dependent malate dehydrogenase (NAD-MDH) and NADP-dependent malic enzyme (NADP-ME) respectively, were identified from pear fruit. Their expression profiles and the corresponding enzyme activities were determined throughout fruit development in both cultivars. Results from these enzymes indicated that there were no strict relationship between gene expression, enzyme activity and citric acid accumulation. Expression analysis for two Py:vVAtp genes encoding vacuolar H⁺-ATPase A subunit and one Py:vVpp gene encoding Vacuolar H⁺-pyrophosphatase showed that they were all with up-regulated expression at the later development stage of ‘Yandangxueli’ but with down-regulated expression in ‘Gengtouqing’. Therefore, it is concluded that the different ability in citric acid transportation and storage might be involved in the high citric acid content in ‘Yandangxueli’.     

桂林早熟梨果实轮纹病发生规律及其防治

早熟梨是广西继柑桔、荔枝、龙眼、香焦之后的又一大产业。由于南方早熟梨比北方梨要早上市30～45d,在市场上具有更大的竞争优势,极大地促进了广西早熟梨的迅猛发展。     

甜樱桃果实成熟过程中糖累积与品质形成研究

【目的】探明甜樱桃成熟过程中糖积累和品质形成的规律。【方法】以‘雷尼’和‘先锋’甜樱桃为试材,研究了果实成熟过程中可溶性糖以及硬度、果柄拉力、可滴定酸、总酚、抗坏血酸等品质的变化规律。【结果】甜樱桃果实中可溶性糖以葡萄糖、果糖和山梨醇为主。随着甜樱桃果实的成熟,其葡萄糖、果糖、山梨醇、可溶性固形物含量和糖固比例不断升高。‘雷尼’和‘先锋’樱桃的3种可溶性糖分别在成熟期3和成熟期5迅速积累,然后缓慢增加。果实的硬度和果柄拉力均随果实的成熟不断降低,总酚含量均在成熟期3时急速降低,之后趋于平稳。2个樱桃品种的可滴定酸、抗坏血酸含量和固酸比总体呈升高趋势,其中,‘雷尼’可滴定酸含量和固酸比在成熟期2之后趋于平稳。完熟期时‘雷尼’樱桃的可滴定酸含量和‘先锋’樱桃的抗坏血酸含量有所降低。2个樱桃品种的硬度、果柄拉力、可溶性固形物、葡萄糖、果糖、山梨醇6个指标之间均呈显著相关性。【结论】甜樱桃果实在成熟过程中糖含量呈上升趋势,成熟期3和成熟期5分别是‘雷尼’和‘先锋’樱桃糖积累的关键期,果实硬度、果柄拉力和总酚含量呈下降趋势,其他品质指标变化不一致。     

果树EST在果实发育和成熟研究中的应用

表达序列标签(EST)已成为植物功能基因组学研究的重要手段,在揭示植物生长发育机制方面起着重要作用。近年来果树EST研究与应用也得到快速发展,dbEST数据库中EST信息量超过5 000条的果树已达37种。着重介绍柑橘、葡萄、苹果、猕猴桃、桃、草莓和杨梅等果树EST在果实发育和成熟研究中的应用进展,并展望今后研究的热点和趋势。