The influence of sucrose,ethanol and calcium nitrate on the freezing-point and long-term low-temperature storage of carnation flowers

Both tight bud and open carnation (Dianthus caryophyllus L.) flowers survived ?4°C for 5 days without injury if flowers were pulsed with 20% sucrose at 25°C for 24 hours prior to storage. Between the 8th and 10th day of storage, both stem and floral tissue froze. Flowers pulsed with 10 or 20% ethanol for 24 hours at 25°C survived ?2°C for 5 days, while those pulsed in water failed to open normally or were frozen when stored at 0°C for 5 days. Flowers stressed (wilted) for 24 hours at 25°C survived for only 5 days at ?4°C. After pulsing, tight buds were more resistant to freezing than open flowers and stem tissue was more resistant than petal tissue. However, during storage stem tissue froze before petal tissue. Using exotherm analysis, petal tissue froze at ?2.3 or ?4.7°C when first pulsed with water or sucrose and at ?3.0 and ?3.8°C after 7 days.     

Use of low-pressure storage to improve the quality of tomatoes

Freshly harvested vine-ripened tomatoes (Solanum lycopersicum cv. Neang Pich) were stored at low pressure (4 kPa) at 10°C for 11 days with 100% RH. Fruit quality was examined upon removal and after being transferred to normal atmosphere (101 kPa) at 20°C for 3 days. Weight loss was significantly lower in fruits which were stored at low pressure (4 kPa) than in fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruits that were stored at low pressure (4 kPa) reduced calyx browning by 12.5%, and calyx rots by 16%, compared to fruits that were stored at regular atmosphere (101 kPa) at 10°C. Fruit firmness was not significantly different between fruits stored at low pressures (4 kPa) and the normal atmosphere (101 kPa), with an average firmness of 14 N after fruits were stored at 10°C for 11 days. There was no difference in the SSC/TA ratio. The results suggest that a low pressure of 4 kPa at 10°C has potential as an alternative, non-chemical postharvest treatment to improve tomato quality during storage.     

Effect of low-pressure storage on the quality of green capsicums (Capsicum annum L.)

Green capsicums (Capsicum annum L.) were stored under low pressure (4 kPa) at 10°C for 5 and 11 days with 100% RH. The results showed that the incidence of stem decay under low-pressure storage for 5 and 11 days and storage at ambient atmosphere at 20°C for 3 days was lower compared to fruits that were stored at regular atmosphere at 10°C. Fruit that had been stored at low pressure at 10°C had no symptoms of flesh rots for up to 11 days, whilst fruit which had been stored at regular atmosphere at 10°C had 6% flesh rots after 11 days storage at 10°C.There was no difference in flesh firmness and colour retention between fruits stored at low pressure and regular pressure at 10°C. Capsicums stored at low pressure had higher overall acceptability compared to fruit that were stored at regular atmosphere at 10°C. These results demonstrate the potential of low pressure storage as an effective technique to manage capsicum fruit quality, however, there was no additional benefit when fruits were stored at low pressure for more than 5 days.     

Interaction of Maximum Daily Trunk Shrinkage and Fruit Quality in European Plum

Maximum daily trunk shrinkage (MDS) has been suggested as an appropriate indicator of plant water status because it is closely related to stem water potential. Interaction of MDS and fruit quality was studied in plum (Prunus domestica L. ‘Jojo’/Wavit and ‘Tophit plus’/Wavit) in temperate climate. According to the MDS data, trees were grouped as low MDS (LMDS) and high MDS (HMDS). Fruit quality was analysed during fruit development (95, 103, 117 DAFB for ‘Jojo’ and 99, 112, 121 DAFB for ‘Tophit plus’) before commercial harvest. Fruit picked at commercial harvest (137 DAFB and 140 DAFB for ‘Jojo’ and ‘Tophit plus’, respectively) were stored at 2 ± 0.5?°C (90 ± 2% RH) for 28 days, and 2 days shelf life at 20?°C providing 6 measuring dates postharvest. Results confirmed that MDS was positively correlated with water vapour pressure deficit also in the apparent temperate, semi-humid climate. Transpiration of fruit from high crop load and resulting HMDS trees, which can be assessed as physiologically drought, was low compared to that of fruit from LMDS trees. Furthermore, HMDS tree grown plums had enhanced soluble solids and dry matter contents with a tendency of reduced fruit size.     

Quality of raisins under different packaging and storage conditions

We determined the effect of different storage systems and packaging on the quality of ‘Sultana Seedless’ raisins. The fruit were packed in plastic boxes and kept under controlled atmosphere (1% O₂ and 3% CO₂) at 0°C and 75–85% RH for 12 months (CA), packed in vacuum bags and kept under normal atmosphere (21% O₂–0.03% CO₂) (NA) and packed in thin plastic bags + carton boxes and kept under ambient condition (semi-refrigeration), at 0°C and 90% ± 5 RH for 12 months (AC). Fruit kept under CA or NA had acceptable fruit quality in terms of general appearance and taste for 10 months, whereas fruit quality was unacceptable at that time under AC. Fruit under NA had less weight loss than fruit under the other conditions. Differences in skin colour were relatively small, apart from the h° values. Concentrations of ochratoxin A were generally higher with AC. External appearance and taste were better with CA and NA. As a result, raisins can be stored for 10 months with good quality in vacuum package in NA (0°C and 90% ± 5 RH) and CA (1% O₂–3% CO₂) at 0°C and 75–85% RH.     

Changes in parameters of cell senescence in carnation flowers after cold storage

The effects of cold storage on vase life, ethylene (C₂H₄) production, and parameters of cell senescence, were measured in flowers of spray carnation (Dianthus caryophyllus L.), cultivar ‘Pink Royalette’. Storage for 6 or 12 days at 2°C led to a reduction in the subsequent vase life at 20°C. In addition, storage caused a reduction in the time between the rise in ethylene production and the end of vase life. That is, cold storage increased the sensitivity of the petal cells to endogenous C₂H₄.Normal aging of flowers for 6 days at 20°C led to decreased capacity of petals to take up [¹⁴C] sucrose, decreased activity of membrane ATPase, increased membrane microviscosity and decreased membrane phospholipid content, relative to the levels in fresh flowers. However, cold storage of flowers for 6 days at 2°C caused opposite changes in the levels of these senescence parameters (measured at constant temperature). It was concluded that cold storage does not simply lead to a slow rate of senescence, but has other effects on cell properties.     

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.     

Early forcing of narcissus: The effects of lifting date and stage of floral development at the start of cooling

Early Narcissus flowers may be obtained if bulbs are lifted early from the field, warm-stored (35°C) and then cool-stored (9°C) before forcing in a glasshouse. The earliest satisfactory forcing was investigated, in ‘Carlton’ and ‘Fortune’, by lifting weekly from 27 May to 22 June, and storing at 17°C for 0–7 weeks between warm- and cool-storage. Storage at 17°C is usually intercalated to allow the completion of flower differentiation prior to the start of cool storage.After warm-storage, the bulbs lifted on 27 May and 22 June had reached Stages Sp and A2 of flower differentiation, respectively; 5–7 weeks of 17°C-storage were then needed to reach complete flower differentiation (Stage Pc). Cool storage was therefore begun with bulbs ranging from Stage Sp to Stage Pc. The earliest cooled bulbs had progressed only to Stage A2, and all others to Stage Pc, after 14–16 weeks of cool storage. No floral defects (e.g., split paracorolla) were noted in any treatment, but in ‘Carlton’, about half the bulbs lifted on 27 May and stored for 0 or 1 week at 17°C did not yield a flower, due to failure of the scape to elongate and death of the flower bud within the spathe.Duration of the glasshouse period was reduced by later lifting and by longer 17°C-storage, but following lifting on 15 or 22 June and 2 or more weeks at 17°C, differences were trivial. For flowering within 30 days in the glasshouse, 5 or 6 weeks' 17°C-storage was needed with 27 May lifting, reducing to 1 week at 17°C after 22 June lifting. Flowering within 21 glasshouse days was achieved only after 15 or 22 June lifts followed by 4–5 weeks at 17°C. The earliest flowers in ‘Fortune’ (7 November) were produced following 3–5 weeks at 17°C after lifting on 27 May or 1 June, or following 1–2 weeks at 17°C after later lifting. In ‘Carlton’, the earliest flowers (23 November) followed 2–3 weeks at 17°C after lifting between 1 and 15 June, or 0–1 weeks at 17°C after the last lifting date (22 June). Following the use of 3 weeks' 17°C-storage, flowering date was about equal, irrespective of lifting date. However, further extension of 17°C-storage resulted in a delay in flowering date. Scape length increased irregularly with longer storage at 17°C; scapes were taller following later lifting (8–22 June) than following earlier lifting. Differences in flower diameter between treatments were relatively small.     

Long-term storage of carnations cut at the green-bud stage

Carnation (Dianthus caryophyllus L.) cultivar ‘Scania 3C’ flowers were cut, either as tight buds or when coloured petals had begun to be visible as a “red cross”, and treated with various chemical solutions prior to storage for 14, 16, 20 or 24 weeks at 0–1°C.Pre-conditioning in a solution containing silver thiosulphate (STS) 550 mg/l and sucrose (S) 100 g/l improved the quality of flowers opened after 14 weeks of storage; flower diameters and vase-life were similar to those of fresh, non-stored flowers. Carnation buds were also successfully stored for up to 16 weeks when pre-conditioned with STS and sucrose, but the vase-life of opened flowers was shorter than that of freshly cut buds. The use of this preservative in conditioning, combined with dip treatment in a 0.1% solution of the potent fungicides Rovral or Sumilex before storage, improved the quality of flowers after 16–24 weeks of storage and allowed a vase-life of 7–8 days, respectively. Storage of carnation buds for 20 weeks at low pressure conditions (LPS) considerably improved the quality of flowers compared with 20 weeks of a standard air-storage technique. Carnation buds stored under LPS conditions all developed into fully opened flowers, irrespective of pre-conditioning, although acceptable quality and vase-life were only achieved by those which were pre-conditioned with STS+S prior to storage.     

Post-Harvest Studies on Autumn-Drilled Bulb Onions. The Effect of Harvest Date,Conditioning Treatments and Field Drying on Skin Quality and on Storage Performance

Overwintered onion cvs Express Yellow and Senshyu Semi-globe Yellow were harvested at 80% foliar fall-over (early June) and two and four weeks later, in 1975 and 1976. Plants were conditioned for one (1975) or two weeks (1976) at 20°C, 70% RH or 30°C,60% RH or field dried, and then stored at ambient temperature. Measurements of fresh weight loss during the first six weeks after harvest in 1976 indicated that drying was slow and was incomplete after 14 days conditioning at 30°C. Skin staining and splitting generally increased with delay in harvest date. Skin colour improved with delay in harvest date and with conditioning at 20°C. Wastage due to both rotting and sprouting during storage was generally lower when plants from the first two harvest dates were conditioned at 30°C. These bulbs are likely to be useful for long-term storage as total wastage levels of only 20% were reached in both cultivars after 3-5 months storage. Good field drying of the bulbs could not be consistently obtained and consequently storage performance was more variable than for bulbs conditioned at 20 °C and 30 °C before storage.     

The effect of preservatives on water balance in cut clematis flowers

A positive water balance is crucial for longevity of cut shoots. When water loss by transpiration exceeds water uptake by cut flowers, wilting symptoms appear. Clematis is a very attractive plant which can be used as a cut flower provided that suitable cultivars are chosen. The vase life of four cultivars tested ranged between 6.7 days and 9.0 days and the standard preservative – 200 mg·dm^?3 8-hydroxyquinoline citrate (8HQC) plus 2% sucrose – prolonged it significantly in two cultivars, while 8HQC alone was efficient in only one. The preservatives delayed reduction in fresh weight. An enhancement of water uptake by the preservatives resulted in prolonged vase life of flowers in two cultivars. However, the effect of preservatives on transpiration was not related to longevity. In addition, longevity did not depend on the xylem vessel size: the cultivar with the longest vase life had the lowest average xylem vessel diameter while the cultivar with the largest vessels had an intermediate vase life. Preservatives did not always affect the number of blockages in xylem appearing during vase life. Generally, the effects of preservatives on the elements of water balance in cut shoots of clematis were not directly related to the postharvest longevity.     

Optimization of agrotechniques in the cultivation of Luffa acutangula

Germination requirements, flowering pattern, planting density and growing regimes were examined for Luffa acutangula (L.) Roxb. Maximum germination (50%) was obtained at 35°C, and at 8, 12, and 45°C germination was completely inhibited. Partial removal of the seed coat increased the percentage of germination while vernalization and exposure to salinity 5=50 mM NaCl reduced it. Planting season influenced flowering pattern, with significantly more female flowers being produced in spring-summer (long days and high temperatures) than in autumn-winter (short days and low temperatures). A high yield of 44.5-47.3 Mg ha 1 was obtained for plants trained on trellises at planting densities of 10,000 and 20,000 plants ha-1. Fruits kept at low temperatures showed the least deterioration during storage, a shelf life of about two weeks being demonstrated at 4°C.     

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.     

Author index

Open carnation (Dianthus caryophyllus L.) flowers survived storage at ?3°C for 20 days if previously pulsed with 6% dimethylsulfoxide (DMSO) and 20% sucrose. However, vase life after removal was only 1 day. With 15 days storage, such flowers were acceptable for 7.5 days. With DMSO alone, the possible freezing time was shorter than with sucrose alone. A 5% solution of DMSO increased longevity compared to the water control when flowers were not stored.     

Comparison of Climate Change Effects on Pome And Stone Fruit Phenology Between Balkan Countries and Bonn/Germany

The objective of the joint project between the two universities of Bonn and Sarajevo was to study the effects of climate change associated with warmer winter and spring temperatures on fruit tree phenology. Changes in flowering date of apple and cherry were correlated with local weather data obtained concomitantly on-site at four locations in the Balkan countries Slovenia, Serbia, B & H and at Bonn, Germany.Phenological data of flower opening (F1; BBCH 61) of apple cv. ‘Golden Delicious’ originated from 55 years at Cacak (44?°N, Serbia) and at Klein-Altendorf, University of Bonn (50?°N), cv. ‘Bobovec’ from the University of Ljubljana (46?°N, Slovenia) and cherry cv. ‘Burlat’ (35 years at Klein-Altendorf, 50?°N) and 20–30 years at Tuzla (44?°N, B & H) and Mostar (43?°N, Bosnia & Herzegovina; B & H).The annual precipitation showed a negligible change in the last 55 years of ±5% in the Balkan countries (e.?g. Cacak, 699?mm), but only ±1.8% at Klein-Altendorf (605?mm) with a slight shift to more winter rainfall.Regression analysis showed an increase in mean temperature of 1.7?°C (annual) and 1.45?°C for the vegetation period at Klein-Altendorf (last 55 years), Germany. In the evaluated Balkan stations, the greatest increase in annual air temperature between two climate phases (until 1987 versus from 1988 until now) was at Ljubljana (1.4?°C) and Cacak (1.2?°C) in contrast to the least increase (0.3?°C) at Tuzla (annual average 10?°C) and an intermediate value (0.9?°C) in the warmer Mostar (annual average 14.5?°C).This recent temperature increase advanced flower opening by 10–14 days for apple such as cv. ‘Golden Delicious’ at Cacak and 7–10 days (last 55 years) at Bonn and 4–5 days (last 35 years) for the early cherry cv. ‘Burlat’ at Klein-Altendorf/Bonn; at Mostar and Tuzla, the effect of climate change was greater with the early cherry cv. ‘Burlat’ (26 days) compared with the difference of the late cherry cultivar (16 days). Before recent climate change (1973–1987), cherry flower was advanced by 10 days in the warmer med climate at Mostar but delayed by 16 days in the cooler Tuzla. The results, i.?e. the flower advancement in the Continental climate but flower delay in the med climate, are discussed with respect to the risk of late frost and countermeasures to combat climate change effects.     

Storage of some local and introduced mango cultivars grown in Trinidad

The fruit characteristics and storage potential of some local and introduced mango cultivars grown in Trinidad were compared. At ambient temperature (28–32°C), fruit could be stored satisfactorily for between 3 and 8 days, after which ripening rapidly occurred. At 14°C, storage life was increased to as much as 18 days (cultivar ‘Graham’). Enclosure of fruits individually in polythene bags increased storage life at either ambient or 14°C temperature, while treatment with 3% Sta-fresh wax increased storage at ambient but not at 14°C. In the case of ‘Doodooth’, which was highly susceptible to anthracnose, treatment of fruit with hot water (52 ± 2°C) containing 500 or 1000 mg l^?4 benomyl for 5 min reduced the incidence of disease. Results are discussed in relation to the export potential of mangoes.     

Guazatine control of sour rot in lemons,oranges and tangors under various storage conditions

Guazatine (1-17-diguanidino-9-aza-heptadecane acetate) was compared with sodium orthophenylphenate (SOPP), sec-butylamine (2-AB), benomyl and tridemorph for the control of citrus sour rot (Geotrichum candidum) under local marketing, export, and ethylene (C₂H₄) degreening storage conditions. Guazatine at 25–125 mg/l gave better control than 20 g/l SOPP, 10 g/l 2-AB and 250 mg/l benomyl in artificially inoculated ‘Eureka’ lemons stored at 27° C and high humidity for 6 days. At 500 mg/l, guazatine gave better control than 20 g/l SOPP, 10 g/l 2-AB or 500 mg/l benomyl in dip-inoculated ‘Eureka’ lemons, treated and packaged as for export and stored at 7° C for 2 or 10 weeks. At 250 mg/l, guazatine provided better control than 20 g/l SOPP, 5 g/l 2-AB, 250 mg/l benomyl or 1000 mg/l tridemorph in artificially inoculated ‘Washington’ navel oranges held for 4 days under degreening-conditions of 27° C and 90% RH with added C₂H₄.     

Amount of Cortical and Epidermal Tissue Shed From Roots of Apple

Rates of CO₂ production by cv Idared apples were progressively reduced by lowering O₂ levels from 21% to 2% and 1%. Although lowering the temperature from 4° to 2°C also reduced the respiration rate, fruits stored in 1% and 2% O₂ were respiring faster after 100 days at 0°C than at 2° or 4°C. After 192 days the air-stored fruit also showed an increase in respiration rate at 0°C. These higher respiration rates preceded the development of low temperature breakdown in fruit stored in air, 2% and 1% O₂ at 0°C and in 1% 0₂ at 2°C. Progressively lower O₂ concentrations reduced ethylene production whilst increasing the retention of acid (expressed as malic), soluble solids, chlorophyll and firmness. In the absence of low temperature breakdown the effects of reduced temperature on fruit ripening were similar to those of lowered O₂ concentrations. The quality of apples stored at 4°C in 1% O₂ was markedly better than in 2%; the fruits were also free of core flush (brown core) and other physiological disorders.     

Subatmospheric pressure storage of mango fruits

Ripening of mango fruit is markedly delayed when the pressure in the storage chamber is reduced below 100 mm Hg, and fruit storage life is thus prolonged. The prolongation of storage life is inversely related to the pressure; control fruit stored at 760 mm Hg started to ripen after 16 days in storage at 13°C, while fruit stored at 100 and 75 mm Hg after 25 and 35 days, respectively. Fruit stored at 50 mm Hg remained unripe for 35 days. No effect on ripening was recorded at pressures above 250 mm Hg, while at pressures below 50 mm Hg the fruit desiccated. All fruits stored at subatmospheric pressure ripened 3–4 days after transfer to shelf life at 25°C. However, green mango fruits of the colored cultivars like ‘Haden’ and ‘Maya’, stored at subatmospheric pressure for a prolonged period, did not develop the proper red or orange color during shelf-life, but turned pale yellow instead. Treatment with ethylene upon removal from storage slightly improved color development in these fruits.     

Inhibition of flowering of Mexican- and Guatemalan-type avocados under tropical conditions

Avocado trees of a range of cultivars growing in Darwin, northern Australia (average yearly maximum 33°C, minimum 23°C), were observed for flower and shoot development. Terminal buds of the cultivars ‘Fuerte’, ‘Rincon’ and ‘Edranol’ sampled in July were not floral. Buds which did not burst were sampled in September and they contained developing flowers with perianth primordia. Vegetative extension growth resulted from laterals proximal to the inhibited terminal buds.Avocado trees of the cultivars ‘Fuerte’ and ‘Hass’ which had initiated floral buds were transferred to controlled environment chambers with 33°C day, 23°C night ($\text{33}\text{23}$) or 25°C day, 15°C night ($\text{25}\text{15}$) with a 12-h photoperiod and photon flux density of 400 μmol m^?2 s^?1 (400–700 nm). At $\text{33}\text{23}$ the trees had fewer flowers and a shorter flowering period than at $\text{25}\text{15}$. Inhibited floral buds and lateral vegetative extension resulted at $\text{33}\text{23}$, as observed in northern Australia. The unburst buds had developing flowers with perianth and stamen primordia.The controlled environment experiments showed that the abnormal flushing behaviour of Mexican- and Guatemalan-type avocados growing in northern Australia was due to high temperature. Floral development was inhibited at the stage of stamen differentiation.