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Abdullah Al-Solaiman and Fouad M. Basiouny

Mango fruits (Mangifera indica L. cv. Tommy Atkins) were harvested at early physiological maturity to study the effects of postharvest treatments on storage and fruit shelf-life. The fruits were subjected to control atmosphere (20 CO2 +3% O2, and 30% CO2 + 3% O2), liquid coating (NatureSeal and Polyamine), and ethanol vapor. The fruits were kept for 4 weeks at 50 + 3°F then removed from the cold storage and maintained at room temperature. Mango fruits stored at high level of CO2 or dipped in NatureSeal had better shelf-life than fruits stored at a low level of CO2 or with ethanol vapor.

Open access

J. P. Syvertsen and M. L. Smith Jr.

Abstract

An inexpensive, well-stirred chamber for measuring net fluxes of CO2 and H2O vapor from single leaves was constructed from readily available materials. It incorporates a fan that maximizes air turbulence and boundary-layer conductance. Leaf temperature can be maintained within ± 0.5°C of air temperature. Temperatures can be varied for experimental purposes or can be maintained constant even under varying heat loads using a temperature-controlled water circulator. When used in conjunction with such a circulator and CO2 and H2O vapor analyzers, this chamber can become an inexpensive yet useful component of a gas-exchange system.

Open access

Harry G. Ponder, Charles H. Gilliam, and Heather J. Dawes

Abstract

Photinia Χ fraseri Dress (Fraser Photinia) plants were dug and burlapped in the morning and afternoon during midsummer with or without previous irrigation or antitranspirant treatment (di-1-p methene = Vapor Gard). Plants were shipped for one day, held for 2 weeks under lath, and then planted. Moisture stress, indicated by shoot water potential, was monitored throughout the study and survival was rated in September. Use of the antitranspirant and morning digging reduced moisture stress of plants. Morning-dug plants had 80% or greater survival even without irrigation. Afternoon digging gave low survival with or without irrigation but afternoon digging plus Vapor Gard gave 100% survival.

Free access

Christine Schumann, Henrik Jürgen Schlegel, Eckhard Grimm, Moritz Knoche, and Alexander Lang

. To provide a more useful understanding of fruit water relations in cherry, and were quantified in developing fruit using a vapor pressure osmometer, a compression plate, and a cell pressure probe. The value was also determined by following

Free access

Barbara M. Reed, Sara Schwanke, and Rebecca Shala

Cryopreservation in liquid nitrogen (LN) is relatively routine for many small, desiccation-tolerant (orthodox) seeds. Seeds of Pyrus species are considered orthodox but have not been evaluated for LN storage. Seeds of freshly collected P. communis L. (`Bosc') were evaluated for germinability and by TZ staining after exposure to four LN treatments: 1) direct immersion and direct removal; 2) direct immersion and 1 minute in LN vapor phase before removal; 3) 2 minutes in vapor phase before immersion and direct removal; and 4) 2 minutes in vapor phase before immersion and 1 minute in vapor phase before removal. Fresh `Bosc' seed viability evaluated by TZ and greenhouse germination tests remained high (83% to 100%) following four types of LN treatments, compared to the controls (77% to 87%). Differences in `Bosc' seed viability were small and TZ results showed no significant differences among the LN treatments. Direct LN immersion and removal resulted in significantly more greenhouse-germinated `Bosc' seeds than the other treatments and fewer control seeds germinated than any LN treated seeds. Fresh `Bosc' seed cryopreserved at 7.9% moisture exhibited high germinability by both TZ and germination tests. LN exposure caused no physical damage to the seeds. Chemical name used: 2,3,5-triphenyltetrazolium chloride (TZ).

Free access

Juan Carlos Díaz-Pérez, María Dolores Muy-Rangel, and Arturo Gaytán Mascorro

Fruit water loss significantly affects the quality of bell peppers. The objective of this study was to determine the effect of fruit weight, size, and stage of ripeness on the rate of water loss and permeance to water vapor. Fruit surface area/weight ratio decreased logarithmically with increases in fruit size, with smaller fruit showing larger changes in the ratio than larger fruit. Mean water loss rate for individual fruit and permeance to water vapor declined with increases in fruit size and as fruit ripeness progressed. Fruit surface area/weight ratio and rate of water loss were both highest in immature fruit and showed no differences between mature green and red fruit. In mature fruit, permeance to water vapor for the skin and calyx were 29 μmol·m–2·s–1·kPa–1 and 398 μmol·m–2·s–1·kPa–1, respectively. About 26% of the water loss in mature fruit occurred through the calyx. There was a decline in firmness, water loss rate, and permeance to water vapor of the fruit with increasing fruit water loss during storage.

Open access

L. G. Albrigo

Abstract

Antitranspirant sprays of 5 film-forming materials were compared on mature Citrus sinensis (L.) Osbeck cv. Valencia trees for film persistence and reduction of fruit weight loss after harvest. These materials were also sprayed on young ‘Pineapple’ (C. sinensis) or ‘Valencia’ orange trees growing in 7.6 liter containers on which weight loss was subsequently measured for 48-hour periods after watering. Spray solutions of equal or known film-forming ingredients (solids content) of 1 to 4% (weight/weight) were applied and compared. Plantgard film did not significantly increase the leaf epicuticular coating nor did it reduce fruit weight loss or young tree water use. Mobileaf, Vapor Gard, Nu-Film-17, and Wilt Pruf NCF did result in heavier leaf coatings and less fruit weight loss than the controls. Mobileaf and Vapor Gard reduced potted tree water use. Some loss of effectiveness and coating thickness occurred 5 months after application, but only a small nonsignificant change in effectiveness occurred during the first 2 months after application. Mobileaf and Vapor Gard appeared to give the best antitranspirant protection for the initial 2 months and Vapor Gard for 5 months.

Open access

D. M. Glenn, J. W. Worthington, W. V. Welker, and M. J. McFarland

Abstract

Infrared (IR) thermometry has not been extensively applied in deciduous tree fruit production to determine water use. The objectives of this study were to a) examine IR measurement techniques for evaluating canopy temperatures in peach [Prunus persica (L.) Batsch.] trees; b) evaluate a foliage-minus-air temperature- (Tc – Ta) based diffusion equation for vapor flux used to predict tree water use; and c) measure the Tc – Ta response of irrigated peach trees over a range of air vapor pressure deficits. The mean Tc – Ta for a tree was similar for readings made from the canopy sides (horizontal orientation of the IR thermometer) or canopy tops (vertical orientation). Peach tree water use from weighing lysimeters was predicted within 9.4% ± 3% using the diffusion equation for vapor flux. Tc – Ta for irrigated peach trees was related to the air vapor pressure deficit (VPD). Data are presented to show that stomatal response to VPD does alter the Tc – Ta nonstressed baseline for peach at VPD > 2 kPa.

Open access

Linda Thorne and George P. Hanson

Abstract

The relative ozone sensitivities of a 7-parent diallel set of petunia hybrids were compared with their rates of ozone absorption, rates of transpiration, ascorbic acid concentrations, and shoot and root weights. Ozone sensitivity was highly correlated with both ozone and water vapor diffusion resistance, but not with ascorbic acid concentration or shoot-root ratio.

Open access

W. Grierson and W. F. Wardowski

Abstract

Humidity as related to horticulture is discussed in terms of: ways of expressing humidity levels; physical properties of water vapor; and temperature-humidity and air circulation-humidity interactions. The role of humidity in transpiration, killing freezes, and storage and transport of fruits and vegetables is discussed. Also given are sources of information on methods of recording and controlling humidity in postharvest applications.