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  • Author or Editor: F. Liu x
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Ripening-initiated ‘Valery’ bananas (Musa sp.) held in gas mixtures containing 10 ppm ethylene, 2 to 10% O2 and 0 to 10% CO2, ripened at a slightly lower rate than in air and had comparable quality when ripe. Fruit ripened very slowly and had lower quality, however, when the O2 concentration was reduced to 1%. Ethylene gas, which was released from ethephon ((2-chloroethyl)phosphonic acid) solution applied to a small piece of sponge, initiated ripening of bananas in polymeric film packages. Three kinds of film regulated atmospheric composition inside packages suitable for banana ripening and holding. Making 1 or 3 pin holes through the film package increased the O2 concentration but had little effect upon CO2 and ethylene concentration. Bananas ripened with ethephon in suitable film packages had good eating quality and a longer shelf life than bananas ripened in air.

Open Access
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Abstract

Exposure to 40°C for 72 hours did not promote ripening of ¾ developed ‘Dwarf Cavendish’ bananas (Musa sp.) which had a preclimacteric period of >32 days at 21°. Bananas which were more advanced in physiological age and hence had a shorter preclimacteric period were more sensitive to heat. Twelve to 24 hours exposure to 40° promoted rapid ripening of bananas with an advanced physiological age. Treatment with 0.01 to 0.10 ppm ethylene at 40° created similar effects after shorter periods of exposure in comparison to the control. Internal ethylene was not increased by high temperature but was increased roughly 0.1 ppm by 0.1-ppm external ethylene treatment. Green bananas were more sensitive to ethylene at 40° than at 21°.

Open Access
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Abstract

Daminozide (butanedioic acid mono-(2,2-dimethylhydrazide)-treated ‘McIntosh’ apples (Malus domestica Borkh.) harvested at the preclimacteric stage did not soften in 7-½ months of controiled-atmosphere (CA) storage with <1 ppm ethylene in the atmosphere. These apples were satisfactorily firm and of acceptable-to-good quality after storage plus 7 days at 21°C. Apples from all other treatments were softer and had inferior quality. Control fruit harvested at the preclimacteric stage and stored in CA with a low ethylene level (<2.6 ppm) was also slightly firmer than similar fruit stored in CA with high ethylene (10 or 500 ppm). With a high ethylene level (500 ppm) in CA, daminozide-treated fruit was not firmer than control fruit and had more ‘McIntosh’ breakdown during the 7-day holding period after storage.

Open Access
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Abstract

High temperature (40°C) for 2 and 4 days lowered the acidity of 4 cultivars of apples (Malus domestica Borkh.). The preheated fruit was firmer than the control during 2 to 4 weeks of holding at 21°. The treatment also accelerated the loss of chlorophyll from the fruit skin. The soluble solid content of the fruit was not affected. Apples after the heat treatment had a normal respiratory climacteric and normal ethylene production rates. Some feasibility of applying high temperature to improve apple quality seems to exist.

Open Access
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A high CO2 slow cooling CA storage procedure was developed for `McIntosh' apples (Malus domestica Borkh.). The apples were cooled from 18° to 3°C in 15 days in atmospheres containing a constant O2 at 2.5% and decreasing CO2 starting with 12% and ending at 3%. The results of several tests in a flow-through simulated CA storage system revealed that the new procedure was nearly as effective as rapid CA and was much more effective than traditional slow CA in preserving the firmness of `McIntosh' apples for up to 4 months of storage. Maintaining a constant CO2 either at 12% or 3% instead of gradually decreasing it from 12% to 3% during the slow cooling period resulted in more storage disorders or/and softer apples.

Free access
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Abstract

Good correlation was found between length of storage life of banana (Musa cavendishii Lambert cv. Dwarf Cavendish) and minimum treatment time required for ethylene ripening response at harvest. All test bananas responded to 24 hours or less of 10 ppm ethylene treatment. Based on 29 sample groups of greenhousegrown ‘Dwarf Cavendish’ bananas, a linear regression equation relating banana storage life in days in air at 21°C (as output Y) and minimum time in hours required for ripening response to 10 ppm ethylene (as input X) was obtained as Y = 4.59 + 1.25X. The 2 variables had a correlation coefficient of 0.92.

Open Access
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Abstract

‘Dwarf Cavendish’ bananas (Musa cavendishii, Lambert), which were pretreated with ethylene and stored 28 days in 1% O2 or in 1/10 atmospheric pressure at 14°C, remained green and firm until the end of storage, but started to ripen almost immediately after being placed in 21°C air without additional ethylene treatment. The bananas so treated and stored had normal eating quality when ripe. The key to success was a pretreatment with ethylene for a period of time equal to the minimum required to induce the ripening response. Longer periods of ethylene pretreatment caused bananas to ripen in storage. The data suggest ethylene inactivates a natural ripening inhibitor.

Open Access
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Abstract

The sensitivity of ‘Dwarf Cavendish’ bananas (Musa cavendishii, Lambert) to ethylene was affected by the physiological age of the fruit and by the composition of gases ambient to the fruit. Ethylene at a concentration of 0.1 ppm in air always shortened the length of the preclimacteric period at 21°C. Exogenous ethylene at concentrations of 0.015 − 0.05 ppm, which were lower than those of endogenous ethylene of the fruits, was effective with 2 out of 3 lots of bananas tested. Low O2 and high CO2 concentrations in the storage atmosphere reduced the sensitivity of bananas to ethylene. The minimum effective concentration of ethylene in a gas mixture containing 4% O2 and 7% CO2 was between 0.1 and 0.5 ppm for bananas with highly advanced maturity and was between 0.5 and 1.0 ppm for bananas with less advanced maturity.

Open Access
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This study was designed to quantify the responses of leaf expansion, stomatal conductance, and transpiration of four genotypes of vegetable amaranth [Amaranthus tricolor L. (Hin Choi), A. tricolor L. (Co. 2), A. blitum L. (WS80-192), and A. cruentus L. (RRC 1027)] to soil drying. Two greenhouse experiments were conducted during 1999 and 2000. Soil water status was expressed as the fraction of transpirable soil water (FTSW). Leaf expansion rates, stomatal conductances, and transpiration rates of the stressed plants were determined relative to those of nonstressed plants, and expressed as relative leaf expansion (RLE), relative stomatal conductance (RSC), and relative transpiration (RT), respectively. The rate of soil water extraction differed among genotypes, with RRC 1027 depleting soil water fastest and Hin Choi slowest. Whereas in 1999 all genotypes were equally efficient in soil water use, RRC 1027 extracted a greater volume of transpirable soil water than the other genotypes in 2000. The responses of RLE, RSC, and RT to FTSW were well described by linear-plateau models which allowed calculation of soil-water thresholds for leaf expansion (CL), stomatal conductance (CS), and transpiration (CT). Values for CL were higher than for CS and CT. CL was similar for the four genotypes in each year, whereas, CS and CT differed among genotypes. CS and CT was lowest for Hin Choi and highest for WS80-192. Differences of CL, CS, and CT between the two experiments might have been due to the different soils used in the experiments and the different evaporative demands during the drought cycles. Under drought stress, the reduction of transpiration of vegetable amaranth was due mainly to reduction of stomatal conductance, not to reduction of leaf expansion. The relative reduction of dry weight caused by drought stress was positively correlated with CS or CT across the four genotypes. Variation in CS and CT among amaranth genotypes revealed different responses to drought stress, which could make them suitable for different drought situations.

Free access
Author:

Abstract

Ten to 100 ppm ethylene in air inhibited the development of superficial senescent spots on ripe bananas (Musa cavendishii Lambert cv. Valery). The ethylene did not affect the respiration rate but accelerated softening of the partially ripe or ripe bananas at 21°C. Six days of continuous exposure to 10 ppm ethylene did not affect the eating quality of bananas but 9 days of exposure slightly lowered the quality. Ethylene did not inhibit anthracnose (Gloeosporium masarum Cke. & Mass.) growth on banana fruit or on petri dish culture. Dipping ripe bananas in 100 to 1000 ppm (2 chloroethyl)phosphonic acid (ethephon) did not inhibit the senescent spot development. Brief dipping in silver nitrate solution (50 mg/liter) counteracted the ethylene effect.

Open Access