Search Results
Abstract
Rates of ethylene production, respiration, and yellowing of broccoli (Brassica oleracea L. Italica group) at 20°C were reduced by an aminoethoxy analog of rhizobitoxine (AAR) [L-2-arnino-4-(2-arnino-ethoxy)-trans-3-butenoic acid] and by sodium benzoate (SB). Loss of chlorophyll and ethylene production were retarded by concn of 5 × 10-3M of AAR; at concn of 10-3M or 5 × 10-4M, the retardation was less pronounced. Yellowing and ethylene production were markedly reduced by SB at concentrations of 0.01M, 0.05M, or 0.1M. However, the latter two concentrations caused chemical injury and off-odor which resulted in unsalable quality. The data suggest that senescence of broccoli is related to ethylene production and that senescence can be retarded by inhibiting ethylene production.
Abstract
Exposure of sweet peppers (Capsicum annuum L.) to 30% CO2 for 6 days at 13°C immediately after harvest retarded wall softening and ripening in air at 13° but caused the subsequent development of severe calyx injury and decay at 20°. Slight to moderate calyx injury was induced by a 6-day exposure to 20% CO2. Severity of the injury was greater when the CO2 was used with 3% O2 as compared to 21% O2. Injury was not induced by a 6-day treatment with 10% CO2. When stored at 13°, quality of peppers with this treatment was superior after 10 days, but inferior after 20 days to that of peppers kept continuously in an atmosphere of 5% CO2 and 3% O2. Benefits obtained from the 3-day elevated CO2 treatment (10 to 30%) were nullified after 10 days’ storage at 13°. Ethylene production was greatly inhibited in high CO2 atmospheres but rose immediately after transfer to air. Red color development, chlorophyll degradation, and ascorbic acid accumulation were retarded only in the presence of high CO2.
Abstract
High storage humidities, wax, and polyethylene film as bin-liners were compared for minimizing loss in storage life and preventing fruit shrivel during storage prior to packaging for market of pear (Pyrus communis L. cv. d’Anjou). Lining the sides and covering the top of bins with 1.25-mil polyethylene film was the most beneficial in preventing fruit shrivel without adversely delaying cooling. Enclosing pears in film bin bags also controlled moisture loss but was detrimental to rapid removal of field heat. Waxing the fruit or covering only the top of bins with film did not reduce the cooling rate but were ineffective in preventing excessive moisture loss. Introduction of water vapor to maintain high humidity markedly reduced moisture loss but caused ice formation on the fruit and storage room floor.
Abstract
Addition of rhizbitoxin analogs to holding solutions extended vase life of bulbous iris flowers (Iris xiphium L), daffodils (Narcissus pseudo-narcissus L.) and chrysanthemums (Chrysanthemum morifolium Ramat). Sodium benzoate also increased vase life of daffodils butnot of irises and chrysanthemums. Isopentenyl adenosine delayed senesence of irises but not of chrysanthemums. None of the chemicals tested extended the vase life of roses (Rosa hybrida L). Ethylene production in rose petal tissue was reduced by rhizobitoxine analogs indicating that roses do not have a rhizobitoxine-resistant ethylene producing system. Results suggested that either roses are sensitive to low levels of ethylene or their senescence is triggered by factors other than ethylene.
Abstract
Fruit of ‘Spartan’ apple (Malus domestica Borkh.) trees treated in April with paclobutrazol maintained greater firmness and had less internal breakdown than control fruit after 7 months in storage at 0°C. However, ACC level, ethylene production, respiration, soluble solids, sorbitol, fructose, glucose, sucrose, and malic acid content of the fruit after 0° storage and during ripening at 20° were not affected. Chemical names used: β-[(4-chlorophenyl)methyl]-α-(1,1-dimethylethyl)-1H- 1,2,4-triazole-1-ethanol (paclobutrazol); 1-aminocyclopropane-1-carboxylic acid (ACC).
Abstract
Treatment with 500 ppm ethylene for 24 hr or with 4000 ppm Ethrel (2-chloro-ethanephosphonic acid) dip for 30 sec resulted in ‘Anjou’ pears attaining full ripeness without a concomitant change in respiratory activity. A decrease in flesh firmness and increases in protein nitrogen and soluble pectin occurred, even though the fruit remained in the preclimacteric condition. This was shown by a positive response in rate of respiration to ethylene at the fully ripe stage. Continuous, 48- and 24-hr treatments resulted in comparable rates of ripening. However, while the continuous and 48-hr treatments induced the climacteric rise in respiration, the 24-hr exposure failed to do so. The effect of ethylene on respiration is independent from its effect on the initiation of ripening; a respiratory response probably requires a higher concentration or longer exposure to ethylene than does a ripening response.
Abstract
Treatment of ‘d'Anjou’ pears (Pyrus communis L.) with high CO2 atmosphere for a short period immediately following harvest prolonged storage life, retarded ethylene production, delayed the climacteric rise in respiration, reduced loss of malic acid, suppressed increase in protein N, retained firmness, quality and the capacity to ripen after long storage. Treatment with 12% CO2 for 2 or 4 weeks provided the best results without injury.
Abstract
Continuous exposure of pears to 7.2°C (night) - 21.1°C (day) for 2 days or 10°C - 21.1°C for 9 days or 7.2°C - 26.7°C for 21 days induced the physiological disorder, premature ripening, during the month immediately preceding normal harvest. During the same period, premature ripening did not develop with temp exposures of 12.8°C - 21.1°C or with 7.2°C - 32.2°C. Cool temp 6 to 9 weeks prior to harvest may also cause premature ripening to occur but the fruit will recover to normal behavior if subsequent temp are above the threshold level.
Abstract
Difference in optical density (∆OD) of intact ‘Bartlett’ pears (Pyrus communis L.) between wavelengths 690 and 740 nm was measured at harvest and during ripening with a single-beam multiwavelength spectrophotometer. The ∆OD indicated the status of ripeness and detected core breakdown of ‘Bartlett’ pears nondestructively. The ∆OD decreased consistently with ripening and was associated with softening, climacteric rise in respiration, and ethylene production. The ∆OD increased in pears with core breakdown even before external symptoms were visible.
Abstract
Small ‘d’Anjou’ pears (Pyrus communis L.) tend to be more susceptible to friction discoloration than the large fruits. Susceptibility to friction discoloration decreased with maturity but increased with duration of storage. Phenolic substances which are associated with friction discoloration and which serve as the substrate for polyphenoloxidase also declined with maturity and accumulated in storage. However, polyphenoloxidase activities increased with maturity and decreased during storage. The accumulation of phenolic compounds may be a result of the low polyphenoloxidase activities in storage.