`Flavortop' nectarines [Prunus persica (L.) Batsch] were stored at -0.5C or 3C for 0, 1, 2, 3, or 4 weeks, after which the fruit was ripened at 15C. After ripening, fruit samples were tested daily or every second day for extractable juice, internal conductivity, and woolliness. The change in the percentage of extractable juice during ripening differed very little among the five storage periods. A rapid increase in internal conductivity occurred during ripening in fruit with or without cold storage, but the onset of the increase was advanced with longer cold-storage periods. No woolliness developed in fruit not placed in cold storage or in fruit cold-stored for 1 or 2 weeks at - 0.5C or 3C. Woolliness only developed during ripening of fruit cold-stored for 3 or 4 weeks at -0.5C or 3C. Incidence of woolliness increased to high levels during ripening and decreased thereafter to no woolly fruit by the 11th day. The lowest values for extractable juice coincided with the highest incidence of woolly fruit. Fruit stored for 4 weeks took longer to pass the woolliness stage. At the end of the ripening. period, cold-stored fruit were similar in appearance and juiciness to those ripened without cold storage. Nectarines stored at 3C generally developed woolliness earlier, had a lower incidence of woolliness, and took longer to overcome the problem than fruit stored at -0.5C. Incidence of browning of the mesocarp tissue was greater at 3C than at -0.5C.
L.J. von Mollendorff, G. Jacobs, and O.T. de Villiers
Jinwook Lee, In-Kyu Kang, Jacqueline F. Nock, and Christopher B. Watkins
’, ‘Golden Delicious’, and ‘Bisbee Delicious’ apples ( McArtney et al., 2008 ; Yuan and Li, 2008 ; Watkins et al., 2010 ). In addition, preharvest treatment can retain fruit firmness of ‘Gamhong’ apples during cold storage ( Yoo et al., 2013 ) and of
Ahmad Sattar Khan and Zora Singh
postharvest application of polyamines ( Serrano et al., 2003 ), aminoethoxyvinylglycine ( Jobling et al., 2003 ), and 1-methylcyclopropene (1-MCP) ( Khan and Singh, 2007 ; Watkins, 2006 ); edible coating ( Navarro et al., 2005 ); cold storage ( Robertson et
Bahman Shafii and Danny L. Barney
Trials were conducted to determine the effects of air drying and cold storage on black huckleberry (Vaccinium membranaceum Douglas ex Hooker) seeds. Treatments included fresh seeds, seeds air-dried for 7 days, and those air-dried and stored at 2 to 3 °C for either 1 or 7 years. Germination was measured every 7 days. The time course of germination was modeled using a logistic growth curve from which days to 50% germination (T50), germination rate index, and maximum germination percentages were estimated. Germination curves of dried and of dried and cold-stored seeds were significantly different from that of fresh seeds. Seeds stored for 1 or 7 years had germination percentages similar to those for the fresh, nondried seeds. Air drying for 7 days reduced the maximum germination percentage from 73% to 59% (fresh seeds). This induced dormancy was gradually lost during cold storage of dry seeds. Cold storage of air-dried seeds was an effective method for preserving V. membranaceum germplasm for at least 7 years.
W.R. Miller and R.E. McDonald
Carambolas (Averrhoa carambola L.) must be treated with an approved insect quarantine procedure such as cold treatment before shipment to certain markets. Condition and quality of mature-green (MG) and slightly yellow (SY) fruit were determined after they were: 1) treated with ethylene at 0.1 ml·L-1 for 48 hours (C2H4), 2) subjected to cold treatment (CT) at 1 °C for 15 days, and 3) held in storage at 5 °C for 7 days plus 3 days at 15 °C. Ethylene-treated fruit were softer and yellowness was enhanced compared with non-C2H4-treated fruit. MG fruit were firmer and lost more mass following CT and storage than SY fruit. C2H4 treatment increased the severity of peel scald, stem-end breakdown (SEB), and fin browning but had no effect on pitting. CT increased the severity of scald and pitting, and the severity of SEB, but did not affect fin browning. Peel scald, pitting, SEB, and fin browning were more severe in MG than in SY fruit at the final evaluation. C2H4-treated fruit had lower total soluble solids concentration, higher titratable acidity and pH, and a less preferred flavor and texture than control fruit. We conclude that carambola fruit should be selected at harvest at the slight-yellow stage (3% to 25% of surface area) instead of at the mature-green stage. Fruit to be cold-stored should not be C2H4 treated due to enhanced mold development and severity of SEB.
Rachel Leisso, Ines Hanrahan, and Jim Mattheis
, J.J. Hoover, E.E. Bedford, D.S. 2002 Storage potential of cold-hardy apple cultivars J. Amer. Pomol. Soc. 56 34 45 Etienne, A. Génard, M. Lobit, P. Mbeguié-A-Mbéguié, D. Bugaud, C. 2013 What controls fleshy fruit acidity? A review of malate and
Rafael Alique, José P. Zamorano, Ma Luisa Calvo, Carmen Merodio, and José L. De la Plaza
`Fino de Jete' cherimoya fruit were stored at 20, 10, 8, or 6C, 80% relative humidity. Two rises of CO2 production and an ethylene rise following the first peak of respiration were obtained in fruit held at 20C. The ripe stage coincided with the onset of the second respiratory rise. Soluble sugar and organic acid concentration were maximal, and flesh firmness was 18 N in ripe fruit. Lower temperature reduced respiration rate and ethylene production; however, some stimulation of ethylene synthesis was observed at 10C. Cherimoyas ripened to edible condition during 6 days at 10C, but fruit maintained at 8C for up to 12 days required transfer to 20C to ripen properly. Our results suggest that high increases in CO2 are not sufficient to complete cherimoya fruit ripening without the concurrent rise in ethylene production. Citric acid accumulation, inhibition of ethylene synthesis, and reduced accumulation of sucrose were observed during storage at 6C. Removal to 20C after 12 days at 6C resulted in no ripening, almost complete inhibition of ethylene synthesis, and severe skin browning. Thus, 8C is the lowest tolerable temperature for prolonged cold storage of cherimoya `Fino de Jete'. Fruit can be held at 8C for up to 12 days without damage from chilling injury.
David Garner, Carlos H. Crisosto, and Eric Otieza
`Snow King' peaches (Prunus persica) harvested at commercial maturity were subjected to different carbon dioxide (CO2) and oxygen (O2) atmosphere combinations for a 2-week simulated transportation [0 °C (32 °F)] period after 1 week of cold storage in air (0 °C). In 1998, air or 5%, 10%, 15%, or 20% CO2 combined with 3% or 6% O2 were used during shipment. The trial was repeated in 1999, but for this year half of the fruit were treated with a 50 mg·L-1 (ppm) aminoethoxyvinylglycine (AVG) postharvest dip before storage and simulated shipment. In addition, O2 levels during simulated shipment were reduced to 1.5% and 3%. At harvest and after the 2-week simulated shipment, fruit flesh firmness, soluble solids concentration (SSC), titratable acidity (TA), and chilling injury (CI) were evaluated. For both years, there were no significant differences in quality attributes among the different treatments after the simulated shipment period. SSC and TA did not change during 5 days postshipment ripening at 20 °C (68 °F). In 1998 all treatments softened rapidly during the postshipment ripening at 20 °C, and were ready to eat [13 N (1 N = 0.225 lb force)] after 3 days. In 1999, both the high CO2 atmospheres during shipment and the AVG postharvest dip slowed the rate of softening during subsequent ripening at 20 °C. With respect to fruit softening, there was significant interaction between storage atmosphere and AVG treatment. AVG-treated fruit shipped under a 20% CO2 + 3% O2 atmosphere did not soften to the transfer point (firmness = 27 N) within our 5-day ripening period, while fruit not treated with AVG and shipped under the same atmosphere softened to the transfer point in 3 days. Control fruit (no AVG + air shipment) softened to the transfer point in 2 days. Our previous work found that when white flesh peaches soften to less than 27 N firmness they become very susceptible to impact bruise injury during retail distribution. We call this critical level of fruit flesh firmness the transfer point. Symptoms of CI, low O2, or high CO2 injury were not observed in any treatment in either year.
Mariya V. Khodakovskaya, Richard J. McAvoy*, Hao Wu, and Yi Li
It has been reported that constitutive expression of the fatty acid desaturase enzyme increased the trienoic fatty acid content of thylakoid membranes in transgenic tobacco, allowing the membranes to remain fluid under cold conditions. While increased cold tolerance resulted from this genetic modification, plants with a constitutively expressed desaturase enzyme would not be particularly well suited for growth under warm temperatures. To increase the ability of plants to tolerate prolonged cold-storage and still perform under greenhouse production conditions (25 °C), a unique cold-inducible genetic construct was cloned and tested. The FAD7 gene, which encodes an omega-3-fatty acid desaturase enzyme, was put under the control of a cold-inducible promoter (cor15a) from Arabidopsis thaliana. Transgenic petunia plants (cv, Marco Polo Odyssey) harboring cor15a:FAD7 were established and conformed by PCR and Southern analysis. Therefore in our study, FAD7 gene expression was induced by exposure to cold temperatures and down regulated under normal growing conditions. RT-PCR indicated a marked increase in FAD7 expression between transgenic plants exposed to a short (3 days) cold treatment prior to long-term cold storage and those that did not receive a cold induction treatment. Transgenic and wild-type plants were induced in cold (3 °C) for 3 days, returned for normal greenhouse conditions for 5 days and then subjected 3 weeks of continuous cold storage. It was observed that two out of eight transgenic lines showed superior cold tolerance relative to wild-type petunia plants. Additionally, plants that showed cold tolerance completely recovered; growing and flowering normally when returned to the 25 °C greenhouse conditions.
M.R. Pooler and P.W. Simon
The effects of cold storage, photoperiod, and growth temperature on flowering incidence in four clones of garlic (Allium sativum L.) were studied. While flowering percentage was influenced most by clone, interactions with photoperiod, growth temperature, and storage occurred. Clone R81 flowered equally well in all conditions, whereas flowering percentage of clones D129, D130, and PI485592 was reduced by cold (4C) storage of either bulbs or plants, long (16-h) photoperiod, and at 18C relative to 10C. The highest flowering percentage in all garlic clones was achieved by growing plants at 10C under short (9- to 10-h) photoperiod with no cold storage of bulbs before planting.