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Robert L. Wample and Andy Bary

Cold-hardiness evaluations and soluble and insoluble-nonstructural carbohydrate analysis of dormant Vitis vinifera L. cv. Cabernet Sauvignon buds and cane tissue indicate a positive relationship between soluble carbohydrates and primary bud cold hardiness. Seasonal variations in soluble and insoluble carbohydrates appear to be related to changes in air temperatures and the dormancy status of the tissues. No differences were found in bud cold hardiness and only limited differences in carbohydrate levels of buds or stem tissues collected over 3 years from early harvest, normal harvest, or unharvested vines. These findings contrast with the widely held opinion that delayed harvest or failure to remove fruit results in reduced cold hardiness as a consequence of low storage carbohydrate content of the plants.

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Karen L.B. Gast

40 POSTER SESSION 3 (Abstr. 092-104) Postharvest Physiology/Storage/Food Science Monday, 24 July, 1:00-2:00 p.m.

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James A. Okeyo and Mosbah M. Kushad

`Atlantic', `BelRus', `Kennebec', and `Superior' potatoes (Solarium tuberosum L.) were evaluated for ascorbic acid, soluble protein, and sugar content (reducing and nonreducing) at harvest, after 6 weeks of storage at 3C, and after 2 weeks of reconditioning at 25C. At harvest, ascorbic acid and soluble protein contents varied among the cultivars, with `Superior' containing the highest ascorbic acid (154 mg/100 g dry weight) and soluble protein content (46.4 mg·g−1 dry weight). Cold storage resulted in a drastic reduction (±50%) in ascorbic acid content in all four cultivars. Ascorbic acid also decreased during reconditioning of tubers, but the reduction was less than during cold storage. In contrast, soluble protein contents were not influenced significantly by cold storage or reconditioning, except for `BelRus' and `Kennebec', which had less protein after reconditioning. At harvest, glucose, fructose, and sucrose contents were at similar levels in all cultivars, except for fructose in `Kennebec', which was more than 2-fold higher. `Kennebec' also had a significantly lower specific gravity than the other cultivars. However, unlike the other cultivars, reconditioning of `Kennebec' tubers did not affect its specific gravity or total sugar content. Data suggest that `Kennebec's' poor processing quality may have resulted from a combination of low specific gravity and high total sugar content.

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Fumiomi Takeda Takeda, Stan Hokanson*, John Enns, Penelope Perkins-Veazie, and Harry Swartz

`Chandler' strawberry plants were propagated in tissue culture and grown from April to August in a protected environment to produce stolons. July-harvested daughter plants were stuck in cell packs with rooting media and placed under mist sprinklers, or cold stored at 2 °C for 42 days. Among the July transplants, some were kept in the greenhouse until field planting (14 Sept.) and others were moved into a cold room on 14 August. Daughter plant size and position on the stolon affected rooting and quality of transplants. July-harvested daughter plants that were plugged and misted after being cold stored for 42 days developed fewer roots than daughter plants plugged immediately after detaching from mother plants in July or August. In the field, transplants produced from daughter plants harvested in July and cold stored for 42 days developed more stolons than transplants from July- and August-harvested daughters that were not exposed to cold storage treatments. Larger daughter plants produced more branch crowns than did smaller daughter plants during the fall. All transplants from daughter plants harvested in July and propagated without cold treatment bloomed by November. Fruit production ranged from 521 to 703 g per plant. `Chandler' plants from daughter plants that weighed 10 g produced 10% greater yield than those that weighed <1.0 g. Plants generated from daughter plants plugged in July produced 26% more fruit than those plants plugged in August. Greenhouse soilless systems can be used to grow `Chandler' mother plants for generating runner tips and transplants for the annual plasticulture in colder climates. `Chandler' plants produced in July can yield a late fall crop under high tunnels and more fruit in the spring than August-plugged transplants

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Mark P. Kaczperski, Allan M. Armitage, and Pamela M. Lewis

Seed of Petunia × hybrida `Ultra White' were germinated in #406 plug trays at 2.5 C and at a light intensity of 100 μ mol s-1m-2 using a 24 or photoperiod. At germination, seedlings were grown under natural light conditions for 8 hrs (SD) or for 8 hrs with the photoperiod extended to 16 hrs (LD) using incandescent bulbs. At approximately the 6th leaf stage, seedlings were stored at 5 C in the dark or at 12 μ mol s-1m-2 and a 24 hr photoperiod for 0 to 21 days. After storage, plants were potted n 10 cm pots and grown to flowering in a greenhouse. Plants grown under SD to the 6th leaf stage with no cold treatment were shorter. flowered later and had more lateral branching than unstored LD plants. Storage at 5 C decreased time to flower of SD plants and increased branching of LD plants regardless of photoperiod during storage.

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Rick M. Bates and Alexander X. Niemiera

Shoot and root water potentials were determined for bare-root Norway maple (Acer platanoides L.) and washington hawthorn (Crataegus phaenopyrum Med.) seedlings subjected to shoot and root exposure treatments for six cold storage durations. Shoot and root water potentials for all exposure treatments and both species decreased with increased time in storage, and the greatest degree of water stress occurred during the first six weeks of storage. Maple shoot and root water potentials for the exposed shoot treatment were the same as the whole plant covered treatment. In contrast, hawthorn shoot and root water potentials for the exposed shoot treatment were the same as values for the roots exposed treatment. Based on these data, we conclude that desiccation sensitive species such as washington hawthorn require root and shoot protection to minimize water loss.

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Armida Rodriguez-Felix, Evelia Araiza-Lizarde, Monica A. Villegas-Ochoa, and Elsa Brineas-Taddei

Physico-chemical and physiological changes of `Flordaprince peach fruits harvested at different maturity stages were evaluated during low temperature storage. Harvested fruits were immediately classified into four different maturity stages based on red-skin color (I, 20%; II, 40%; III, 60%; and IV, 80%). Fruits were stored at 2 C (90% R.H.) for 0, 15, and 30 days. Following cold storage conditions, fruits were transferred to a 20 C room. Physico-chemical and physiological characteristics evaluated during storage included weight loss, firmness, pH, titratable acidity, skin color (hue), total soluble solids, respiration rate, and ethylene production. Weight loss increased (up to 40%) after 27 days storage at 2C. The fruits harvested at maturity stage I showed the lowest weight loss. Flesh firmness decreased significantly during storage at 2 C. Fruits from stages I and II had higher firmness than fruits harvested at stages III and IV. A significant change from green-yellow to red color was observed in fruits of the distinct maturity stages during storage at 20 C.

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Guy J. Hallman

Canistel [Pouteria campechiana (HBK.) Baehni] fruit were subjected to cold storage and hot-water immersion treatments known to kill immature Caribbean fruit flies [Anastrepha suspensa (Loew)] in other fruit. Cold storage at 1 or 3C for 17 days did not cause appreciable loss in canistel quality compared with fruit stored at the normal 10C. Unripe canistels immersed in water at 46C for 90 min or at 48C for 65 min, however, developed dark blotches on the peel and a 2- to 3-mm-thick layer under the peel that did not soften. Canistels were infested with Caribbean fruit flies and subjected to 1 or 3C storage for up to 14 days. The resulting lethality data were fitted to three probability density functions (PDF) to estimate the number of days required to achieve quarantine security (99.9968% dead). The normal and Gompertz PDFs gave some reasonable estimates, while the logistic PDF gave low estimates. At 1C, 14 days would be needed to achieve quarantine security, while at 3C a minimum of 15 days would be required. These estimates must be tested to determine if they are valid after a large amount of Caribbean fruit fly immatures is subjected to the treatments.

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Jan E.P. Debaene and I.L. Goldman

Raw onion extract contains organosulfur compounds that prevent aggregation of platelets in human blood plasma and influence onion pungency. Organosulfur compounds are volatile and may change concentration during storage. A study was conducted to determine 1) whether antiplatelet activity of filtered onion extract decreases during time in cold (4C) storage; and 2) correlations among antiplatelet activity, pyruvic acid content, and percent solids during time in cold storage. Two low-pungency genotypes (8155 and Exhibition) and two high-pungency (W420 and W434) genotypes were grown in replicated plots in two Wisconsin and two Oregon locations in 1994. Bulbs were evaluated for antiplatelet activity, percent solids, and pyruvic acid content at 40-day intervals after onion harvest. Significant differences were found for pyruvic acid content, solids, and antiplatelet activity among dates of sampling, genotypes, and locations. Mean pyruvic acid concentrations ranged from 6.4 μm·ml–1 of extract for Exhibition, to 8.0 μm·ml–1 of extract for W420. Mean solids concentrations ranged from 5.8 g/100 g for Exhibition to 11.4 g/100 g for W434. Antiplatelet activity averaged over all genotypes increased over 120 days and was positively correlated with percent solids and pyruvic acid content.

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W. Todd Watson, David N. Appel, Charles M. Kenerley, and Michael A. Arnold

Effects of washing and storing soil core samples of apple [Malus sylvestris (L.) Mill. var. domestica (Borkh.) Mansf. (syn. M. domestica Borkh. non Poir.)] roots were studied to determine root losses from processing samples. Root losses were assessed by measuring root lengths before and after elutriation and storage at 4 °C (39.2 °F). The accuracy of the automated root length scanner to measure individual fine roots [<1 mm (0.04 inch) diameter] of varying lengths was evaluated by first measuring roots, then cutting the roots into 2 to 3 cm (0.79 to 1.18 inch) lengths and rescanning. There was a significant relationship between the measurement of cut and noncut roots (r 2 = 0.93). Losses from elutriating samples with cut and noncut roots indicated a mean loss of50% for samples with cut roots and 34% for samples with noncut roots (P ≤ 0.01). Total mean root loss (elutriation loss of noncut roots and degradation loss in cold storage) for the 12-month period ranged from 34% at month 0% to 53% at month 12 (P ≤ 0.01). Mean root degradation losses from long-term cold storage ranged from 6% at month 1 to 19% at month 12 (P ≤ 0.01). No losses were identified for roots with diameters of 1 to 5 mm (0.04 to 0.20 inch) and 5 to 10 mm (0.20 to 0.39 inch). A data correction curve was developed to correct root length data (<1 mm) for root losses associated with processing of soil cores.