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Ki-Cheol Son, Y. Chae, and Y. Lee

During the aging of H. syriacus flower, biosynthetic pathways of ethylene and polyamines, their interactions, and their effects on senescence were investigated. The evolution of ethylene in ephemeral flower was rapidly increased immediately after initiation of in-rolling of corolla at which EFE activity became maximum peak. After that, EFE activity was gradually decreased even though the aging was continued. Ethylene production was, however, slightly inhibited by the treatments of AOA and putrescine. The activity of ACC synthase and SAM decarboxylase were most rapidly increased at the time of 36th hrs. The contents of ACC and MACC were gradually increased from the early stage. However, ACC contents was decreased at the final stage but MACC was continuously increased. In normal condition, endogenous level of polyamines exists in the order of putrescine>spermidine>spermine. Putrescine was reduced from the initial point of aging, but spermidine and spermine were reduced from the middle and final stage of aging, respectively.

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Ni Lee and Hazel Y. Wetzstein

Plantlets were recovered from axillary bud cultures of muscadine grape (Vitis rotundifolia, `Summit'). Nodal segments 0.5 to 1.0 cm long were cultured in Murashige and Skoog (MS) basal medium supplemented with 5, 10, 20, or 40 μm BA. Best total shoot production was obtained with 10 μm BA; with higher BA levels, shoots were unexpanded and exhibited high mortalities. MS medium supplemented with IBA enhanced rooting by increasing rooting percentage and number per plantlet. Shoots previously proliferated on medium with 5 μm BA rooted significantly better than those multiplied on 10 μM BA. Shoot vigor during rooting was greater in shoots proliferated on 5 vs. 10 μm BA. Root development was not significantly affected by liquid vs. agar-solidifted medium or shoot length. Chemical names used: N-(phenylmethyl) -1H-purin-6-amine (BA), 1H-indole-3-butyric acid (IBA).

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Y.S. Hwang, J.C. Lee, and B.J. Lee

Oriental pear, `Niitaka', often suffers from skin and/or core browning when storage duration is extended. Skin browning occurred in aged fruit differs from browning disorder occurred at the early stage of low temperature storage (within 1 month), which is dark in color. This disorder can be inhibited by temperature conditioning through stacking fruit under shade for 7 days. Unlike dark browning disorder, fruit affected by light browning disorder often develops core browning. Also, when the duration of temperature conditioning is extended, light browning disorder occurred more rapidly even at 0 °C. In this experiment, the effect of external application of ethylene and ethylene scrubbing in storage environment was examined. Light browning disorder increased when fruit were wrapped with polyethylene film (30 μm) and the application of ethylene scrubber effectively decreased this disorder. Skin peeling was also observed in disordered fruit. The application of ethylene resulted in the increase of light browning on skin and core browning. Thus, both disorders seemed to be involved with senescence. The involvement of ethylene on both disorders will be further discussed.

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W.S. Lee, J.C. Lee, and Y.S. Hwang

The coloration of grape berries depends on the anthocyanin synthesis during maturation. The quality of berries is often decreased due to the poor color development when berries are grown under unfavorable environments and/or inadequate internal factors are involved. It has been well-known that the level of ABA at ripening is closely associated with anthocyanin synthesis; thus, the external application of ABA results in the increase of anthocyanin content even in berries grown under favorable conditions. However, the agricultural use of natural ABA is not possible because of high prices. This experiment was conducted to study the potential of STC-4771 as a substitute for ABA. The effect of STC-4771 was studied in `Kyoho', `Pione', and `Delaware' grapes. Chemicals were applied when ≈10% of berries in a cluster were colored. In `Kyoho', anthocyanin synthesis was enhanced at a concentration of 100 mg/L and there was a trend in color enhancement in `Pione', regardless of treatment concentration, between 10 to 40 mg/L. However, no clear effect was found in `Delaware' at 50 to 100 mg/L. In an in vitro experiment, anthocyanin was only increased when an adequate amount of sucrose (0.6 m) was added in the incubation medium under light. Natural ABA effectively increased the anthocyanin content of berry segments even under shading condition through four bagging materials, but no effect was confirmed in STC treatment.

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Y.J. Yang and K.A. Lee

Garlic (Allium stivum L. cv. `Seosan') grown in Kyungbuk, Korea were harvested on June 1999 and dried in the field for 2 to 3 days. Bulbs were selected for uniformity in size and maturity and divided into two groups. One group was further dried in the shade at 25 °C for curing before storage at 0 °C. The other group was stored at 0 °C immediately without additional drying. Respiration of garlic bulbs dried additionally for 3 months was low, ranging from 1.5 to 3.0 CO2 mL/kg per h for 95 days in storage; ethylene was not detected until 60 days in storage. Non-curing samples showed rapid increase of carbon dioxide production after 50 days of storage, this might be related to incidence of fungal decay. Ethylene showed maximum value at 45 days in storage, thereafter remained level of 5.6-6.3 μL/kg per h. All treatments did not show sprouting during storage period, but incidence of decay was significantly reduced by additional drying. The beneficial effect of curing for 3 months at 25 °C was maintenance of low water content in garlic bulbs, which resulted in reduction of decay.

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Kyung Ku Shim, Y.M. Ha, J.B. Lee, K.O. Byun, Y. Youn, E.R. Noh, and H.R. Park

New cultivars, `SKK 1' and `SKK 2', of Korean mountain ash (Sorbus alnifolia) that had superior morphological features as woody landscape plants were selected from 5000 seedlings of Sorbus alnifolia. Two clones with genetic variation were selected from 1983 to 1994 as landscape plants with large leaf and unique tree form: `SKK 1', which had large leaf and flower, and `SKK 2', with semi-weeping tree form. New selected cultivars of S. alnifolia were successfully grafted and inherited their mother characteristics. Sorbus alnifolia was difficult to propagate by cutting. Therefore, in vitro propagation methods might be used to propagate the superior cultivars. Shoots with apical and axillary buds were excised from 1-year-old seedlings. The explants were cultured on WPM supplemented with 0.5 mg/L BA. Shoots formed from initial cultures were subcultured at ≈4-week intervals onto the same media. To know the best hormone concentration in shoot multiplication, 0.1–3.0 mg/L of BA and 0.1–1.0 mg/L of zeatin were added to each WPM and MS media. The best shoot proliferation and elongation were obtained on MS medium with 1.0 mg/L BA from the whole shoot with the callus-like tissue, whereas the worst results were obtained from shoot tip. A 13-fold proliferation rate was achieved every 4 weeks.

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Hong Y. Yoon, Sung R. Kim, Seung W. Lee, and In S. Chung

The effects of various media, varying concentrations of sucrose, plant growth regulators, and inorganic salts such as KNO3, KH2PO4 and NH4NO3 on callus Formation and anthocyanin synthesis in carrot cell culture were studied. The greatest calli and anthocyanin pigments were obtained by SH and Nitsch & Nitsch medium, respectively. Nitsch & Nitsch medium supplemented with 55g/l sucrose, 0.2g/l NAA and 0.1g/l BA was effective for both callus and anthocyanin production. Anthocyanin synthesis was accelerated by increasing concentration of KNO3, while suppressed by NH4NO3. However, KH2PO4 promoted anthocyanin synthesis at half strength. These results suggest that physiological factors on anthocyanin production by plant cell culture could provide the possibility of application to other crops for secondary metabolites production and mass production system establishment of anthocyanin as an important natural pigment in cosmetic and food industry.

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Mingbo Qin, Chiwon W. Lee, Alex Y. Borovkov, and Murray E. Duysen

A study was initiated to characterize key enzymes that influence sweetness in carrot (Daucus carota L.) roots. Sucrose synthase (SS), sucrose phosphate synthase (SPS), and UDP-glucose pyrophosphorylase (UDPL) genes were isolated from potato (Solanum tuberosum L.) and cloned in an anti-sense orientation into Agrobacterium tumefaciens Bin19, which has a CaMV 35S promoter. Seedling hypocotyl sections of selected carrot lines were pre-incubated on B5 medium for 2 days, co-cultivated with A. tumefaciens Bin 19 for additional 3 days, and then transferred to a modified B5 medium containing 50 g/mL kanamycin and 400 g/mL carbenicillin. In 4 weeks, 18.6%, 33.3%, and 26.7% of the cultures from a breeding line (W204-C) were found to be transformed, respectively, with SS, SPS, and UDPL as determined by kanamycin resistance. In contrast, no kanamycin-resistant calli were obtained from a commercial cultivar (Navajo) in these transformation studies. The transformed calli proliferated in the medium containing 50 g/mL kanamycin and 400 g/mL carbenicillin, whereas non-transformed calli died in the same medium. These transformed calli are currently being used to regenerate plants via asexual embryogenesis using a suspension culture. The influence of these additional genes on sugar metabolism and accumulation in root tissues of transformed carrots will be characterized in the future.

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Ming-Wei S. Kao, Floyd Woods, William A. Dozier, Robert C. Ebel, Chang Y. Lee, and Jun Bae Jee

The health status of Alabama's population ranks above the national average with respect to the prevalence of poor overall health indicators. Consumer knowledge of the health benefits of consumption of fresh fruit is lacking. The compositional and nutritional qualities of fruit are highly variable among states with different climate, soil, and other environmental conditions. Compositional and nutritional data of fresh fruit that reflect Alabama growing conditions is limited. Commercially fully ripened kiwi fruit (Actinidia deliciosa cvs. Fitzgerald and Hayward) were compared for fruit quality (pH, TA, °Brix, °Brix/TA, and soluble sugars), and antioxidant properties; Vitamin C (reduced, oxidized, and total), Vitamin C Equivalent Antioxidant Capacity (VCEAC), ferric reducing antioxidant power (FRAP), DPPH radical scavenging activity, total phenolics, and flavonoids. In general, `Fitzgerald' ranked higher in overall fruit quality and antioxidant properties when compared to `Hayward'.