Journal of the Japanese Society for Horticultural Science
Online ISSN : 1880-358X
Print ISSN : 0013-7626
ISSN-L : 0013-7626
Volume 70, Issue 4
Displaying 1-21 of 21 articles from this issue
  • Hisashi Yamada, Junko Minami, Shoji Amano, Kazuomi Kadoya
    2001 Volume 70 Issue 4 Pages 409-415
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    The occurrence of watercore in 'Orin' apples (Malus pumila Mill. var. domestica Schneid.) was prevalent from late August to late September ; there was a significant correlation between watercore rating and maximum fruit temperature during late August. The watercore occurred in immature apples long before the increase of ethylene and 1-aminocyclopropane-1-carboxylic acid (ACC), indicating that the watercore observed in this study was early watercore. Membrane permeability increased from mid-August to mid-September and showed a significant correlation with watercore. The degree of watercore during late August was significantly correlated with flesh firmness, soluble solids content (SSC), total sugars, fructose, glucose in the inner flesh, and sorbitol but not with titratable acidity, starch, and sucrose. The seasonal changes in sorbitol content paralleled the incidence of watercore ; the coefficients of correlation between them were 0.881 and 0.827 for the inner and outer flesh tissue, respectively. These results indicate that the changes in physiological factors such as membrane permeability and sorbitol content in the fruit during summer play an important role in inducing early watercore in apples. We propose that the physiological mechanism of early watercore development in immature apples is similar to that of high temperature-induced watercore during maturation but differs from that of low temperature-promoted late watercore.
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  • Hideaki Takagi
    2001 Volume 70 Issue 4 Pages 416-423
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    When freshly mature seeds of Polygonatum odoratum Druce var. pluriflorum Ohwi were planted in October and grown outdoors, no radicle emerged until the next summer and no green shoot emerged until the second spring. Radicle emergence (germination) was induced by cold stratification, so that radicle dormancy was completely terminated by stratification at 5°C for 60 days. Radicle dormancy of nonchilled seeds was partially broken by treatment with 5 mM ethephon. The optimum temperature range for germination after the termination of radicle dormancy was 17 to 25°C. The cold stratification of seeds, removed from fruits, improved germination than a similar treatment on intact fruits. Air-drying seeds for about a week before cold stratification had little effect on their germination. Seeds kept moist at 21°C after the termination of radicle dormancy almost stopped growing after 90 days of incubation because the epicotyl became dormant (epicotyl dormancy). Hence, no green shoot emerged aboveground unless the seedlings were chilled again to terminate epicotyl dormancy. Therefore, the type of dormancy in P. odoratum seeds resembles double dormancy described by Barton and Schroeder (1942). The optimum temperature range for shoot emergence after the termination of epicotyl dormancy was 17 to 29°C. Warm stratification after cold stratification and exposure to a second chilling greatly affected the time shoots emerged. Higher percentages of early and total shoot emergence were obtained when seedlings were kept either at 21°C for 120 days after the termination of radicle dormancy and then chilled at 5°C for 90 days to terminate epicotyl dormancy or kept at 21°C for 90 days and then chilled at 5°C for 120 days.
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  • Hideaki Takagi
    2001 Volume 70 Issue 4 Pages 424-430
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    When freshly harvested mature seeds of Polygonatum macranthum Koidz. were planted in October and grown outdoors, no radicle emerged until the following summer and no shoot emerged until the second spring. Radicle emergence was induced by chilling moist seeds at 17°C or below ; radicle dormancy was completely terminated by stratification at 5°C for 60 dyas. The optimum temperature range for germination after the termination of radicle dormancy was about 21°C. The cold stratification of excised seeds improved germination over a similar treatment on intact fruits. Air-drying seeds for about 3 days before cold stratification delayed germination. Seeds, kept moist at 21°C after the termination of radicle dormancy, almost stopped growing after 60 dyas of incubation because the epicotyl became dormant. In this case, no shoot emerged unless the seedlings were chilled again to terminate epicotyl dormancy. Therefore, the type of dormancy in P. macranthum seeds resembles the one in P. odoratum (Takagi, 2001). The optimum temperature range for shoot emergence after the termination of epicotyl dormancy was 25 to 29°C. Warm stratification after cold stratification and exposure to a second chilling greatly affected the time shoots emerged. Higher percentages of early and total shoot emergence were obtained when seedlings were kept at 21°C for 120 days after the termination of radicle dormancy and then chilled at 5°C for 90 days to terminate epicotyl dormancy.
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  • Masahito Shimonaka, Takashi Hosoki, Motonori Tomita, Yoshimasa Yasumur ...
    2001 Volume 70 Issue 4 Pages 431-437
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    For the purpose of establishing protoplast culture systems in Japanese bunching onion (Allium fistulosum L.), based on BDS inorganic salts (Dunstan and Short, 1977), nutrient media suitable for protoplast culture were investigated. The optimum cell division was achieved with 5 mM potassium nitrate and a combination of 2μM 2, 4-dichlorophenoxyacetic acid (2, 4-D) and 0.2 or 1 μM 6-benzylaminopurine (BAP). The suitable osmolality for protoplast culture was around 0.60 osmol·kg-1, whereas a combination of 0.2 M sucrose and 0.2 M glucose accelerated cell division. The protoplasts developed into colonies by gradual reduction of sugar concentration. After 45 days of culture, numerous micro-calli formed which were subsequently transferred to a callus formation medium. Plantlets were regenerated by transferring protoplast-derived calli of ca. 2 mm in diameter to a modified Murashige-Skoog medium. Of the 75 calli inoculated, 24 (32%) gave rise to green shoots on a regeneration medium 2 to 3 months after inoculation. These shoots rooted when cultured on a hormone-free medium. These plantlets were successfully acclimatized and grew normally in a greenhouse.
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  • Yasutaka Kano, Hideyuki Goto, Hidenori Fukuda, Kenji Ishimoto
    2001 Volume 70 Issue 4 Pages 438-442
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    The occurrence of bitter cucumber (Cucumis sativus L. cv. Kagafutokyuri) was higher in the bitter line than in the non-bitter line. Total-N, nitrate-N, amino acid-N and protein contents in the leaf were higher in the former, which received twice the nitrogenous fertilizers than the latter. The occurrence of bitter fruit was higher in the application of twice as much nitrogenous fertilizers as usual, and total-N and amino acid-N contents in the leaf were higher in the former case than in the latter. Protein content also tended to be higher in the former than in the latter. Amino acid-N and protein contents tended to be higher in the peel of the bitter fruit than in that of the non-bitter one.
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  • Yasuyoshi Hayata, Kazuhiro Kotani, XinXian Li
    2001 Volume 70 Issue 4 Pages 443-447
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    The effect of the difference between day and night temperatures (DIF), under a 12-hr photoperiod on hypocotyl elongation (HE) of radish (Raphanus sativus L.) and the roles of endogenous indole-3-acetic acid (IAA) and abscisic acid (ABA) on this growth process were investigated. At 10 DIF, HE was rapid enhanced during the day (DP) but slow at night (NP). Hence, the elongation pattern showed a stepped curve. At 0 DIF, HE during DP was only slightly shorter than that during NP so that the slope of the growth curve changed gradually. At -10 DIF, HE was enhanced at NP, whereas it nearly stopped during DP, so that the stepped curve became exaggerated. In all DIF treatments, changes in IAA content paralleled those of HE ; the highest level of IAA was found at 10 DIF at night. Contrarily, a rapid increase and the highest level in ABA occurred after 36 hr after treatment started at -10 DIF during which HE was retarded. These data indicate that DIF regulates HE in radish by controlling endogenous IAA and ABA synthesis.
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  • Ikuo Miyajima, Kayo Miyahara, Kenji Ureshino, Ayano Michishita
    2001 Volume 70 Issue 4 Pages 448-452
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Isozyme variations in six wild evergreen azalea species distributed in Kyushu were investigated and the effectiveness of the isozyme markers for distinguishing them was assessed. Five polymorphic loci in three enzyme systems, Gpi-2, Mdh-1, Mdh-2, Pgm-1 and Pgm-2 were surveyed. Rhododendron sataense had the widest isozyme variation among six azalea species. The allelic variation of R. kaempferi was relatively wide, whereas those of R. kiusianum, R. serpyllifolium, and R. eriocarpum were narrow. Rhododendron eriocarpum, belonging to Tsutsusi series, and R. serpyllifolium, belonging to Serpyllifolia series, were easily distinguished in Gpi-2 from other azalea species belonging to Kaempferia series ; the species belonging to Kaempferia series could not be distinguished from each other in any enzyme systems used in this study. Although we thought that the origin of flower color variation in R. sataense was the result from the natural crossings between R. kaempferi and R. eriocarpum, it appears that R. eriocarpum has little or no role in the flower color variation of R. sataense based on the results of our isozyme analysis.
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  • Yu Akiyama, Naoki Yamauchi
    2001 Volume 70 Issue 4 Pages 453-457
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Chlorophyll (Chl) degrading enzymes in radish (Raphanus sativus L.) cotyledon chloroplasts and their changes in activities with senescence were studied. Most chlorophyllase activity was localized in the chloroplast where little Chl degrading peroxidase activity occurred. Chl oxidase activity was localized both inside and outside the chloroplast. Chlorophyllase activity in chloroplasts increased while the cotyledons senesced ; whereas oxidative enzyme activities, especially those of Chl degrading peroxidase decreased. These findings indicate that chlorophyllase catabolizes Chl a in the chloroplasts ; Chl degrading peroxidase and Chl oxidase, especially the former, are involved in the degradation of Chl a catabolites outside the chloroplasts.
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  • Takashi Haji, Hideaki Yaegaki, Masami Yamaguchi
    2001 Volume 70 Issue 4 Pages 458-459
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    We examined changes in ethylene production and flesh firmness after the harvest of three peach [Prunus persica (L.) Batsch] cultivars : a melting cultivar 'Hakuho', a nonmelting cultivar 'Early Gold' and a stony hard cultivar 'Yumyeong'. The melting and nonmelting cultivars showed increases in ethylene production and drops in flesh firmness, although their degrees differed, whereas the stony hard cultivar produced little or no ethylene and remained firm during storage. Hence, the latter apparently has different ripening characteristics from the former two cultivars. Stony hard is a mutant in ethylene production and, thus, may be used as a genetic source for improving keeping quality of dessert peaches.
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  • Biao Ma, Isao Tarumoto, Qingchang Liu
    2001 Volume 70 Issue 4 Pages 460-462
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    To improve the efficiency of embryo rescue in Lycoris, the components of ovule culture medium, such as sucrose, pH and casein hydrolysate (CH), were studied by using selfed ovules of L. sanguinea as a model explant. A modified MS medium (mMS2) containing macro-salts adopted from Monnier's medium containing 3% sucrose at pH 5.8 was found suitable for ovule culture in Lycoris. The addition of 500 mg·liter-1 CH to mMS2 medium significantly promoted the germination and seedling formation rates and obtaining interspecific hybrids. Consequently, it was utilized in ovule culture for this purpose.
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  • Kanda Whangchai, Hiroshi Gemma, Jumnong Uthaibutra, Shuichi Iwahori
    2001 Volume 70 Issue 4 Pages 463-465
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    The mineral contents of immature and mature mango fruit (cv. Nam Dork Mai), grown under different soil condition, were determined. Fruits, grown under higher Ca/N and (Ca+Mg)/K ratios in soil, remained firm, resisted rot organisms and had longer storage life. The fruit Ca and (Ca+Mg)/K ratio had high positive correlation with storage life, indicating that these parameters are good indicators for storage life. X-ray microanalysis of the distribution of mineral elements in mango fruit revealed that K accumulated mainly in parenchyma cells of the mesocarp, while Ca was lowest in inner mesocarp. Low Ca in fruit could be involved in the occurrence of jelly seed in the inner mesocarp. Thus, fruit quality may well depend upon the condition of the soil.
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  • Katsuhiko Matsuura, Kenji Tanabe, Fumio Tamura, Akihiro Itai
    2001 Volume 70 Issue 4 Pages 466-472
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Leaves at different bearing nodes on current shoots of seven-year-old 'Masui Daufine' fig (Ficus carica L.) trees cultivated in a greenhouse were exposed to 13CO2 during the fruit enlargement and maturation stages at lower nodes. After one week of exposure to 13CO2, the distribution of 13C-photosynthate in fruit-bearing shoot was investigated. The results were as follows : 1. When the 3rd leaf was treated during fruit set and enlargement period at lower nodes, some of the 13C-photosynthates was assimilated by the treated leaf, while a large portion went to the developing young fruit in its axis ; the remainder was partitioned to the adjacent lower stem. Similarly, when 13CO2 was applied to the 6th leaf, much of the 13C-photosynthates remained in the leaf ; the rest was exported to young fruits, inflorescences, leaves, and shoots at the upper and lower nodes. When the 9th leaf was treated, it retained more of the 13C-photosynthates than did the immature fruit in its axis ; a significant amount was retained in the adjacent upper part of the shoot. The 13C accumulation data revealed that the fruit in Stage I had a greater sink strength than had the developing inflorescences. 2. When the fruit on the 5th node was treated with oil one week before harvest (August 3, 1998) to induce early maturity, it showed a highly active sink, importing 13C-photosynthates primarily from leaves on the 3rd to the 7th nodes.
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  • Fumio Fukuda, Naomi Yokoyama, Ryuji Yoshimura, Naohiro Kubota
    2001 Volume 70 Issue 4 Pages 473-480
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    The possible causes of physiological fruit abscission (June drop) in peach (Prunus persica), which occurs between late Stage 2 and early Stage 3, was investigated for two years. The characteristics of fruit development in 'Shimizuhakuto (SH)' which has a high frequency of pit splitting and physiological fruit drop were compared with those in 'Takeihakuho (TH)' and 'Megohime (MH)' which tend to have numerous split pits but low fruit drop and with 'Yamatohakuto (YH)' which manifest a few split pits and a small percentage of fruit drop. SH had a lower percentage of fruit drop than YH but its growth rate during Stage 1 was faster than that of YH. The pits of SH and TH, based on fresh weight and size, grew significantly faster than those of YH throughout the entire developmental period. Seeds of SH elongated faster than those of YH but the former accumulated dry matter slower than did those of the latter after the middle of Stage 2. There was no difference in the dry matter accumulation of the pits between two cultivars. Throughout Stages 2 and 3, the length and cell diameters of embryos were smaller in the fruits of SH than in those of YH. In the former, the sizes of pits and embryos in the split-pit fruits were significantly larger than those in fruits with intact pits. The percentage of dry matter in seeds of split-pit fruits in SH varied widely, but at the heavier end on the distribution, the dry weights were similar in all fruits. Embryo lengths from SH fruits with split-pit was classified into normal and short categories, indicating that some seeds developed normally until pit-splitting stage. Seed weight and the sizes of endosperm and embryo in SH fruit which abscised were significantly smaller compared with those of normal ones, but the weight and size of pits were similar. When fruits of SH trees were thinned to two crop levels, heavy thinning resulted in larger fruits but with a higher percentage of split pits with small embryos and more fruit drop than lightly thinned tree. The high percentage of poorly developed embryos that existed in June drop fruits regardless of thinning level, suggests that inferior seed development prior to pit-splitting is related to June drop in SH.
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  • Akira Ooshiro, Sadao Anma, Takashi Ishida
    2001 Volume 70 Issue 4 Pages 481-488
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    The structure and chemical composition of annual and alternate bearing trees of the Japanese persimmon (Diospyros kaki Thunb.) 'Maekawa Jiro' were studied. Alternate bearing trees (Alternate Group) and annual bearing ones (Control Group) were up-rooted, dissected, and the nutritional status of their parts analyzed. The data were examined with respect to their previous histories and chemical analyses. 1. Alternate Group exhibited large yearly fluctuations in the number of normal flowers (and yield), but their percentage of physiological fruit drop (June drop) was similar to that of the Control Group. The former had smaller fruits with lower Brix values than had those of the latter. 2. The Alternate Group had a smaller percentage of dry matter, particularly in their above-ground parts than had that of the Control Group. 3. The leaf N and P contents of the Alternate Group before and during the bearing years were low as were the P and K contents in 1-yr-old dormant wood. Likewise, the N level in the thick roots and P content in the other vegetative parts were low. 4. The 1-yr-old dormant wood in the Alternate Group had very low starch content in the "On" years, wheras it was consistently high in the Control Group. In both groups, the root starch content was higher than that of the aerial parts. The starch content of all parts of Alternate Group trees following a heavy crop were lower than those of the Control Group. Thus, alternate bearing 'Maekawa Jiro' trees is characterized by excessively high yields in the bearing "On" years, leading to poor nutritional levels and vegetative growth accompanied by low yields in the following "Off" years.
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  • Akira Ooshiro, Sadao Anma, Takashi Ishida
    2001 Volume 70 Issue 4 Pages 489-495
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Differences in structural and nutritional characteristics of Japanese persimmon 'Maekawa Jiro' trees which consistently had low yields (Low Group) and annual bearing ones (Control Group) were assessed. There were up-rooted, dissected, and their structural and nutritional status examined ; the data was then compared with their previous histories. 1. Trees in the Low Group had fewer normal flowers and fruits, a higher percentage of physiological fruit drop, and lighter fruits at harvest compared with the Control Group. 2. While the Low Group was of equal size to the Control Group up to the early years of bearing, the former had larger framework and roots, a reflection of the low yield, than had the latter by end of the experiment. 3. Prior to uprooting, the Low Group had low leaf P while the 1-yr-old dormant wood had low N and P contents. After being up-rooted, the N in the relatively thick roots and P in most parts were found to be low. 4. Analyses of 1-yr-old dormant wood revealed the carbohydrate contents of the Low Group were similar to those of the Control Group. Thus, while the trees sizes of both groups were similar during their early bearing ages, trees of the Low Group which consistently yielded poor crops became larger, initiated fewer flowers, and accumulated less mineral nutrients than did those of the Control Group. Because of the low yield, the roots of the Low Group grew larger and contained more stored carbohydrates than did those of the Control Group in the winter.
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  • Motoyoshi Yamasaki, Hiromi Tsuji
    2001 Volume 70 Issue 4 Pages 496-500
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Garland chrysanthemum (Chrysanthemum coronarium L.) were exposed to 30°C before, during, and after flower bud differentiation to test the effect of the stress on the occurrence of dead heart disorder. 1. Dead heart appeared when the plants at the dome-to late floret-forming stages were placed in an incubator kept at 30°C. No symptoms of dead heart appeared when plants were exposed to the stress during the vegetative or early corolla-forming stages. 2. Application of 0.3% CaCl2 to shoot tips at weekly intervals decreased the occurrence of dead heart and increased plant height, but had no effect on the rate of flower bud development. 3. Plants with dead hearts at the bolting stage in the spring had smaller statures and flower bud diameters, they had shorter stems but more leaves than had healthy plants. The correlation between the number of injured leaves and total number of leaves on the main stem was significant, whereas there were no significant correlations between the number of injured leaves and plant height, stem length, and flower bud diameter. The correlation between the total numbers of leaves and flower bud diameters were significant in both the plants with and without dead hearts. There was a tendency that the more leaves the plants had, the greater probabilities of their exhibiting dead heart. These results indicate that the dead heart occurs when garland chrysanthemum is a reflection of nutritional competition between a large number of leaves and developing flower parts induced by high temperature.
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  • Takahiro Tanigawa, Yasuo Kobayashi, Hiroshi Matsui, Toshihiro Kunitake
    2001 Volume 70 Issue 4 Pages 501-509
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Effects of exposing Eustoma cultivars to high and low growth temperatures for different durations and with an interval of chilling on bolting were examined. In Exp. 1, seedlings of 'Asukanosakura' and 'Asukanoasa' which were grown at 30/25°C (day/night) under a 12-hr photoperiod for 0 to 6 weeks after sowing were exposed to 11°C for 3 weeks and subsequently cultured at 30/25°C, 27.5/17.5°C, and 22.5/12.5°C. All seedlings of both cultivars grown at 22.5/12.5°C bolted ; whereas 13∿88% of those grown at 30/25°C bolted. In Exp. 2, seedling of 'Asukanoyosooi' and 'Miyakomomo', grown at 35/25°C for 0 to 8 weeks under natural photoperiod after sowing, were exposed to 11°C for 5 weeks and then cultured at the above 3 temperature regimes. After the low-temperature treatment, all plants, initially grown for 4 and 6 weeks, bolted after 'Asukanoyosooi' and 'Miyakomomo' attained more than 1.1 and 2.3 nodes per stem, respectively, independent of the final growing temperatures. Contrarily, seedlings that were initially grown for 0 to 2 weeks prior to chilling formed rosettes. In Exp. 3, seedlings of 'Azumanosakura', 'Asukanosakura', and 'Asukanoasa' were grown at 35/25°C for 0 to 2 weeks under a natural photoperiod after sowing, then exposed to 11°C for 1 to 5 weeks, and then cultured at the original day/night temperatures. Most of the seedlings bolted when they were exposed to the chilling temperature for 3 to 5 weeks, regardless of the initial duration of the treatment. In Exp. 4, when seedlings of the 3 cultivars in Exp. 3 were exposed to 35/25°C for 4 to 8 weeks after sowing and subsequently to 11°C for 3 to 6 weeks, all seedlings bolted after 5 weeks of chilling. Thus, we conclude that low-temperature exposure is primarily responsible for the bolting of these Eustoma cultivars which are hard to form rosettes.
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  • Chie Iyo, Sumio Kawano
    2001 Volume 70 Issue 4 Pages 510-515
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Sweetness sorting machines, based on near infrared (NIR) spectroscopy, have been introduced to packinghouses for peaches, apples, oranges, and other fruits for nondestructive quality evaluation. However, the NIR method for Brix values is not always calibrated well, so that a big bias occurs occasionally. In this study, the means of developing a universal calibration for Brix using non-stored apples, which is also suitable for stored samples, was explored. The calibration developed, using NIR spectra [not the multiplicative scatter correction (MSC) one], predicted the Brix values of non-stored samples well but not that of stored ones. With the 5-month stored apples, a bias of 2.66°Brix occurred. However, there was no bias when the spectra of non-stored and stored samples were used to formulate the calibration equation. When calibration and prediction using MSC-treated spectra were performed, the drawback described above could be mitigated. More accurate results were obtained using NIR spectra within 758 to 1161 nm.
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  • Minako Kaneda, Yoshiaki Hara, Takashi Suzuki, Takuo Shiraishi
    2001 Volume 70 Issue 4 Pages 516-518
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Flower buds of sweet cherry (Prunus avium L. cv. Satohnishiki) exposed to critically low temperatures were investigated in relation to browning of pistils, with and without freezing, developmental stage (size) of buds, and their temperatures within buds (bud temperatures). Half of the buds chilled below -1.5°C initiated the freezing process. Thirty to 40 percent of buds freezing at -1.5 to -2.5°C of bud temperatures were injured, resulting in browning of pistils. Even pistils of supercooled buds, browning occurred when the bud temperatures were maintained below -1.5°C for 1 to 2 hours. Hence, pistils were damaged without ice formation when supercooled to subzero temperatures. These supercooled buds were more susceptible to chilling injury during their early stages of development, indicating that some structural and/or physiological changes in developing flower buds are related to the damage.
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  • Toshiki Asao, Kumiko Taniguchi, Kouhei Tomita, Takashi Hosoki
    2001 Volume 70 Issue 4 Pages 519-521
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Species differences to susceptibility to autotoxicity among leaf vegetables grown in hydroponics were studied. Shoot fresh weights of parsley, celery, mitsuba, curled lettuce, head lettuce, edible burdock, garland chrysanthemum, pak-choi and kale cultured in recycled (non-renewed) nutrient solution with and without the addition of activated charcoal to the nutrient solution was compared. Among the species, parsley suffered the most severe growth inhibition in the absence of charcoal, whereas komatsuna, chinese cabbage, radish, takana, welsh onion, perilla and spinach were unaffected. Thus, all species in Umbellifeae, Compositae and some species of Brassicaceae showed autotoxicity.
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  • Hidehiro Nishimura, Shigeaki Atsumi
    2001 Volume 70 Issue 4 Pages 522-524
    Published: July 15, 2001
    Released on J-STAGE: January 31, 2008
    JOURNAL FREE ACCESS
    Two sizes (4-8 and 8-12 mm diam.) of micropropagated bulblets were immersed in 0 (water), 2, 20 and 200 ppm gibberellic acid4 for 2 and 20 hrs or exposed to 5°C for 60 days. Subsequently, the bulblets were grown at 25°C under a 12-hr photoperiod for 60 days. In both sizes, although bulblets immersed in 200 ppm were emerged as chilled and those had more scale leaves than chilled, the leaves were small and the weight of bulblet were not decreased.
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