Journal of the Japanese Society for Horticultural Science
Online ISSN : 1880-358X
Print ISSN : 0013-7626
ISSN-L : 0013-7626
Volume 48 , Issue 3
Showing 1-15 articles out of 15 articles from the selected issue
  • Takashi TOMANA, Naoki UTSUNOMIYA, Ikuo KATAOKA
    1979 Volume 48 Issue 3 Pages 261-266
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    The effect of environmental temperatures on the coloration of Kyoho grapes was investigated by exposing whole vines and clusters separately to different temperature regimes during ripening stage. Young bearing vines were placed in the sunlit growth cabinets kept at 20°C and 30°C and, in each cabinet, their clusters were enclosed in acrylic cylinders whose inside temperature was regulated at 15°, 20°, 25° and 30°C, respectively. In another experiment only night temperatures around clusters of young bearing vines grown under natural conditions were regulated at 15°, 20°C and 25°, 30°C in the same manner.
    Anthocyanin contents in the berries increased with lowering in temperature around clusters from 30°C to 15°C regardless of temperature in the cabinets. Low night temperature around clusters, also, increased anthocyanin levels compared to high night temperature. Sugar levels in the skin were not affected by temperature around clusters. However, ABA contents in the skin of grapes exposed to low temperatures were much greater than those of grapes exposed to high temperatures.
    These results indicate that fruit temperature acts an important role on anthocyanin synthesis of Kvoho grapes, and that ABA levels in the skin may be involved in the coloration affected by the fruit temperatures.
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  • Takanori YAMAMOTO, Shunzo WATANABE, Hisashi HARADA
    1979 Volume 48 Issue 3 Pages 267-278
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    Slowdown in closing action of stomata is a main factor in the occurrence of leaf burn in pear trees. The purpose of the present study is to observe the nature of this slowdown and to clarify its cause. The results obtained are summarized as follows:
    1. The stomata of the leaves on the shoot cuttings from various deciduous fruit trees were tested for their photoactive reaction. Stomatal movements were not so sensitive in young leaves, but became most sensitive when the leaves reached fullsize, and thereafter became less sensitive again. The leaf diffusion resistance in light (RL) rose gradually and in the dark (RD) fell gradually with time after full expansion of the leaves. Among fruit trees sampled, this tendency was especially evident in pear trees. Among pear cultivars, this slowdown in closing and opening action was most evident in Bartlett (highly susceptible to leaf burn), somewhat evident in Grand Champion (susceptible) and less evident in Red Bartlett (resistant).
    2. From the results of the hydroactive reaction of stomata of leaf disks sampled in late August, it was clear that for almost all the fruit trees, the thresholds of water potentials (ψ) of their leaves to stomatal closure were the lowest in basal leaves and the highest in terminal leaves. The thresholds of almost all the trees were around -20 bars, although those of the basal leaves of both Bartlett and Grand Champion were below about -50 bars.
    3. It was found that the slowdown in closing action of stomata within a single leaf was not uniform. For example; the larger the stomata of basal leaves of Bartlett, the wider the aperture of stomata in the dark. Therefore, this open-type stomata prevented the leaf diffusion resistance from rising at a higher level. However, this tendency was not found in the terminal leaves of Bartlett or in any of the leaves of Red Bartlett.
    4. The hysteresis of RL against ψ of the intact leaves of Bartlett was flatter than that of Red Bartlett. The levels of both RL and ψ of Bartlett leaves were lower than those of Red Bartlett in the hysteretic process.
    5. Foliar sprays of salts of potassium, chlorine and calcium did not affect the slowdown in closing action of stomata of leaves on shoot cuttings of Bartlett. ABA application at high concentrations induced the stomatal closure both in the light and the dark. However, ABA application at low concentrations accelerated the stomatal closures in the dark only.
    6. Several metabolic inhibitors prevented the stomata of terminal leaves of Bartlett and of basal leaves of Red Bartlett from closing in the dark.
    7. The migration of potassium ions in the stomatal complex was evident during stomatal movement of epidermal strips of pear leaves in middle June. However, the remains of potassium ions were found in the guard cells in the dark in late August, especially in the large stomata of basal leaves of Bartlett. Histochemical observations indicated that such stomata had less enzyme activities in reducing TTC, or oxidizing cytochrome C than the smaller ones.
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  • Fusao MIZUTANI, Hiroyuki ITAMURA, Akira SUGIURA, Takashi TOMANA
    1979 Volume 48 Issue 3 Pages 279-287
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    To examine whether there exist growth inhibitors other than the hydrolysates of cyanogenic glucosides, which have been known to be responsible for the peach replant problem, extracts of peach roots, leaves and orchard soils and leaf leachates from peach trees were separated by column chromatography.
    Condensed tannins were detected in the main inhibiting fractions of peach root extracts. They yield a red bright color by drastic heating in 2 N HCl. The behavior of the growth inhibiting fractions always coincided with that of the fractions containing the condensed tannins in different kinds of column chromatography and partition systems. More condensed tannins were excreted from peach roots under anaerobic than aerobic conditions. One of these compounds was purified and tested for root growth of peach seedlings on agar media. It greatly reduced the root growth at 5×102 and 1×103ppm. These findings are discussed in relation to the peach replant problem.
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  • Gen-ichi HIRAI, Masaru HORI
    1979 Volume 48 Issue 3 Pages 288-294
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    1. Studies were carried out to know whether the area of profitable cultivation of satsuma mandarin could be determined by the plants belonging to specific species, or certain groups of species in the natural vegetation, using same as indicator plants.
    2. Among shrine forests in the valleys of lower Arida and Kino river, those of climax forest type were selected, and classified into 5 types in view of the distribution pattern of certain species of plants. In relation to the groups of plants and the dominance in each type, changes in cultivation areas of satsuma mandarin were examined.
    3. As a result the area where the group of plants belonging to Elaeocarpus sylvestris, Rapanaea neriifolia, Symplocos glauca, Daphniphyllum teijsmannii grow naturally, was considered to be suitable for satsuma mandarin cultivation judging from fruit quality.
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  • Nobuo SUGIYAMA, Masatoshi IWATA
    1979 Volume 48 Issue 3 Pages 295-300
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    In order to clarify the difference in the relationships between the soil exchangeable K and the growth responses of seedlings to K fertilizer under different growing seasons, 6 kinds of vegetables were grown with 2 levels of K application (0g and 1g K2SO4 per pot) on the 4 soils containing different exchangeable K, in summer and in winter, respectively. All pots received 1g ammonium sulfate and 5g superphosphate. In the experiments of spinach and lettuce 3g slaked lime was applied to all pots. Germinated seeds were sown in 1/5, 000-are Wagner pots filled with 1.6kg soil (oven dry basis). Seedlings were harvested at the time when the first true leaf began to emerge.
    1. In both seasons, increases in the fresh weight of spinach and turnip seedlings due to K application were obtained on the soils containing 75ppm and 161ppm exchangeable K, but not obtained on the soils containing 254ppm and 343ppm exchangeable K.
    2. In both seasons, increases in the fresh weight of lettuce and radish seedlings due to K application were obtained only on the soil containing 75ppm exchangeable K, but not obtained on the soils containing 254ppm and 343ppm exchangeable K. On the soil containing 161ppm exchangeable K, K application increased the fresh weight of seedlings only in winter.
    3. Increases in the fresh weight of cucumber and carrot seedlings due to K application were not obtained on the soils containing 161ppm, 254ppm and 343ppm exchangeable K in both seasons. Although cucumber seedlings increased their fresh weight with K application on the soil containing 75ppm exchangeable K in both seasons, carrot seedlings increased only in winter.
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  • Nobuo SUGIYAMA, Masatoshi IWATA
    1979 Volume 48 Issue 3 Pages 301-308
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    Experiments were carried out to ascertain the relationship between the soil exchangeable K and the growth responses of radish to K fertilizer, and factors affecting this relationship at the seedling stage, comparing with those at the harvest stage reported previously(8). Seedlings were grown under combinations of 2 levels of K with 2 levels of other factors, on the 4 soils containing 75ppm, 161ppm, 254ppm and 343ppm exchangeable K, respectively. The levels of K were 0g and lg K2SO4 per pot and the levels of other factors were shown in Table 2. Five germinated seeds were sown in 1/5, 000-are Wagner pots filled with 1.6kg soil (oven dry basis). Seedlings were harvested at the time when the first true leaf began to emerge. All pots received 1g ammonium sulfate and 5g superphosphate except in the N or P experiment.
    1. On the soil containing 75ppm exchangeable K, K application increased the fresh weight of seedlings regardless of levels of factors combined with K.
    2. On the soil containing 254ppm or 343ppm exchangeable K, K application did not increase the fresh weight of seedlings in all experiments.
    3. On the soil containing 161ppm exchangeable K, increases in the fresh weight of seedlings due to K application were obtained in the experiments of Mg and of the soil water regimes, but not obtained in the experiments of P, lime, Na and the light intensity, regardless of levels of these factors. In the N experiment, increases in the fresh weight of seedlings due to K application were obtained with the addition of 3g ammonium sulfate, but not with 1g. (Table 10).
    4. The above-mentioned results were in accordance with those of the previous experiments(8). However, the level of the exchangeable K content of the soil, on which growth responses due to K application were variable, was slightly higher at the harvest stage (ca. 240ppm) than at the seedling stage (ca. 160ppm).
    5. In case increases in the fresh weight of seedlings due to K application were obtained on the soil containing 161ppm exchangeable K, K concentration (dry weight basis) of tops was below 3.5% except in the Na experiment.
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  • Hisajiro YUKINAGA, Masaru OGATA, Masao HIRABAYASHI, Tetsuya TAKAHASHI, ...
    1979 Volume 48 Issue 3 Pages 309-321
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    1) Parthenocarpy of dwarf tomato (cv. Miniature) induced by synthetic naphthoquinone derivatives was investigated. 3-Phenyl-4, 9-dihydronaphth [2, 3-d] isoxazole-4, 9-dione, 2-benzimidoyl-3-hydroxy-1, 4-naphthoquinone, 2-(3--methoxyben-zimidoyl)-3-hydroxy-1, 4-naphthoquinone, 2-(3-pyridylcarbimidoyl)-4 hydroxy-1, 4-naphthoquinone, 2-(4-chlorobenzimidoyl)-3-hydroxy-6, 7-dimethyl-1, 4-naphthoquinone, 6-(or 7-) benzimidoyl-7 (or 6-)-hydroxy-5, 8-dihydroquinoline-5, 8-dione, 2 (N-methylbenzimidoyl)-3-hydroxy-1, 4-naphthoquinone, 2-benzoyl-3-hydroxy-1, 4-naphthoquinoe, 3, 5'-diphenyl-4-oxo-4, 9-dihydronaphth [2, 3-d] isoxazole-9-spiro-', 3', 4'-dioxazole) and 3, 5'-diphenyl-4, 5-dihydro-naphth [2, 1-d] isoxazole-5-spiro-2', 1', 3', 4'-dioxazol-4-one induced clearly parthenocarpic fruits. These compounds are of a new type of plant growth regulators and their chemical structures are different from those already known.
    2) One of these compounds, 2-benzimidoyl-3-hydroxy-1, 4-naphthoquinone (bendroquinone) was applied to emusculated tomato (cv. Fukuju Ni-Go) flowers. The parthenocarpic fruits showed the same development of fruit as by application of synthetic auxins, HCPA and 4CPA.
    3) The ovule development of the parthenocarpic fruits was histologically observed. The development of the endothelial cells induced by bendroquinone was not so active as that by HCPA for a period of two weeks after anthesis, but one week later, there was no difference in the development of the pseudoembryo between applications of the two chemicals.
    4) Bendroquinone isn′t easily soluble in water. It was formulated as 9% wettable powder and applied to tomato (cv. Beiju) flowers in a plastic green house as the setting agent. The fruit set percent and the yield of the first cluster were not so high as compared with the application of HCPA and 4CPA, but in case of the second, the third and the fourth clusters, they were higher. The fruit set percent and the total yield per plant by the application of 200ppm and 300ppm bendroquinone, 200ppm HCPA and 30ppm 4CPA were respectively 73.8% 15.92kg, 78.8% 15.66kg, 73.9% 16.03kg and 60.2% 13.34kg. The puffiness extent of the fruits was slight and there was no phytotoxicity on the plant.
    5) For induction of parthenocarpy by bendroquinone, the application at earlier stages of flower development was effective as compared with HCPA and 4CPA. The induction of parthenocarpy related closely to the volume and the time retained on the calyx. Therefore, addition of the spray adjuvant would be good for the induction.
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  • Akira ISHIDA, Masao MASUI, Akira NUKAYA, Takayasu OGURA
    1979 Volume 48 Issue 3 Pages 322-326
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    Experiments were conducted to determine the effect of diluted sea water on the growth and flowering of the‘Coral’carnation cultivar. Nine young plants were planted in a wooden container (40×40×12cm) filled with sand or soil. Sea water diluted with Hoagland′s solution, and also tap water was used for both sand and soil cultures. Each solution contained 0, 100, 250, 500, 1, 000, 2, 000 and 3, 000ppm Cl. Treatments were continued from April 10 to flowering. Salt injury was not found at 0 and 100ppm Cl. Plant height and top fresh weight of the flowering plant grown in sand and soil decreased above 250ppm Cl of sea water, and flowering was delayed above 500ppm Cl. The degree of injury was intensified as sea water was raised from 250 to 3, 000ppm Cl. Dieback on the leaves appeared above 500ppm Cl in sand culture and above 1, 000ppm Cl in soil culture about 45 days after the beginning of treatment. Generally the injury was more severe in sand than in soil cultures, and was highly correlated with Mg and Na in the leaves, and with Cl in the leaves, stems and petals. With increasing sea water concentrations, the total N, P and K in the leaves decreased, and the Cl, exchangeable Mg and Na, and EC values of the sand and soil increased.
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  • Masayoshi FUJITA
    1979 Volume 48 Issue 3 Pages 327-335
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    Effects of low temperatures on flower bud initiation and blooming of common stock plants were studied. Low temperature treatments were conducted at early stages of plant growth. The results obtained are summarized as follows.
    1. When common stock plants were grown within low temperature regimes with a daily minimum temperature of 0°C during the period from the 5th day after seed planting to blooming, the number of nodes to inflorescence was fewer in early flowering cultivars than in late flowering cultivars of branching stocks. In nonbranching common stocks, however, there was only a little difference in number of nodes to inflorescence among extremely early, early, and medium flowering cultivars, thus the node number of a late flowering cultivar‘Awanoharu’was the largest among the cultivars examined. Concerning the cultivars examined, it can be concluded that the fewer the number of nodes to inflorescence, the smaller the number of days from seed planting to the flower-budding.
    2. Common stock plants, which had previously been grown at temperatures higher than 18°C from seed planting to each of the cotyledon-, 2-, 4-, 6-, 8-, and 10-unfolded-leaf stages, were transferred to low temperature regimes with either a daily minimum temperature of 1°C or 4°C. In most cultivars of the branching and non-branching common stocks, except the extremely early cultivar, it was observed that the earlier the beginning of low temperature treatment, the fewer the number of nodes to inflorescence.
    3. Common stock plants, which had previously been grown at temperatures higher than 18°C from seed planting to the 10-unfolded leaf stage, were transferred to low temperature regimes with a daily minimum temperature of 4°C for 0, 10, 20, 30, and 40 days, and then transferred further to high temparature regimes with a daily minimum temperature of 18°C. The shortest duration of low temperatures necessary for 100% blooming was 10 days in medium flowering cultivars of branching stocks and in early and medium flowering cultivars of non-branching stocks, 20 days in late flowering cultivars of branching stocks, and 40 days in late flowering cultivars of non-branching stocks.
    In every cultivar, high percentages of blooming occurred only in cases where flower buds thoroughly differentiated before the end of the low temperature treatment.
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  • Takeshi HOSOYA, Kazuo KITAMURA, Tadashi ISHIGAMI
    1979 Volume 48 Issue 3 Pages 336-344
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    The present experiment was set up in factorial design to determine the effects of soil types combined with differential supplies of three major nutrient elements on the growth and flowering of potted chrysanthemums. The fertilizer treatments consisted of three levels of nitrogen fertilization, i. e., 100, 250, and 400ppm, which was applied as urea solution, and potash, i. e., 200, 400, and 600ppm, which was applied as potassium sulfate solution, in the presence of 1 or 3g/pot of phosphorus applied as mixed phosphates (1 fused phosphate : 1 double superphosphate). Each of these treatments was combined further with two types of soils, i. e., alluvial and volcanic ash soils. The results obtained are as follows :
    1) Potted chrysanthemums grown on alluvial soil markedly exceeded those grown on volcanic ash soil in such attributes as size and weight of single leaves, leaf number per lateral shoot, and weight of inflorescences per stock.
    2) High rate of nitrogen (400ppm) applied at early stages of plant development tended to suppress vegetative growth though during anthesis it produced rather increased amounts of leaves and inflorescences per stock. High rate of nitrogen application also promoted the flowering of potted chrysanthemums. Application of increased phosphorus resulted in an increased amount of plant growth. The high rate of potassium applied at early stages of development exerted some inhibitory effects on plant growth, whereas during anthesis potassium applied at the rate of 400ppm caused a maximum growth. These results indicate that regarding nitrogen and potassium rather low rates of fertilization at early stages, followed by high rates at middle and later stages of development, are recommended for potted chrysanthemum culture.
    3) Effects of differential supplies of three fertilizer elements on plant growth depended closely upon the soil type used. That is, on the alluvial soil the inhibitory effects of early, high-rate nitrogen application were noticeably alleviated and its later, high-rate application produced more stimulated plant growth as compared to that produced on the volcanic ash soil. Increased phosphorus affected the plant growth more favorably on volcanic ash soil than on alluvial soil, whereas effects of increased potassium on growth were more marked on the latter than on the former soil. High rates of phosphorus fertilization virtually overcame the delay of flowering that was caused by the adverse effect of volcanic ash soil.
    4) Every major nutrient element affected the growth of potted chrysanthemums synergistically with other elements, though a maximum interaction was effected in the combination of nitrogen with phosphorus.
    5) It is concluded that properly balanced fertility should be maintained for every distinctive stage of plant development along with the soil type employed.
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  • Syoichi ICHIHASHI
    1979 Volume 48 Issue 3 Pages 345-352
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    1. The characteristics of seven culture media devised for the growth ofBletilla striata seedlings were tested and confirmed as originally intended. Shoot growth was promoted on the medium having the composition of NH4+: K+:Ca++:Mg++=50:30:10:10, NO3-:H2PO4-: SO4--=50:30:20%, and an ionic concentration of 60meq/l=∑Cn+=∑An-. Root growth was resumed without retardation of shoot on the medium having the composition of NH4+: K+: Ca++: Mg++=40: 30: 20: 10, NO3-: H2PO4-: SO4--=60: 30 : 10%, and an ionic concentration of 40meq/l=∑Cn+=∑An-. The root growth was excellent on the medium having the composition of NH4+: K+: Ca++: Mg++=20: 60: 10: 10, NO3-: H2PO4-: SO4--=50: 30: 20%, and an ionic concentration of 20 meq/l=∑Cn+=∑An-. In addition, the shoot growth was improved without retardation of root growth on the medium having the composition of NH4+: K+: Ca++: Mg++=20: 40: 30: 10, NO3-: H2PO4-: SO4-=60: 30: 10%, and an ionic concentration of 17meq/l=∑Cn+1 and 23 meq/l=∑An-. Both shoots and roots had reached their full growth at relatively low concentrations of total ions and/or of ammonium ions in the culture medium.
    2. The effects of different media on the orchid growth were investigated with Bletilla striata, Dendrobium nobile, Laelia anceps, Cymbidium Sensation ′Purple Queen′×C.OrionC. pumilum var, album, Paphiopedilum insigne var. sanderae, and Dortaenopsis hybrid. Culture media used were Knudson′s, modified Vacin & Went′s, Kano′s, Thompson′s, and Media 7 and 8 devised forBletilla striata.
    Bletilla striata showed satisfactory growth on all the media except Knudson′s. However, the top to root ratio differed on different media. Seedlings on a modified Vacin & Went′s medium and Medium 7 showed a normal growth of both shoot and root. On the other hand, seedlings on Thompson′s medium showed favorable shoot growth, whereas those on Kano′s medium showed favorable root growth.
    Although seedlings of D. nobile and L. anceps grew normally and uniformly on Kano′s medium, many of the seedlings on the other media grew abnormally and produced callus-like tissues. Although fresh weight was great on Thompson′s medium, germination was inhibited on this medium.
    Seedlings of Cymbidium showed a growth behavior somewhat different from that of D. nobile and L. anceps. The germination of seeds on Thompson′s medium was not inhibited. But the growth of seedlings was rather stimulated. Seedling growth of both C. Sensation×C.Orion and C. pumilum was slow on Knudson′s medium and that of C. pumilum was strikingly retarded on Media 7 and 8.
    The growth of Paphiopedilum seedlings was poor on ail media. However, seedling growth on a modified Vacin & Went′s medium was slightly promoted. The growth of Dortaenopsis seedlings on Thompson′s medium was superior to that on the other media, while their growth was poor on Kano′s medium and Medium 8.
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  • Hiroshi HYODO, Yoshinori HASEGAWA, Yoshiaki IBA, Masafumi MANAGO
    1979 Volume 48 Issue 3 Pages 353-358
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    CO2 evolution by Satsuma mandarin (Citrus unshiu Marc.) fruit and CO2 concentration inside the fruit were greatly enhanced by dropping 46cm 10 times on the board. The rise was so rapid that there was almost no lag. The enhanced rate of CO2 evolution by the dropped fruit and the increased CO2 concentration in the fruit declined in a short time so that the increment was reduced to half in 5hr and 3hr for the former and latter, respectively. The enhanced rate of CO2 evolution was not reduced to the basal level, possibly because of the increased rate of CO2 production by the peel tissue. O2 uptake by fruit was also promoted.
    Ethylene production was not stimulated by dropping. The concentration of acetaldehyde was not increased either in the atmosphere in the fruit in a short period after dropping. A volatile compound that has not been identified yet rapidly appeared in the fruit by dropping, but it returned very sharply to the basal low level within 20min. It is not likely that these substances may function in enhancing respiration caused by the dropping impact.
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  • Shigeyoshi YAMASHITA, Toshihiro WADA, Yoshinobu KITANO, Shigeyoshi HAT ...
    1979 Volume 48 Issue 3 Pages 359-366
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    In order to devise effective measures for preventing satsuma mandarin fruits from mechanical injury, allowable external forces exerted upon the fruit were determined under different dropping conditions, judging from the incidence of juice sac breakage produced at every step of the fruit-packing line and in other handling processes.
    1. Impact forces larger than 10kg that were involved in fruit collisions with the floor and walls of the packing equipment markedly caused the breakage of juice sacs in M-sized satsuma mandarin fruits.
    2. When test fruits were dropped on a hard board from initial positions higher than 40cm, breakdown of juice sacs occurred by only one dropping. Similar injuries of juice sacs were produced by three-repeated droppings from a height of 30cm. However, droppings of more than ten times were necessary when dropped from heights less than 20cm. The impulsive force that was produced in the fruit dropped from a height of 30cm was about 10kg.
    When test fruits were dropped on layers of other satsuma mandarin fruits, the incidence of juice sac breakage in the dropped fruit was rather slight as compared to that of fruits included in the layers. The extent and frequency of the occurrence of juice sac breakage were sharply increased when initial positions of dropping became higher than 30cm. This fact indicates that the maximum allowable dropping height of M-sized satsuma mandarin fruits for preventing mechanical injury is about 30cm.
    3. Buffering effects of soft urethane mats, which are expected to reduce the impact force and consequently alleviate the incidence of juice sac breakage, were investigated. Soft urethane mats thick enough to reduce impact forces below the allowable external force (10kg) could thoroughly prevent dropped fruits from breakdown of juice sacs. With initial heights less than 70cm, soft urethane mats 20 to 30mm thick were most effective for reducing the impact forces produced upon impact. Urethane mats thicker than 50mm, however, exerted larger impact forces on dropped fruits than mats with 20 to 30mm thickness, resulting in severer breakdown of juice sacs.
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  • Shigeyoshi YAMASHITA, Jumpei MORIMOTO, Hiromu UDA
    1979 Volume 48 Issue 3 Pages 367-373
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    Both static loads and stack height allowable for the stacking of satsuma mandarin fruit were determined from the results of juice sac breaking produced in stacked fruits.
    1. Juice sac breaking produced under static loads was compared among various-sized fruits of early satsuma mandarin as well as between early and late satsuma cultivars. Fruits of early satsuma were broken more readily than those of late satsuma. Fruits coincident with or smaller than L-size were broken more readily than those which were coincident with or larger than 2L-size.
    2. Effects of the application of static loads and loading duration on the breaking of juice sacs were investigated with M-sized fruits. Breaking of juice sacs did not occur within 60hr under 0.5kg static load and within 120hr by 0.3kg loading, whereas under static loads greater than 1kg the juice sac was broken within 1min When static loads were exerted on stacked fruits for a long period of time, the allowable load seemed not to exceed 0.5kg to a fruit.
    3. Allowable stack height of M-sized fruits, which was calculated from the experimental data, was about 35cm when static load of 0.5kg to a fruit was exerted on the bottom layer of fruit stacks. In other tests, stack height of 33cm seemed allowable for 10-day stacking of fruits without breaking of juice sacs.
    4. Allowable stack height calculated seemed to coincide fairly well with the allowable height determined from the experimental results, which seemed applicable to the stacking of satsuma mandarin fruit practised in packing and storage houses.
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  • Masaaki TSUKAMOTO
    1979 Volume 48 Issue 3 Pages 374-380
    Published: 1979
    Released: July 05, 2007
    JOURNALS FREE ACCESS
    Effects of size, maturity, and impact position of fruit on the severity of mechanical injury of peaches were studied. The results obtained are summarized as follows:
    1. In both impact and compression treatments, the severity of injuries was closely correlated with fruit maturity. With respect to impulsive collisions, the flesh firmness allowable for resisting mechanical injuries could be determined. When ‘Sunago-wase’peach fruits were dropped onto a hard board 2.7cm thick from a height of 20cm, the allowable flesh firmness was about 21b. by the Magness-Taylor pressure tester.
    2. Even in mature fruit, fleshy tissues subjacent immediately to the skin were not injured by conventional handling. In the overripe fruit, however, such subjacent tissues became very sensitive to bruising. Most lesions belonged to the shape pattern of either ‘ship′s bottom’or‘inverted triangle’.
    3. No correlations were observed between fruit weight and severity of bruising, although small fruits (32 fruits to a packing frame) seemed relatively sensitive to compressive loads.
    4. Bruises occurred most frequently at the stem end of fruit. However, there were no significant differences in flesh firmness among different locations on the fruit.
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