Journal of the Japanese Society for Horticultural Science
Online ISSN : 1880-358X
Print ISSN : 0013-7626
ISSN-L : 0013-7626
Volume 46 , Issue 4
Showing 1-16 articles out of 16 articles from the selected issue
    1978 Volume 46 Issue 4 Pages 435-441
    Published: 1978
    Released: July 05, 2007
    A tentative discrimination on various citrus cultivars was carried out in order to ascertain the applicability of discriminant function method to clustering of promising and useless seedlings at an early stage of citrus hybrid selection.
    Volatile constituents, shape of the leaf blade, aspects of the apex and fringe of leaves, and the presence or absence of leaf wings were adopted as qualitative repressors of the discriminant function. Volatile compounds were analyzed by gas chromatography. Chromatograms obtained, then, were classified in several patterns based on the absorption peaks and their height. Morphological characteristics were categorized according to the criteria presented by the Fruit Tree Research Station (MINIST. AGRI. FOREST., Okitsu Branch). On the other hand, dummy regressand variables were categorized as follows: 1) Cephalocitrus, 2) Aurantium, 3) Osmocitrus, 4) Acrumen, and 5) the Papeda group including Limonellus and Citrophorum. Parameters of the discriminant function were estimated by the quantification method developed by Hayashi.
    The highest value of the correlation ratio which is an indicator of discrimination efficiency was 0.862 corresponding to the first root (eigenvalue of characteristic equation), and 0.809 corresponding to the second root.
    Sample scores obtained from the first eigenvector corresponding to the first root were plotted on the x axis while those from the second eigenvector corresponding to the second root were plotted on the y axis. On the x axis, the cluster of the points of Cephalocitrus lies between 1.2 and 2.6, that of Osmocitrus between -1.3 and -1.5, that of Acrumen between 0. and -0.6, and that of the Papeda group between 0.7 and 1.2. In the two-dimensional distribution of the points which are referred to as the coordinates (xs' and ys') corresponding to the first and second sample scores, respectively, the clusters of the points of Osmocitrus, Acrumen, and Aurantium fall into the second quadrant while those of Cephalocitrus and the Papeda group fall into the fourth quadrant.
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  • Takao ICHII, Kenichi HAMADA
    1978 Volume 46 Issue 4 Pages 442-448
    Published: 1978
    Released: July 05, 2007
    A rind disorder (rind yellow spot) of Naruto (Citrus medioglobosa Hort. ex TANAKA) which was recently found in Awaji island was studied. The disorder occurs between late January and late March. The first visible sign is characterized by a small, yellowing area on the rind surface near the stylar end of the fruit. In the severe cases, it spreads to a large area of the fruit surface, sometimes followed by browning or decay. Tissue abnormalities were found immediately below the yellowish discolored surface area, which could be easily stained with the phloroglucinol-HCl. Good colored fruits from the outside positions on the tree were much more susceptible than less colored fruits from the inside positions on the tree. GA treatment reduced the incidence of the disorder, while ethephon treatment increased it. High P and K, and low Ca and Mg were associated with the rind of fruits from the inside positions on the tree as compared with that of fruits from the outside positions on the tree. GA treatment slightly decreased Ca and Mg concentrations in the fruit rind.
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  • Shigetoshi KAWAMATA
    1978 Volume 46 Issue 4 Pages 449-456
    Published: 1978
    Released: July 05, 2007
    The relationship between the levels of nutrients and the various degrees of the disordered fruit of Nijisseiki pear, were studied by chemical analysis of the fruits. The results obtained are as follows:
    1) Phosphorus content increased while total nitrogen and calcium contents tended to decrease as the disease progressed. It seemed that this physiological disorder became apparent when calcium content fell to a level of 0.047% or less, based on dry weight.
    2) The amounts of total sugars, reducing sugars and fructose in affected fruits were lower while the amounts of glucose and starch were higher than those in normal fruits. In particular, fructose content showed a remarkable change proportionally with the degrees of disorder, but glucose content increased only slightly.
    3) A significant positive correlation was observed between total nitrogen content, and total sugars, and reducing sugars or fructose contents, between calcium content, and total sugars or fructose contents, whereas a significant negative correlation was found between total nitrogen content, and glucose or starch contents, between calcium and starch contents. No correlation was found between calcium and glucose contents.
    4) From the results of principal component analysis and multiple regression analysis, it is concluded that the degree of ‘yuzuhada’ disorder is characterized by a decrease in calcium absorption accompanied by changes in sugar composition in affected fruit. In particular, fructose content is remarkably lower for affected fruits than for normal ones.
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  • Shuji KUBOTA, Shoichiro AKAO, Michito HAYASHIDA
    1978 Volume 46 Issue 4 Pages 457-464
    Published: 1978
    Released: July 05, 2007
    1. Twenty four hours after 14CO2 feeding to the leaves, malic acid had the highest level of total and specific radioactivity among the organic acids extracted from the juice vesicles, and citric acid had the second highest total activity. An unidentified acid compound had a relatively high activity.
    2. Pyruvic acid-2-14C was fed as a substrate for acid formation to the one young fruit on a shoot, and NaH14CO3 was fed as a source of carbon-dioxide to the other young fruit through the pedicel. After three hours of pyruvic acid feeding, malic acid, citric acid and aspartic acid were the major labelled compounds in the vesicles. Then, a marked increase and redistribution of activity in acids took place with time, and the levels of total and specific activity in citric acid increased steadily. The sorts of labelled compounds into which activity was incorporated from NaH14CO3 were essentially similar to those in pyruvic acid-2-14C feeding.
    3. These results seem to support the theory that the dark fixation of carbondioxide plays an important role in the synthesis of the organic acids in citrus fruit vesicles.
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  • Tatsuo SHIMIZU, Hirotaka TORIKATA, Shizuo TORII
    1978 Volume 46 Issue 4 Pages 465-478
    Published: 1978
    Released: July 05, 2007
    Using the bearing and non-bearing trees of the 3-year-old ‘Miyagawa-wase’ with which the annual net production (ΔPn) and gross production (ΔPg) were previously determined, seasonal changes of carbohydrate contents (percent of dry weight) in their various organs were studied.
    During the growing season from July to September, sugar content in the main organs of both types of trees decreased to the lowest level. Then, it increased and reached to the highest level in January, but decreased again thereafter. Starch content in the main organs, especially old leaves and underground parts, of both types of trees decreased from April until July. After this period, although starch content became constant in both types of trees, that in the non-bearing trees was always higher than that in the bearing trees. After January it increased in both types of trees. In contrast, the content of acid hydrolizable polysaccharide in the main organs of both types of trees showed an increase to the highest level from July to September. Then, it decreased until January. After January, it began to increase again in both types of trees. No differences in the content between the bearing and the non-bearing trees in each period were observed.
    Functional carbohydrate content, which is the sum of total sugar content, starch and acid hydrolizable polysaccharide, increased rapidly in the main organs of the non-bearing trees after thinning fruits, while that of the bearing trees increased rapidly after harvesting fruits.
    Seasonal fluctuations of this carbohydrate content were divided into three phases:
    In the first phase from April 5 (sprouting stage) to May 31 (arresting stage of current shoot elongation), new organs developed slowly depending partially on the conversion of carbohydrate reserved in the old organs. In other words, three percent of the total dry matter supplied in this phase was from carbohydrate reserved in such organs.
    In the second phase from June 1 to January 11 (resting stage of the tree growth), production of dry matter was extremely great, and used mostly for growth and respiration, but saved very little for reserved carbohydrate, that is, the amount of accumulated carbohydrate was approximately 16% of ΔPg in the bearing trees and 10% in the non-bearing trees.
    In the third phase from January 12 to February 25 (resting period of the tree growth), no growth occurred in both types of trees, but the reserved carbohydrate began to be consumed again.
    Annual accumulation of reserved carbohydrate in each individual bearing tree was approximately 38g (12% of annual ΔPg), 9% of which was distributed to the leaves, 10% to the stems, 6% to the trunk, 18% to the underground parts, and 58% to the fruits. In contrast, annual accumulation of reserved carbohydrate in each individual non-bearing tree was approximately 28g (8% of annual ΔPq), 11% of which was distributed to the leaves, 22% to the stems, 11% to the trunk, 47% to the underground parts, and 9% to the fruits before thinning.
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  • Sachiko MATSUBARA, Haruyoshi HIHARA
    1978 Volume 46 Issue 4 Pages 479-486
    Published: 1978
    Released: July 05, 2007
    Onion bulblet formation on receptacles in vivo and in vitro was studied histologically.
    Onion bulblet formation in vivo was induced by clipping immature florets and pedicels and spraying 10mg/l N6-benzyladenine (BA) or water daily for two weeks. BA spray produced larger bulblets than water spray.
    Histologically, adventitious buds had been initiated from pedicel bases and receptacles at the termination of treatment. Then, they developed scaly leaves successively, and 5 weeks later bulblets were completed, and fell down from receptacles. These bulblets seemed to be in a state of relative rest.
    For in vitro culture, receptacles were cut in 2 or 4 pieces and cultured on the modified Murashige and Skoog′s medium (the basal medium) with or without α-naphthaleneacetic acid (NAA) and BA. The addition of NAA and BA increased the number of plantlets regenerated. Plantlets were produced on younger receptacles as a result of development of the primordia of floral organs into leaves, while on older receptacles, from which florets were removed at the explanting time, as a result of initiation of adventitious buds on them. Leaf sheathes in all plantlets swelled and formed bulb scales 30 to 90 days after explanting. Plantlets regenerated from receptacles of younger stages needed a longer period for bulbing. Callus formation was induced when florets were planted, and then plantlets were initiated from callus.
    The number of plantlets regenerated per receptacle was different according to the varied concentrations of NAA and BA incorporated into the medium. At 1mg/l NAA, higher concentrations of BA increased the number of plantlets. At 10mg/l NAA, however, the number of plantlets did not differ with the concentrations of BA.
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    1978 Volume 46 Issue 4 Pages 487-494
    Published: 1978
    Released: July 05, 2007
    Our reseach on the single truss tomato culture was begun in an attempt to find out some means to increase the efficiency of tomato production. The results are summarized as follows
    1. Seeds of tomato cultivars FTVNR-3 and Dantobi-Yozu (self-topping variety) were sown nine times monthly on the 10th of each month from July 1974 to March 1975.
    The planting density was approximately 11, 000 plants per 10 a and the plants were all pinched at three leaves above the first inflorescence.
    2. Days from sowing to harvesting were about 170-188 in September, October, November and December sowings, about 140-155 in August, January and Feburuary sowings, and about 120 in March and July sowings respectively.
    Days after planting to harvesting were about 120 in September and October sowings, 85-100 in August, November and December sowings and about 65-75 in July, January, February and March sowings.
    3. The length and width of the uppermost leaf varied with sowing dates and these were affected principally by temperature. The stem length below the first inflorescence was determined by the temperature during propagation. Thus, it was much shorter in November, December and January sowings than in the other sowings.
    4. Total yields from each sowing over the year were in excess of 7 tons per 10 a, except for cultivar FTVNR-3 sown in October and cultivar Dantobi-Yozu sown in September.
    Percentage marketable fruits was, in both cultivars, as high as 85%, except for cultivar FTVNR-3 sown in October. Cultivar Dantobi-Yozu proved to be more suitable for single truss culture than cultivar FTVNR-3 since it produced stable yield throughout the year.
    5. The daily mean of solar radiation during the growth period and especially that during 30 days after anthesis were found to be highly correlated with the yield; the correlation coefficients being 0.758 (p<0.05) and 0.906 (p<0.001) to total yield and 0.774 (p<0.02) and 0.923 (p<0.001) to yield of marketable fruits, respectively.
    6. For a year-round cropping system of single truss tomatoes, however, seedlings should be planted at the stage just before the first anthesis to shorten the growing period of each crop, which is difficult to practice.
    Performance of three crops over the year is rather feasible by planting seedlings at five or six leaf stage and yet annual yield about 25 tons per 10 a can be obtained.
    7. Year-round culture of single truss tomatoes may increase the efficiency of tomato production and may bring profits to commercial growers, because 1) these plants give an annual yield higher than multi truss plants and their fruit quality is good, 2) the optimal environments are necessary to be kept only for the period of growth and development of the first inflorescence, which will simplify the cultivation and 3) the plants are supported by bar, thus the labour requirement for training is avoided.
    Furthermore, this cropping system makes it possible to make a planting programme over the year with flexibility from a viewpoint of the distribution of labor, and to regulate the production or shipping of tomato fruits taking aim at high price.
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  • Masakatsu MORITA, Shigeharu IWAMOTO, Haruzo HIGUCHI
    1978 Volume 46 Issue 4 Pages 495-500
    Published: 1978
    Released: July 05, 2007
    The mutual effects of thermo-and photo-periodism on growth in Viburnum Awabuki K. were studied.
    1. The chilling treatments (3°C) were applied in autumn and the night temperature in the greenhouse was kept at 18°C under various photoperiods after chilling treatment. When the period of chilling treatment was shorter, such as 0-30 days, growth depended strongly on photoperiod and grew vigorously under long-day and did not grow under short-day. In the case of chilling treatment of 45 days, a symptom of conversion from long-day in to short-day was recognized and grew vigorously under 12 hours of photoperiod. When the period of chilling treatment was longer, such as 60-70 days, the response of growth to short-day was vigorous.
    2. When a high night temperature of 25°C was kept continuously from summer, dependence on long-day was strongest. Long-day caused continuous and vigorous growth but short-day caused periodic and poor growth. When a night temperature of 18°C was kept, long-day caused periodic growth and growth was poor and stopped for a long period under short-day.
    3. The longer the photoperiod was, the more vigorous the growth was. When the night temperature was kept 18°C after a high night temperature in summer, growth stopped under all of the photoperiods in October and growth started again from March to May without chilling and growth was vigorous under long-day and was poor under short-day.
    These results suggest that the response of growth to photoperiod in Viburnum Awabuki K. occurred by interdependence of thermo-periodism.
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  • Shin TAMURA
    1978 Volume 46 Issue 4 Pages 501-508
    Published: 1978
    Released: July 05, 2007
    The present study was carried out in order to pursue some medium constitution and plating method and also the meaning of the difference in the localization about the adventitious bud formation of the hyacinth bulb scale culture.
    Commercial varieties, i.e. ‘La Victoire’, ‘Delft Blue’, ‘Lady Derby’, and ‘Jan Bos’ were used.
    The following results were obtained:
    Hyacinth bulb scales cultured on Murashige and Skoog basic medium, same basic medium plus 0.001 to 0.005mg/l, 2, 4-D and also containing IAA and BA 0.5mg/l respectively showed good adventitious bud formation. In regard to the concentration of 2, 4-D on organogenesis, adventitious bud formation was observed between 0 to 0.1mg/l, especially at very low concentration, and adventitious root formed between 0.001 to 0.5mg/l, especially at 0.01mg/l, whereas callus formed when the concentration was considerably higher, especially at 0.5mg/l.
    The adventitious bud usually formed on the epidermis of the outside of the scale in hyacinth and this feature was contrary in the case of lily where the bud formed on the epidermis of the inside of the scale.
    By the histological observation of adventitious bud formation processes there seemed to be initial cell or cells in the epidermis. However, when the epidermis alone, which was stripped from the scale, was cultured, it showed no bud formation by itself on all the medium used, and the remaining scale without the epidermis formed callus or adventitious root.
    When the method of plating was altered, whether the outside epidermis was on the upper side or bottom side, the bud forming response differed in connection with the constitution of media. Therefore, the localization of endogenous auxins and cytokinins would have an important role in the adventitious bud formation on hyacinth bulb scales, and it was considered that the polarity would exist morphogenetically between the outside epidermis and the inside epidermis, and it can be broken down by some inducing substance.
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    1978 Volume 46 Issue 4 Pages 509-514
    Published: 1978
    Released: July 05, 2007
    1. The weight of corms from plants of which the leaf bases had been wrapped with aluminium foil from the sprouting stage or the three-leaf stage was found to be significantly heavier than that of control corms.
    The difference in weight was maintained up to the end of plant growth. On the other hand, when the sheath leaf was removed, the weight of corms significantly decreased.
    2. A significantly earlier sprouting was observed in corms from plants grown with shading at the leaf base, and corms from plants, from which sheath leaves had been removed, grown with shading at the base of the leaf showed a similar sprouting trend.
    On the contrary, sprouting of corms from plants of which the sheath leaves had been removed, was delayed, as it was in control corms.
    3. The amounts of inhibitors, at Rf valued 0.5-0.8 on paper chromatograms developed with isopropanol ammonium: water (10:1:1v/v), did not decrease in corms from plants without sheath leaves.
    On the other hand, shading of the leaf bases resulted in a decrease of inhibitor at Rf 0.5-0.8.
    4. The extract from leaf bases sampled a week after the shading treatment at the leaf base showed a smaller amount of inhibitors, at Rf 0.5-0.8.
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  • Eisuke MATSUO, Atsushi NONAKA, Ken-ichi ARISUMI
    1978 Volume 46 Issue 4 Pages 515-520
    Published: 1978
    Released: July 05, 2007
    The experiments were carried out to clarify the effects of hot water treatments, the size of the parent scale, or the position of the parent scale in the parent bulb, upon the leaf emergence of the scale bulblet as well as the survival of the parent scale in the Easter lily cv. ‘Hinomoto’.
    The bulbs were treated with 45°C water for 30min. prior to scaling. The parent scales were planted in sandy soil on Aug. 7, 1975 or July 27, 1976 and grown until the last examination on Dec. 21, 1975 or Jan. 19, 1977, respectively.
    Leaves emerged more rapidly on the scale bulblets from the small parent bulb than on those from the large ones. The hot water treatment on the large parent bulb remarkably promoted the leaf emergence of the scale bulblets. In light scaling, the leaf emergence was most rapid on the inner scales and latest on the outer ones. In dark scaling, however, it was most rapid on the middle scales and latest on the inner ones.
    The hot water treatment did not obviously affect the survival of the parent scales. Their survival rate was higher in dark scaling than in light scaling. The survival rate of the parent scales from large bulbs was higher than that from small ones. Independent of the scaling depth or the size of the parent bulb, the survival rate was highest on the inner scale and was lowest on the outer one.
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  • Syoichi ICHIHASHI
    1978 Volume 46 Issue 4 Pages 521-529
    Published: 1978
    Released: July 05, 2007
    The relationships between anionic and cationic combinations relevant to seed population and culture period of Bletilla striata seedlings were shown. Total concentration of the final nutrient media was held to 20 milligram equivalents per liter.
    1. The germination was not much affected by ionic treatments.
    2. The growth of seedlings on a medium was affected by population density. For higher seeding populations, the effect of the medium was significant for the first 10 weeks. That is; the fresh weight and roots per plant were lower. Whereas for lower seeding populations plants were relatively small.
    3. The growth of seedlings in ionic treatments differed with age, and anionic ratios concentrated the optimum at a point.
    4. The requirement for anionic balances was relatively accurate and seedlings grew well at high nitrate levels, whereas that for cationic balances was not clarified. The optimal balances of ions expressed as a percentage of the total ionic concentration in the chemical equivalent were determined as follows; NO3-: H2PO4-: SO4--=60:30:10, and NH4+:K+:Ca++:Mg++=20:40:30:10.
    5. One of the optimal nutrient compositions for the Bletilla striata seedling growth is as follows; NH4NO3 0.320g/l MgSO4•7H2O 0.247g/l KH2PO4 0.817 Sucrose 20 KNO3 0.202 Agar 10 Ca(NO3)2•4H2O 0.945
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  • Kiminori KATO, Ryoji SATO
    1978 Volume 46 Issue 4 Pages 530-540
    Published: 1978
    Released: July 05, 2007
    To clarify the ripening phenomena with special reference to the effect of endogenous C2H4 on respiration in Golden Delicious, Starking Delicious and Fuji apples, fruit samples were taken at 7-14 day intervals with a total of 3 to 6 harvests during the period of maturation and ripening. The rates of respiration and C2H4 evolution, and the internal gas concentrations were measured for 7 to 18 days beginning 1 day after harvest, and the specific gravity and watercore rating were also measured at harvest or 1 day after harvest.
    1. With the exception of late harvested Fuji apples, an increase in internal CO2 concentration corresponded with a rapid increase in internal C2H4 concentration, and with a little delay a rise in respiration occurred. In Starking Delicious apples, a decline in internal CO2 concentration started during the rise in respiration, and there occurred decreases in respiration and internal C2H4 concentration at about the same time, and subsequently a decline in C2H4 evolution began. On the other hand, in Fuji apples a decline in internal CO2 concentration occurred at about the same time as a decline in respiration, and then an internal concentration of C2H4 began to decline, followed later by a decline in C2H4 evolution.
    2. An increase in specific gravity associated with watercore development accompanied a marked decline in internal O2 concentration and an increase in internal CO2 concentration. In Fuji apples, as harvest was delayed, there was an increase in specific gravity with a corresponding increase in the internal concentration of C2H4 at 1 day after harvest. Late harvested Fuji apples, which had a high specific gravity and severe watercore, exhibited little or no rise in respiration even if there occurred a rapid increase in internal C2H4 concentration, which was not observed in the case of a low internal concentration of O2.
    3. It is considered from these data that C2H4 elevates the rate of respiration and induces the climacteric rise in respiration, but the increase in specific gravity or the development of watercore causes changes in gas permeability and solubility of apple tissues, and thereby exerts great influence on the rates of respiration and C2H4 evolution, and the internal gas concentrations as well as the effect of C2H4 on respiration.
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  • Kazuhiro ABE, Kuniyasu OGATA
    1978 Volume 46 Issue 4 Pages 541-547
    Published: 1978
    Released: July 05, 2007
    This paper reports the ultrastructural changes associated with chilling injury of eggplant fruits based on the electron microscope.
    1. By using an electron microscope it was observed that cytoplasm in epidermal cells of eggplant fruit had little difference from other fruits and vegetables in general. Parenchyma cells had less cytoplasm than epidarmal cells beside the cell wall and the ultrastructures of cytoplasm were the same as those of the cytoplasm in epidermal cells.
    2. The ultrastructural changes and cell wall burst of epidermal and parenchyma cells did not occur after 9 days′ storage at 20°C. Eggplant fruit showing no pitting injury after 4 days′ storage at 1°C showed ultrastructural changes of cytoplasm in parenchyma cells such as partial degradation of tonoplast and swelling of mitochondria. The epidermal cells of the pitting portion in eggplant fruit after 9 days′ storage at 1°C displayed no cell wall burst but nuclear membrane, mitochondria, and ground substance had ultrastructural changes. The parenchyma cells of the pitting portion in eggplant fruit after 9 days′ storage at 1°C showed cell collapse without cell wall burst and ultrastructural changes such as degradation of tonoplast and swelling of mitochondria having irregular distribution of cristae in them. In the parenchyma cells near the pitting portion, no cell wall burst occurred but tonoplast, mitochondria, and ground substance had slight changes which bore resemblances to the changes in the pitting portion.
    3. In the parenchyma cells of the pitting portion, globules which showed parallelogram cut were observed in vacuole sap. Each globule usually contained a cross shape which was relatively high-electron dense.
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  • Kyuei IINO, Kazuo OSODO
    1978 Volume 46 Issue 4 Pages 548-554
    Published: 1978
    Released: July 05, 2007
    Based on the data of organoleptic evaluation of commercial satsuma mandarin, statistical analysis was carried out to clarify the relationship of palatability with refractive index (Bx) and pH value, and further to investigate sampling for grading inspection.
    (1) The palatability for the mandarin being highly complex, a multiple regression equation consisted of six terms was reasonable as follows:
    Palatability=a0+a1(logBx)+a2•pH+a3•(logBx)2+a4•(pH)2+a5•logBx•pH Where a0-a5were constants dependent on seasons.
    (2) The accuracy of the equation was high even when an organoleptic evaluation was carried out with a different panel and using the mandarins in a different crop year.
    (3) The palatability pattern of the mandarin was visualized by means of the contour lines of organoleptic value on the plane consisting of Bx and pH axis.
    (4) The palatability pattern changed depending on the season. The sweetness of the oranges was favored in the season of the early ripening variety, and of usual ripening variety, but the range of optimal pH to the Bx of the latter was narrow. On the contrary, sourness was preferred for the stored fruits. It was considered that the palatability pattern continuously changed with the seasons: from autumn to winter to spring.
    (5) The mean value of Bx and pH of ten samples selected at random was not so significantly different from the population mean. Therefore, ten samples seemed enough in number for grading inspection. Moreover, measuring once the combined juice from ten samples was appropriate for the inspection, and the “one by one” method seemed unnecessary.
    (6) According to JIS Z 9003 standard, the risk which either manufactures or consumers suffer is respectively 10% and 5%, therefore the Bx and pH values, subtracting 0.5 and 0.15 from the measured values, are adequate for grading.
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  • Masatoshi MANABE, Hisayoshi KAMIKAWA, Takayuki TARUTANI
    1978 Volume 46 Issue 4 Pages 555-560
    Published: 1978
    Released: July 05, 2007
    Astringent persimmons (Yokono cv.) were peeled and then sun-dried under usual weather conditions. The mechanism of astringency removal was examined, with particular attention given to the relation between gas exchange and the insolubility of soluble tannin in fruit. The amount of soluble tannin in persimmons decreased markedly during seven to nine day′s drying and the organoleptic test for astringency was almost negative. The fruit weight decreased about 45% during this period.
    1. The amounts of oxygen intake and carbon dioxide production from dried persimmons decreased markedly from the third to ninth days, after which the decrease was more gradual. On the other hand, in astringent persimmons dried with peels, in which astringency did not disappear, the amount of the above gases remained nearly constant through nineteen days of drying.
    2. Alcohols (containing both of methanol and ethanol) increased in percentage by weight as the persimmon dried, but the percentage remained almost constant when calculated relative to the original fresh fruit weight. The alcohol content was considerably greater than that of aldehyde from the beginning of the drying period. It is concluded that these alcohols do not affect the removal of astringency.
    3. Acetaldehyde was small in quantity in the fresh fruit, but during the first four weeks of drying it increased considerably to a value equal to that of the original fresh fruit weight.
    4. From these results, it can be concluded that the removal of persimmon astringency by sun drying is due to the reaction between soluble tannin and acetaldehyde which is formed by incomplete respiration due to the membrane formed on the fruit surface during drying and to the degradation of fruit tissues.
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