Journal of the Japanese Society for Horticultural Science
Online ISSN : 1880-358X
Print ISSN : 0013-7626
ISSN-L : 0013-7626
Volume 60 , Issue 2
Showing 1-26 articles out of 26 articles from the selected issue
  • Shin Hiratsuka, Yohko Kitoh, Jiro Matsushima
    1991 Volume 60 Issue 2 Pages 257-265
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Aberrations in pollen tube tips of Japanese pear, Pyrus serotina, in vivo studies following pollen-incompatible and -compatible pollinations; and in vitro studies on the effects of chemical additives to the growth medium were investigated.
    Incompatible and compatible pollen/stigma-style combinations resulted in pollen tubes with deformed tips which were mainly detected as a swelling. The incompatible combinations developed approximately twice as many swollen tips. Their surface structure revealed irregular features such as concave and unusual furrows, whereas a smooth surface was observed in normally growing tips.
    In in vitro trials, ABA, ovarian extract (OE), polyethylene glycol (PEG), H3B03 and fusicoccin (FC) increased the number of abnormal pollen tube tips. The tip surfaces of these tubes were considerably irregular, except in the case of H3BO3, which seemed to be similar to those deformed tips observed in incompatible styles. Boric acid caused regular fine furrows along the tube axis but CaCl2 had no effect on the deformed tip formation; the tube surface structure was relatively smooth. Thus, the growth inhibitors tend to induce irregularities on pollen tube surface similar to those observed on pollen tubes growing in an incompatible style, whereas growth promoters did not induce such symptoms. The similarities in tip morphology may indicate that cell wall synthesis in pollen tubes growing in incompatible styles is altered by inhibitors or water stress following a specific recognition reaction on the stigmatic surface and/or in the transmitting tissue. This alteration causes cessation of tube growth.
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  • Hisashi Yamada, Keiko Nakajima, Yasuhide Yamazawa, Isaku Kuroi
    1991 Volume 60 Issue 2 Pages 267-273
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Self- and cross-compatibility of pollens and the effects of pollination and gibberellins on fruit set, physiological drop, growth, and maturation of 'Le Lectier' pears were investigated to clarify the characteristics of fruit bearing.
    1. Self-pollinated pollen tubes stopped growing at about 4 mm below the stigmatic surface, whereas cross-pollinated ones reached the base of the styles within 3 days after pollination.
    2. Fruit set of self- or non-pollinated flowers was under 15%, whereas that of crosspollinated ones exceeded 40%. Treatments with both 200 ppm GA3 sprays one day before pollination and GA3+4+7 paste applications 5 weeks after pollination increased fruit set of both self- and non-pollinated flowers to 30%.
    3. Physiological fruit drop ("June drop") in self- or non-pollinated group reached a maximum 3 weeks after anthesis, thereafter the rate of abscission was relatively high for 4 more weeks. Fruit drop of the cross-pollinated lot reached a maximum 5 to 6 weeks after pollination. Fruit drop of GA-treated flowers from all pollinated groups exhibited a wave of abscission similar to that of the cross-pollinated control lot.
    4. Fruits resulting from cross-pollination were larger at harvest than were those resulting from self- or non-pollination. GA applications resulted in longer fruits with a protruding calyx and hastened chlorophyll degradation compared to the non-treated control fruits. Fruits of the self- or non-pollinated groups contained a few or no seeds, whereas, those of from the cross-pollinated lot had 7 to 8 seeds per fruit.
    5. The time of ethylene evolution during the ripening period was advanced by GA treatment.
    6. Emasculation had no effect on fruit set and development.
    These results indicate that the pollen of 'Le Lectier' pear is highly self-incompatible and the cultivar has a weak tendency to form parthenocarpic fruits. GA induces the setting of parthenocarpic fruit and stimulates fruit maturation possibly by advancing the time of ethylene evolution.
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  • Hiroshi Inoue, Yoshinori Ikoma, Ikuo Kataoka
    1991 Volume 60 Issue 2 Pages 275-284
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effects of ringing with or without hand defoliation on vegetative growth, flower bud differentiation, and physiological changes in young, container-grown satsuma mandarin (cv.Okitsu Wase) on trifoliate orange were investigated. Comparisons were made between trees grown under different temperatures in a growth chamber and those grown in the field. A ring of bark, 3 mm wide was removed 5 cm above the bud union. The wound was wrapped with a vinyl tape to prevent drying and to enhance callus development.
    1. Ringing in mid-June, after the spring growth flush ceased root growth within several days. After the ringing wound healed, new roots developed but the onset of the summer flush was delayed and shoot growth was depressed. Ringing in early September, after the summer flush stopped, not only depressed root growth, but it also prevented the initiation of new roots even though the girdles callused over. The absence of new roots is attributed to the lower air temperature in autumn. The autumn flush of new growth did not occur on treated trees.
    2. Potted trees were ringed in either mid-June, late July, or mid-September. Ringed and non-ringed trees were defoliated, and then transferred to a 25°C growth chamber at intervals of 1.5 months. Number of flowers and vegetative shoots which emerged after defoliation was observed. Defoliation in mid-June of non-ringed control trees required new growth over 10 days. When trees were defoliated in late July, bud break occurred within several days.However, trees required more days again in mid-September, and the maximum of 20 days in late October for bud break after defoliation. Trees ringed in mid-June and defoliated in late July, mid-September, or late October required 15, 9, and 17 days, respectively, to initiate regrowth. Ringed trees in July or September caused regrowth similar to that of non-ringed trees. Trees defoliated in early December, girdled in July or September, and held at 25°C produced many flowers, whereas those ringed in June produced few flowers.
    3. Trees, ringed on 1 September, and non-ringed trees were held at 15°, 20°, and 25°C in growth chambers or planted in the open field. The girdle produced more callus and healed faster at 25°C than at 20°C; no callus formed at 15°C. When trees at 25°C were defoliated in early December and kept at the same temperatures, bud break was delayed compared to those which were transferred to lower temperatures. Non-ringed trees held at 25°C produced few flowers, whereas ringed trees bloomed profusely. With or without girdles, trees kept at 15° and 20°C produced many flower buds; girdled trees kept at all temperatures had more flowers per sprouting node than did non-girdled ones.
    4. Analysis of leaves from non-girdled trees growing in the field and from those girdled on 1 September revealed that the sugar content in all samples increased in autumn. The in-crease is attributed to the low air temperatures. After ringing, leaf starch content increased to over 20% (dry weight basis) and then decreased. Nitrogen content decreased linearly until the wound callused over and then the level increased. The C/N ratio increased until the wound healed and then decreased. Transpiration resistance of the leaves was temporarily greater on ringed trees; the upward movement of the transpiration stream was, therefore, slower until the girdle healed.
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  • Hiroshi Inoue, Yoshinori Ikoma
    1991 Volume 60 Issue 2 Pages 285-290
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effects of autumn ringing, and 6-benzylaminopurine (BA) sprays on flower bud differentiation and development, and physiological changes in one-year-old satsumas (cv. Okitsu Wase) on trifoliate orange growing in a growth chamber were investigated. On 1 September, half of the trees was ringed by removing a 3-mm wide ring of bark, 5 cm above the bud union. Of the ringed group, half of the trees had the wound covered with a vinyl tape to hasten callus formation; the rest had the girdle left uncovered so that the wound would not heal. Subsequently, one lot of ringed and a lot of non-ringed control trees were kept at 25°C for 3 months; comparable lots of trees were kept at 25°C for one month and then placed in a 15°C chamber for two months.
    On 1 December, all trees were defoliated, and then placed in a 25°C chamber. The non-healed trees kept at 25°C for 3 months delayed on flushing, and decreased on the percentages of sprouting nodes and produced a few flowers. The healed ones produced many flowers.The trees chilled at 15°C for 2 months were not influenced on flushing by ringing and produced many flowers. Chlorophyll content in leaves from trees with open girdles was loWer, and starch and free proline contents in these leaves were higher than those on non-ringed trees or on those trees with healed girdles. Two applications of 200 ppm BA resulted in increased numbers of flower and vegetative buds and advanced budbreak. However, breaking of bud dormancy by BA sprays was incomplete.
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  • Kojiro Hasegawa, Yoshikazu Nakajima
    1991 Volume 60 Issue 2 Pages 291-299
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The experiments were conducted to determine what effect strapping lateral branches with covered, insulated wires (partial girdling) had on fruit set and quality in the same season and flower formation for the second year. Seven-year-old Japanese persimmon trees, cvs. Saijo and Maekawa-Jiro which were bearing light crops were used. Concurrently, how painting KT-30 (N-2-chloro-4-pyridyl-N' -phenylurea) on buds in summer affects bud break and flower formation for the following season was examined.
    1. Percentages of fruit set in cvs. Saijo and Maekawa-Jiro were increased significantly by the strapping treatment made on 10 June. Fruit size of 'Saijo' was enhanced and the yellow pigment concentration of both cultivars was intensified and the soluble solids content of 'Maekawa-Jiro' was increased by the treatments made on 10 June and 1 July.
    2. Strapping branches on 10 June increased the number of flowers threefold and tenfold, respectively, on 'Saijo' and 'Maekawa-Jiro'. Strapping branches on 1 July increased flower density over that of the control but it was less than that of branches strapped on 10 June. Both treatments resulted in fewer and shorter lateral branches in both cultivars as compared to control limbs.
    3. The yields in the year of the treatment and the following one were increased by the girdling effect. The yield on branches strapped on 10 June was greater than was that of branches treated on 1 July because branches treated on the former date had a higher percent fruit set than did those treated on the latter date.
    4. Compared to the control untreated limbs, the number of flowers initiated was not increased by painting buds with KT-30.
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  • Hirokazu Fukui, Yoshiaki Wakayama, Mitsuo Nakamura
    1991 Volume 60 Issue 2 Pages 301-307
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Embryo and endosperm development was histologically observed to seek the cause of seed abortion in Japanese persimmon 'Nishimurawase'. Four seeds each from 30 open-pollinated fruits were collected periodically from anthesis to 60 days later. Seeds were fixed and their sections studied microscopically.
    1. The fertilized egg which began to divide 16 days after anthesis developed into proembryos two weeks later. The embryos became globular 40 days after anthesis and then became torpedo-shaped 10 days later. Cotyledonary embryos were 3.0 mm in length 60 days after anthesis.
    2. The primary endosperm nucleus began to divide 4 days after anthesis; nearly all endosperms underwent cellular endosperm stage from a free nuclear division stage 30 days after anthesis.
    3. Three types of abnormality in seed developments were observed; a) the embryosac:b) abnormal free nuclear division in the endosperm: Free nuclear division of endosperm either did not occur or it was delayed (18%) ; and c) endosperm abortion.
    Embryosac abnormality fell into three categories; 1) degeneration (16%) ; 2) two or more embryosacs were formed (15%) ; and 3) incomplete embryosac at anthesis (3%).
    4. Seeds with abnormal development of embryosac and abnormal free nuclear division of endosperm did not enlarge at the same rate as did those which were normal. Therefore, abnormal seeds were distinguishable from normal one by their lengths about 20 days after anthesis. Seeds (11%) in which the endosperm quit enlarging after cellular endosperm stage were smaller than normal ones but larger than those in which the embryosac or the endosperm aborted during its free nuclear division stage.
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  • Haruki Komatsu, Shoichi Nakagawa
    1991 Volume 60 Issue 2 Pages 309-317
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effects of dipping flower clusters before bloom in solutions of various plant growth regulators (GR) on the setting of parthenocarpic and seeded berries in 'Kyoho' grape were studied. The effects of a) dipping immature rachis in 2, 500 ppm succinic acid-2, 2-dimethyl hydrazide (SADH) and b) severe winter pruning on the content of endogenous plant growth substances in florets were also examined. The 'Kyoho' vines were trained to a vertical espalier and the pergola trellis systems.
    1. Dipping flower clusters in plant growth retardants, ((2-chloro-ethyl) trimethyl ammonium chloride) (CCC) and SADH significantly increased the set of seeded berries as compared to the control clusters. Among different dosages of GR, 2, 500 ppm SADH was most effective, independent of the training system; applications of growth promoters were ineffective in setting seeded berries. SADH also increased the number of seeds per berry, especially on vines trained to an espalier system.
    2. Severe pruning resulted in a high percentage set of seedless berries.
    3. An application of SADH decreased gibberellin (GA) and increased abscisic acid (ABA) contents in florets. Contrarily, severe pruning resulted in a rapid increase in GA level at bloom and a decrease in ABA content. The amount of cytokinins and indole-3-acetic acid (IAA) in florets also changed with these treatments. The amount of cytokinins increased with SADH treatment, but the relationship between the setting of seeded berries and the level of cytokinins and IAA in florets could not be established.
    These results suggest that poor berry setting in 'Kyoho' can not be explained by the theory of nutritional competition between cluster development and shoot growth. That endogenous plant growth substances, especially GA and ABA, in the florets are closely associated with the setting of seeded berries became evident in this study.
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  • Yoshihiro Shishido, Yutaka Hori
    1991 Volume 60 Issue 2 Pages 319-327
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The role of leaf as affected by phyllotaxis and leaf histology on development of individual fruit on an inflorescence and fruit development as a whole were investigated by the transport and distribution patterns of 14C-assimilates in tomato.
    Tomato plants have alternate with four orthostichies with divergence of 90° (270°) and 180°, and floral axes of raceme situate on one orthostichy. The 1st and 3rd fruit was situated on one side of the peduncle, and the 2nd and 4th fruit was situated on the opposite side of the peduncle.
    The percentage of distribution of 14C-assimilates and RSS (Relative strength as a sink) to the 1st and 3rd fruit of an inflorescence were higher than those of 2nd and 4th fruit from the leaf which was situated just below the inflorescence and on the same side to the 1st and 3rd fruit.
    Furthermore, the distribution pattern indicated that the leaf just above the inflorescence exports 14C-assimilates to the fruit on the inflorescence as well as the leaf below the inflorescence but located on the opposite side to the inflorescence.
    The distribution pattern from the leaf on a lateral branch indicated that the inflorescence of the main axis still act as a large sink. However, the RSS values for the leaf on a lateral branch revealed that the inflorescence on the lateral branch was a stronger sink than that on main axis. Since fruit developing stages differ in those inflorescences, fruit size and weight should be different, which heavily contribute to the percentage of distribution to each inflorescence. Therefore, it sometimes happens that the percentage of distribution and the RSS value do not always go together.
    From these results, the accumulation of 14C-assimilates to an inflorescence is likely affected by their proximity to the source leaf, their developmental stage and the connection of vascular system in the stem.
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  • Yoshiteru Sakata, Takeshi Nishio, Tomoaki Narikawa, Shinji Monma
    1991 Volume 60 Issue 2 Pages 329-335
    Published: 1991
    Released: May 15, 2008
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    Cotyledon mesophyll protoplasts of tomato 'Ponderosa' were fused with mesophyll protoplasts from true leaves of L. peruvianum, using polyethyleneglycol (PEG) solution and the fusion products cultured in vitro. Somatic hybrids were selected by morphological characteristics of shoots which differentiated on the calli. Ribosomal DNA of the selected plants was analysed and four plants were confirmed to be somatic hybrids. Pollen viabilities of four somatic hybrids were 78.3, 62.2, 60.2, and 36.2%, respectively; the hybrids were all self-fertile. The seedlings of tomato 'Ponderosa', L. peruvianum, and the offsprings of two somatic hybrids were used in growth analysis under low temperature condition. Relative growth rates of the somatic hybrids under low temperature regimen were less than that of L. peruvianum but greater than that of 'Ponderosa'. This investigation demonstrated that the charactor of cold tolerance was introduced from L. peruvianum to the somatic hybrids. The offsprings of the somatic hybrids also showed resistance to tobacco mosaic virus and tomato spotted wilt virus.
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  • Katsumi Ohta, Norihiro Ito, Takashi Hosoki, Yoshihiko Sugi
    1991 Volume 60 Issue 2 Pages 337-343
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The influence of relative humidity on fruit cracking of cherry tomato grown hydroponically and how this problem might be alleviated by ventilation were studied. The cherry tomato 'Sun Cherry' and 'Akakokko' were cultured at three relative humidity regimens; untreated control, low, and high.
    1. Compared to the control, the percentage of cracked fruits was decreased by low humidity and increased by high humidity. The lengths of cracks were short and the ratio of crack lengths to fruit circumference expressed as a percentage (% L/C ratio) was small under low humidity, whereas they were the reverse under high humidity. As for fruit firmness, the penetrating stress and resistance of both skin and flesh and tensile stress of the skin were greater under low humidity than they were under high humidity. These data indicate that fruit texture became firm in the low humidity regimen.
    2. The ambient atmosphere about the two tomato plants was ventilated to decrease the relative humidity. Fruit cracking was reduced by ventilation; that is, crack lengths shortened and the % L/C ratio decreased. The penetrating stress and resistance of both skin and flesh was increased by ventilation, suggesting that aeration probably reduced the relative humidity and thereby caused the fruits to become firmer compared with the unventilated control fruits.
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  • Yuichi Yoshida, Tanjuro Goto, Toshiaki Chujo, Yukihiro Fujime
    1991 Volume 60 Issue 2 Pages 345-351
    Published: 1991
    Released: May 15, 2008
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    Changes in anatomy and receptivity of pistils of strawberry (Fragaria × ananassa Duch.) cv. Ai-Berry and Nyoho after anthesis were investigated.
    1. In the cymose truss of the 'Ai-Berry', the distal pistils of the primary (first) flower to open are small and immature, whereas proximal pistils near the base of the receptacle are fully mature and receptive to pollen. In some cases, the stigma of distal pistils are not receptive even 10 days after anthesis. Contrarily, on the tertiary (5th) flowers of 'Ai-Berry' and primary flower of 'Nyoho', the differences in size and the stage of development between the distal and proximal pistils are small and the pistils are equally receptive to pollen at anthesis.
    2. The number of undeveloped distal achenes on the fruit decreased if pollination was delayed in 'Ai-Berry', but the stigma on the basal pistils lost their receptivity 4 days after anthesis. Thus, on flowers pollinated 4 or more days after anthesis, the basal pistils failed to set seeds and developed poorly, giving rise to malformed fruits.
    3. Malformed fruits in 'Ai-Berry' may be reduced by controlling the timing and the duration of the pollination period, but this is difficult because of the wide range in pistil maturity from the apex to the base of the receptacle. To overcome this problem of malformation in 'Ai-Berry', cultural conditions which might narrow this range during flower development need investigation.
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  • Yuichi Yoshida, Megumi Suzuta, Yukihiro Fujime, Toshiaki Chujo
    1991 Volume 60 Issue 2 Pages 353-359
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Differences in floral and fruit characteristics of strawberry (Fragaria×ananassa Duch.), were investigated, especially with respect to the relationship between the maturity of pistils at anthesis and the final fruit shape. The primary (first), secondary (third) and tertiary (5th) flowers on the single truss on six cultivars: Ai-Berry, Hokowase, Reiko, Toyonoka, Nyoho, and Morioka No. 16 were examined.
    1. The primary flower of 'Ai-Berry' had the largest number of rows of pistils from the base to the apex of the receptacle; the others had about the same number of rows of pistils. At anthesis, ovaries on the distal region of the receptacles were small and still immature; those of 'Hokowase' were intermediate in size, whereas the ovaries of the remaining 4 cultivars were large and mature. The ratio of ovary daimeter on the apex and base of receptacle (T/B ratio) was significantly smaller in 'Ai-Berry' when compared with the others. There were high correlations between fruit malformation due to poorly developed achenes on the distal end of the fruit with a) the number of rows of pistils; b) diameters of ovaries of pistils on the apex of receptacles at anthesis; and c) the T/B ratio.
    2. In 'Ai-Berry', there was a negative correlation between the number of rows of pistils and the diameter of the ovaries on the apex of receptacle. A similar correlation exist in 'Hokowase' which is the pollen parent of 'Ai-Berry'. Therefore, 'Ai-Berry' may have inherited the wide range of pistil maturity from the apex to the base of receptacles at anthesis from 'Hokowase'.
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  • Shinichi Adaniya
    1991 Volume 60 Issue 2 Pages 361-367
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Zingiber mioga Roscoe (2n=55), a condimental vegetable, rarely sets seed. To activate a breeding project, the effects of the pollination season and relative humidity on the seed setting potential were examined under long day (16 hr) conditions. The variation in the number of chromosomes of self-pollinated progenies was also investigated.
    In the spring of 1987, only five seeds set in four ovaries obtained from 190 florets pollinated with fresh pollens. In the winter of 1988, 84 seeds set in 26 ovaries obtained from 184 pollinated florets. In the spring of 1989, the seed setting capacity of plants was compared between those grown in a fully open, plastic house under natural humidity and those grown in a partially open, humidified plastic one. In the latter, high relative humidity was maintained with a humidifier. No seed set in any of 45 florets pollinated under natural humidity conditions, whereas 73 seeds set in 23 ovaries obtained from 121 florets pollinated under humidified conditions. Embryos were excised from 73 and 69 seeds obtained in the winter of 1988 and in the spring of 1989, respectively. These embryos were cultured on MS medium containing 30 g/liter sucrose from which 106 plants were raised. Of the 67 plants examined, the chromosome number varied from 2n=46 to 2n=60.
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  • Hegazi H Hegazi, Sachiko Matsubara
    1991 Volume 60 Issue 2 Pages 369-377
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Fertility and morphological characteristics of interspecific and intergeneric hybrids between radish, cabbage, and Chinese cabbage were compared with those of the parents. Because some hybrid progenies were sterile, they were propagated vegetatively through in vitro culture. Hypocotyl segments were imbedded on MS medium containing combinations of two phytohormones: 2, 4-D plus BA or kinetin, or NAA plus BA or kinetin. The synthetic auxin and cytokinin concentrations were 0.1 and 1.0 mg/liter, respectively. For plant regeneration, callus obtained from the hypocotyl was subcultured at monthly interval on a callus initiation or MS media with or without cytokinins.
    1. Reciprocal hybrids showed considerable variations in their morphological characters.
    2. Both parents and hybrid progenies formed callus on the MS medium supplemented with auxins and BA and the subculture medium containing BA.
    3. About 6% of the interspecific radish explants regenerated shoots on the initial medium; none was obtained in the first and second subculture media. From 5067% of the calli from intergeneric hybrids between cabbage and radish yielded shoots on the initial medium; 1666% and 1020% of the calli formed shoots on the first and second subculture, respectively. As much as 70% of the calli from interspecific hybrids between cabbage and Chinese cabbage formed shoots on the initial medium; 3060% of the calli regenerated shoots when subcultured. Variations in callus size and weight obtained from parents and their progenies as a result of reciprocal crosses indicated that the ability to form callus and to regenerate shoots from calli was controlled by different genetic factors.
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  • Yasutaka Kano, Nobuyuki Fukuoka
    1991 Volume 60 Issue 2 Pages 379-386
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Hollow root, a physiological disorder, which is manifest by the lengthwise hollowing of the central stele of Japanese radish root, has been frequently associated with the summer-sown crop. The present study sought the relationship between the occurrence of hollowness and the stage and rate of root growth that were manipulated by changing plant density and thinning time.
    1. Root growth was relatively slow for the first 21 days after sowing and then became rapid. Large xylary vessels became aligned radially in the central region of the root 7 days after sowing. Continued cell division in the central region caused the vessels to separate into two diametrically opposite groups producing a space between them as the separation progressed. Intercellular air spaces formed among parenchymatous cells in the central region 21 days after sowing. Hollow zones appeared 28 days after sowing as these air spaces coalesced and enlarged, concurrent and proportionate to the increase in root growth.
    2. The mean root weight increased significantly when plant density was reduced early in the growing period instead of late. Anatomical observations made at harvest revealed that the space between vessel sectors in the central region of the root, the space among vessels in the outer region and the size of parenchymatous cells were larger in roots from early thinned plots than were those from the later thinned plots. Hollow roots were more prevalent in plots thinned early, whereas they were rare in roots harvested from those plots which were thinned 31, or more days after sowing.
    Therefore, it is surmised that the intercellular air spaces that develop in young roots coalesce into longitudinal pockets when vessel groups separate diametrically by rapid thickening of the root. The rapid growth is attributed to active division and enlargement of parenchymatous cells during' the maturation period. Conversely, the separation of vessel groups is suppressed and the hollow air spaces do not develop as root growth is inhibited by high plant density.
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  • Genjiro Mori, Hideo Imanishi, Yoshihiro Sakanishi
    1991 Volume 60 Issue 2 Pages 387-393
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The growth periodicity of Hymenocallis plants grown outdoors and the effect of temperature on the initiation and development of flower buds were investigated.
    1. Hymenocallis bulbs have a sympodial branching system with each unit of the sympodial branch consisting of a membranous scale and about 17 foliage leaves in 1/2 alternate arrangement from the base upwards. The apex terminates in an inflorescence bearing about 5 florets.
    2. Shoot apices of plants grown outdoors were in the vegetative state in early October; they began to flatten and broaden in early to mid-October. Subsequently, the outer and inner tepal primordia of the first floret appear by the year's end. Further development of flower buds is resumed in late April when stamen initials appear. In early June the carpel primordia of the first floret of an inflorescence become evident. Pollen formation occurs in early or mid June and the flower blooms in early August.
    3. Flower formation was inhibited when plants were held at 25°C after 1 July but it was promoted when plants were transferred to 15° or 20°C. After flower buds were initiated, plants kept at 25°C flowered earlier but they had smaller florets and shorter scape length than did those held at the cooler temperatures.
    4. In a commercial forcing trial, flowering in late May, which is two months earlier than the natural flowering time, was attained by keeping plants at a min. of 20°C after the end of November. Moreover, by exposing plants to a photoperiod of a 16-hr day and maintaining them above 20°C from the end of September, the plants bloomed in mid-April.
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  • Takashi Hosoki, Morihiko Hamada, Takumi Kando, Ryouji Moriwaki, Kunio ...
    1991 Volume 60 Issue 2 Pages 395-403
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Flowers of the tree peony, Paeonia suffruticosa, and its interspecific hybrids with P. lutea, and P. delavayi, which originated in China and which were introduced by American and French breeders, were assayed for anthocyanins to trace their development.
    Petal hues of all Japanese cultivars (Paeonia suffruticosa) were distributed within the blue-red scope on Commision Internationale de l'Eclairage (CIE) (L*, a*, b*) color coordinate. Red-dish purple cultivars had high values of both blue and red, whereas pink or white cultivars had low values. Dark red or deep red-purple cultivars contained a large amount of anthocyanins in the petals, whereas pink or white cultivars contained a slight amount. Therefore, there was a high negative correlation between petal lightness (Hunter's L value) and petal anthocyanin contents.
    All dark red or deep red-purple Japanese cultivars contained 6 anthocyanins, peonidin 3, 5-diglucoside (Pn3G5G), peonidin 3-glucoside (Pn3G), cyanidin 3, 5-diglucoside (Cy3G5G), cyanidin 3-glucoside (Cy3G), pelargonidin 3, 5-diglucoside (Pg3G5G) and pelargonidin 3-glucoside (Pg3G). Vivid red cultivars lacked Cy3G/Cy3G5G but contained large amounts of Pg3G/Pg3G5G. Some pink cultivars lacked Pn3G and Pg3G as well as Cy3G/Cy3G5G.
    Of the 6 anthocyanins present in the Japanese cultivars, the Chinese cvs. of P. suffruticosa and P. suffruticosa var. spontanea generally lack Pg3G, which may account for the absence of the vivid red color.
    American and French interspecific hybrids between P. suffruticosa and P. lutea and P. delavayi lack Pg3G and Pg3G5G. The lack of pelargonidins gave rise to hybrids with crimson or scarlet flowers; but in the presence of a yellow chalcone, peonidin and cyanidin in some cultivars gave rise to orange or maroon flowers. The yellow pigment is inherited from the P. lutea and P. delavayi.
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  • Kiyoshi Ohkawa, Yoshihiro Ishihara, Hiroshi Hyodo, Atsushi Kano
    1991 Volume 60 Issue 2 Pages 405-408
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    A spray application of ethrel (ethephon, 2-chloroethylphosphonic acid) at 100 ppm to sweet pea plants induced large numbers of developing flower buds to abscise, whereas that at 25 ppm caused a few buds to abscise. When 0.4 mM silverthiosulfate (STS), an inhibitor of ethylene action, was sprayed immediately following the ethrel application, bud abscission was strongly inhibited.
    The rate of ethylene evolution by the buds resulting from the 25 ppm ethrel treatment was low; at 100 ppm, a rapid rate of ethylene evolution was observed 3 to 4 days after the treatment. When 0.8 mM STS was applied concurrently with ethrel or 48 hr later, the subsequent rate of ethylene production was strongly suppressed.
    From these results, we consider the induction of autocatalytic ethylene synthesis by ethreltreated sweet pea plants to be responsible for flower bud abscission.
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  • Ikuo Miyajima, Toshiya Maehara, Tetsuro Kage, Kunimitsu Fujieda
    1991 Volume 60 Issue 2 Pages 409-414
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The principal yellow pigment in petals of yellow-flowered cyclamen found in the inbred line of diploid cultivar of white-flowered cyclamen was isolated and identified chromatographically and spectrophotometrically as chalcononaringenin-2'-glucoside (isosalipurposide).
    This mutant clone seems to lack the same recessive enzyme chalcone-flavanone isomerase as the mutant of Callistephus chinensis. The prospects on the breeding for deep yellow-colored cyclamen are discussed.
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  • Hajime Ohno
    1991 Volume 60 Issue 2 Pages 415-420
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Ethephon, one of the chemicals releasing ethylene, induced flower bud blasting of a Cymbidium hybrid (C. ×Sazanami 'Haru-no-umi') regardless of the stage of flower buds. Both silver-thiosulphate (STS) and gibberellic acid (GA3) overcame the inhibition of flower bud development induced by high temperatures. There was, however, a distinct difference in the action between these chemicals. The stimulation of flower bud development by STS remained after subsequent applications of ethephon; that of GA3 was nullified by ethephon. Furthermore, inflorescences treated with STS evolved more ethylene than did the control, whereas inflorescences treated with GA3 evolved less ethylene than did the control. These results indicate that STS and GA3 function as inhibitors of ethylene action and ethylene synthesis, respectively. They also indicate that ethylene is involved in high temperature-induced blasting of Cymbidium flower buds.
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  • Kenji Yamane, Saneyuki Kawabata, Ryozo Sakiyama
    1991 Volume 60 Issue 2 Pages 421-428
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Changes in water relations, carbohydrate contents, and acid invertase activity in expanding gladiolus perianths on cut stems were studied.
    1. The specific rate of elongation of the perianth was fastest just before anthesis, but slowed down while the floral organs unfolded; it approached zero as the perianth became fully expanded.
    2. Pressure potential of tissue water was high while the perianth was growing rapidly.
    3. Fructose and glucose were the predominant soluble sugars in the perianth. These solutes were considered to contribute to the low osmotic potential of perianth tissues during their elongation process.
    4. Acid invertase activity of perianth tissue was correlated to the specific rate of elongation. There was no correlation between the enzyme activity and the growth rate when the perianth was wilting.
    5. Starch in florets was considered to be the primary source of soluble carbohydrates which contribute to the early stages of flower expansion.
    6. At the wilting stage, soluble sugars were probably translocated from the perianth to other organs.
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  • Tomoaki Matsuo, Makoto Kinoshita, Saburo Itoo, Kayoko Shimoi, Yoshihid ...
    1991 Volume 60 Issue 2 Pages 429-435
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    With the purpose of developing a new industrial utilization of kaki-shibu, antimutagenic activity of kaki-tannin purified from kaki-shibu on UV-induced mutagenesis was examined and reported in this paper. The activity was evaluated by counting the number of revertant colonies (Trp+) from a strain of Escherichia coli B/r WP2 (Trp-) in media + kaki-shibu fractions after ultraviolet (UV) irradiation.
    1. Although kaki-shibu powder itself did not give any large effect on UV-induced mutagenesis, a kaki-shibu residue from which tannin had been removed and a purified kaki-tannin from kaki-shibu at a mg per agar plate, respectively, yielded a 58% and 72% relative mutagenic activity (RMA). A mixture of chemically degraded products from kaki-tannin at a mg per plate resulted in a 37% RMA, a significant antimutagenic potential.
    2. Purified kaki-tannin (10 g), degraded in an acidic ethanol-phloroglucinol solution by heating at 80°C for 3 days, resulted in four monomeric phloroglucinol-derivatives. Their arbitrary labels based on their order of Rf values on silica gel-TLC and yields are:. A (72 mg) ; B (197 mg) ; C (47 mg) ; D (63 mg). Their antimutagenic activities in decreasing order are: B, D, C and A. That is, components B and A, phloroglucinol-derivatives of gallocatechin and catechin, respectively, had the lowest and highest RMA.
    3. Examination of the chemical structures and the antimutagenic activities of these polyphenolic products from kaki-tannin revealed that a pyrogallol ring, a benzene ring having three adjacent phenolic hydroxyl groups, was re-confirmed to be essential in antimutagenic activity. Furthermore, it was found that the component with a pyrogallol ring attached at the 2 position of the flavanol C ring is more active as the antimutagenic substance than that linked at the 3 position in a form of gallic acid ester.
    4. That expression of this activity was closely related to a system of DNA excision repair in Escherichia coli was implicated by using a mutant strain which lacked this particular repair system.
    The data presented here indicate that kaki-shibu contains at least two types of UV-antimutagenic substances, a tannin-related component and an unknown compound. Thus, the astringent kaki fruit may be a new source of physiologically active compounds.
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  • Tomoaki Matsuo, Saburo Itoo, Ruth Ben-Arie
    1991 Volume 60 Issue 2 Pages 437-442
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Japanese persimmon fruits, such as cvs. 'Hiratanenashi', 'Atago', and 'Yokono', have remarkable astringency even at a mature stage, so it is only edible after removal of the astringency. Postharvest treatments for removing astringency from astringent cultivars of persimmon fruits, without concomitant softening, include alcohol vapor, carbon dioxide, and warm water. The mechanism of such artificial de-astringency is still obscure.
    Two chemicals (0.1% dinitrophenol and 1.0% arsenic trioxide), which inhibit aerobic respiration, caused de-astringency in astringent persimmon fruits held in a normal atmosphere. The tissues which absorbed these chemicals showed no abnormal softening. These treatments induced accumulation of ethanol and acetaldehyde at high concentrations in the tissues. However, malonic acid (10 mM), which induced ethanol and acetaldehyde accumulation at lower levels, was not effective in removing astringency from the fruit.
    An experiment using heated fruit (75°C for 15 min) with a high quantity of soluble kakitannin showed that acetaldehyde reacted with kakitannin, causing it to be insolubilized in the fruits, but ethanol did not.
    We conclude that removal of astringency from persimmons is the result of a direct reaction between acetaldehyde, produced during anaerobic respiration, and soluble kakitannin, forming an insoluble, non-astringent product.
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  • Jamnong Uthaibutra, Hiroshi Gemma
    1991 Volume 60 Issue 2 Pages 443-448
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The changes in the content of endogenous abscisic acid, membrane permeability and anthocyanin content of 'Jonagold' apples (Malus domestica Borkh.) were examined during the pre- and post-harvest periods. The endogenous ABA content of both peel and pulp did not change appreciably and remained less than 30 ng. g-1 dry weight until 105 days after full bloom (DAFB). Thereafter, the ABA content tended to rise up through 160 DAFB parallelling the increase in anthocyanin content. After harvest, marked changes in fruit firmness, membrane permeability and ABA content were observed throughout the storage period. These results suggested that the presence of endogenous ABA is one of the factors which affect the maturation and senescence processes of the fruit.
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  • Hiroto Yoshioka, Koji Aoba, Masashi Fukumoto, Kunio Fujimoto
    1991 Volume 60 Issue 2 Pages 449-455
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The molecular weight of NADP-malic enzyme (ME) in apple fruit is about 270, 000 and the enzyme molecule seems to be a tetramer composed of the same 4 subunits. The enzyme shows absolute specificity for NADP+ and no detectable activity when NAD+ replaced NADP+ in the assay mixture. The enzyme also requires a divalent cation such as Mn++ and Mg++ for its activity. In the presence of Mn++, optimum pH for the reaction was 7.5. The Km values for malate and NADP+ were 1.0 mM and 20.8 μM, respectivly. In the presence of Mg++, the Km values for malate and NADP+ at optimum pH of 7.2 were 4.0 mM and 60 μM, respectively.
    The ME activity increased with ripening, concomitant with an increase in the amount of enzyme protein determined by the ELISA method. The rate of increase in enzyme activity with ripening seems to be highest in late maturing apple cultivars.
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  • Haruyuki Kuroda, Shonosuke Sagisaka, Minoru Asada, Kazuhiko Chiba
    1991 Volume 60 Issue 2 Pages 457-466
    Published: 1991
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Activities of NADH-Cyt c reductase and Cyt c oxidase, two enzymes involved in the electron-transport chain in plastids, mitochondria and microsomes in apple trees, Malus pumita Mill., were measured throughout the course of a year. In August, as growth and enlargement of twigs ceased, the activities of NADH-Cyt c reductase and Cyt c oxidase in organellar fractions of the living bark and flower buds began to rise. In the flower buds, the increase in the activities of the two enzymes in the mitochondrial and microsomal fractions continued until December. The levels of the two activities remained high during wintering and then the activities increased again in early April, prior to the onset of budding. In the plastid fraction the two activities continued to increase until mid-May. In the living bark, the two activities in the organellar fractions exhibited a tendency to decrease transiently in October; and thereafter they continued to increase until April. In the xylem, the activities of the two enzymes in the organellar fractions reached basal levels by late August or early September. Subsequently, the activity of NADH-Cyt c reductase did not change significantly during the winter, whereas that of Cyt c oxidase exhibited a transient increase from mid-December to early February. These changes in the living bark, xylem and flower buds were correlated with changes in the fine structures of these cells; microsomes, mitochondria and plastids in the wintering cells were more plentiful in midwinter than in summer. These results suggest that the increased activity of the electron-transport chain in winter participates not only in the metabolism required for wintering and growth in spring, but also results in an enhanced flow of electrons via the univalent pathway of reduction of oxygen that produces various species of active oxygen in the non-photosynthetic tissues.
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