Journal of the Japanese Society for Horticultural Science
Online ISSN : 1880-358X
Print ISSN : 0013-7626
ISSN-L : 0013-7626
Volume 65 , Issue 3
Showing 1-27 articles out of 27 articles from the selected issue
  • Tatsuya Kubo, Vliyuki Maekawa, Shin Hiratsuka
    1996 Volume 65 Issue 3 Pages 447-453
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Assigning numerical values to rind roughness of satsuma mandarin as "roughness value" with an image analyzer, the changes in values during fruit growth were examined. The "roughness value" decreased gradually proportionately to fruit growth and development, but the rate of reduction depended significantly on crop load of the tress. In high crop load (leaf-fruit ratio; <10), the "roughness value" decreased continuously until harvest time, whereas it remained high in low crop laod (leaf-fruit ratio;>50). Significant differences in values between high and low crop load were observed during September and November.
    Juice sampled from July to December showed that the sugar concentration had a reverse sigmoid curve compared to the "roughness value" and that sucrose accumulation was especially repressed in the fruits with coarse surfaces. Similar tendencies were found among fruits on trees with a conventional crop load (leaf-fruit ratio ?? 25) at harvest.
    Rind roughness of satsuma mandarin fruit, thus, is closely reeated to sugar concentra-tion in pre-and mature fruits.
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  • Yoshitaka Kawai, Jason Benz, W. Mark Kliewer
    1996 Volume 65 Issue 3 Pages 455-461
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effect of different severities of root flooding at budbreak and 70 days after budbreak (8 to 12 leaf stage) on root and shoot growth of 'AXR#1', 'St. George', '11OR', and '420A' rootstocks was investigated. The four severities of root flooding were control (0%), 33%, 67%, and 100% of the root soil volume of each rootstock. At the budbreak stage, root and shoot growths of all rootstocks were strongly inhibited when two-thirds or more of the root soil volume was flooded. At 100% root flooding, there was no new root growth. The number of buds that sprouted and developed was unaffected by flooding. Within 10 to 15 days after flooding, the cuttings at 8 to 12 leaf stage of '420A' and '11OR' grew poorly. The color of roots exposed to 100% root flooding turned black in contrast to control plants which were mostly white. Flooding reduced the concentration of potassium and calcium in petioles of 'AXR#1' rootstocks markedly. Among the four rootstocks investigated, 'AXR #1' which was the most tolerant to flooding had the best shoot and root growths, followed by 'St. George', '110R' and'420 A'.
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  • Sunao Tachibana
    1996 Volume 65 Issue 3 Pages 463-470
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    In this experiment, effects of the planting density and various cultural treatments on fruit quality were determined using 'Miyagawa Wase', an early ripening satsuma mandarin. The planting densities were: 1, 250, 2, 500, 5, 000, and 10, 000 trees/ha. Additional treatments were: A, shallow plowing + limited fertilization with no pruning and no fruit thinning; B, shallow plowing + limited fertilization with pruning and fruit thinning; C, deep plowing + standard fertilization but no pruning and no fruit thinning; and D, deep plowing + standard fertilization with pruning and fruit thinning. Furthermore, the re-lationship between leaf area index (LAI) and fruit quality was also examined.
    The percentages of pulp weight, sugar content, sugar-acid ratio, and rind color in the shallow plowing + limited fertilization plot were higher than those obtained from the deep plowing + standard fertilization plot; the fruit quality in the pruning + fruit thinning plot was higher than that observed in the no pruning + no fruit thinning plot. The acid content was lower in the shallow plowing + limited fertilization plot than in the deep plowing + standard fertilization plot. The mean fruit weight was larger in the pruning + fruit thinning plot than in the no pruning + no fruit thinning plot.
    With the higher planting densities, the percentages of pulp weight, sugar content and acid content increased, but the sugar-acid ratio and rind color decreased.
    As for fruit quality, the acid content increased linearly with LAI, whereas the sugar-acid ratio decreased with increasing LAI. The rind color was acceptable and did not significantly change over a range of LAI from 1 to 5, but above LAI 5, it was poor.
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  • Sunao Tachibana, Shigeki Yahata
    1996 Volume 65 Issue 3 Pages 471-477
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    A differencial nitrogen fertilization trial for a high density planting of satsuma mandarin was conducted for 11 years. Starting in 1981, 12-year-old satsuma 'Sugiyama Unshiu' trees, which had been grown in a 0.4 ha field with little or no fertilizer were administered a combination of 2 levels of organic matter application and 3 levels of N replicated 3 times as a factorial design. Levels of organic matter were-OM (no organic matter application) and +OM (rice straw application of 20 t•ha-1•year-1).Levels of nitrogen fertilization were N-1 : 100, N-2 : 200, and N-3 : 300 kg-ha-lyear-1.
    The trees were spaced 2.2 m × 2.2 m, a quarter of the trees being designated as the permanent, another quarter of trees as the semipermanent, and the rest as fillers.
    1. The yield per hectare in all treatments increased significantly in the second year but then decreased slightly on account for bacterial canker attack ; the trees recovered and the yield increased rapidly but eventually leveled off with some yearly fluctuations.
    2. In the + OM treatment, the yield per hectare in the N-1 treatment was less than 10% of the N-2 and N-3 treatments, whereas in the OM treatment, the N-2 and N-3 treatments, the yields were 8% and 14% larger, respectively, than in the N-1 treatment. These results led to the conclusion that the amount of nitrogen fertilizer in a high density planting of satsuma mandarin can be reduced to 100 kg•ha-1•year-1 when 20 t•-1•year-1 of rice straw was annually applied or 200 kg•ha-1•year-1 when no organic matter was applied, without substantial crop reduction.
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  • Hiroo Mukai, Toshihiko Takagi, Youji Teshima, Tetsuo Suzuki
    1996 Volume 65 Issue 3 Pages 479-485
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Satsuma mandarin trees were water-stressed severely (WS-s) and moderately (WS-m) by withholding in autumn. Sugar contents of juice and peel were determined by HPLC.
    Sucrose and reducing sugars in the juice and peel were increased by the water stress treatment, notably, fructose in the peel.
    Increase of sucrose in the juice and peel was inhibited by WS-s. Total and reducing sugar concentrations in the peel from the WS-s plot were lower than those from the WS-m plot at harvest on November 26.
    Although the sugar content of the stylar end of the fruit was greater than that of the stem end, the % reducing sugars in the stem end was consistently higher than that of the stylar end. This relationship was not changed by water stress treatment.
    The peel color gradient from the stylar to the stem ends paralleled that of the sugar gradient; the gradient for titratable acidity was the reverse.
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  • Sunao Hisada, Takaya Moriguchi, Tetsushi Hidaka, Anna M. Koltunow, Tom ...
    1996 Volume 65 Issue 3 Pages 487-495
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Sequencing of randomly selected cDNA clones was carried out to survey the repertoire of genes expressed in immature seeds of 'Valencia' orange (Citrus sinensis Osbeck) and to produce restriciton fragment length polymorphism (RFLP) markers on the genome mapping program in Citrus. A cDNA library was made by using mRNA prepared from immature seeds of 'Valencia' orange whose developing embryos were at an early globular stage. A total of 192 individual cDNA clones were partially sequenced and compared with the GenBank database. The cDNA clones, which presented significant homology to previously characterized plant, eukaryote, and all other organism genes (optimized (OPT) score >200) in data source formed 24.5% (47 clones), 12.0% (23 clones) and 8.8% (17 clones) of total cDNA clones analyzed in this experiment. The seed cDNA library showed low level of redundancy of cDNA clones. Some clones such as metallothionein, however, were revealed several times, suggesting possible isoforms. Although putative genes, which are thought to play a role on embryogenesis, were not screened in this experiment, a wide range of genes involved in functions such as metabolism, translation, signal transduction, and stress responses were obtained. The randomly sequenced cDNA clones described in this study provide, for the first time, an indication of the types of genes expressed at an early stage of seed development in Citrus. Furthermore, this method made possible the selection of many gene species which could be used as RFLP probes.
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  • Toshiaki Motomura, Takaya Moriguchi, Tomoya Akihama, Tetsushi Hidaka, ...
    1996 Volume 65 Issue 3 Pages 497-503
    Published: 1996
    Released: May 15, 2008
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    Somatic hybrids were produced by protoplast fusion between embryogenic callus cells of 'Hazzara (Abohar)' (Citrus reticulata Blanco) and mesophyll cells of Microcitrus australis (Planch.) Swingle, in an attempt to expand genetic diversity that might be valuable for Citrus breeding. Among the 40 plants acclimatized, 37 plants were intermediate in leaf morphology, whereas, the remaining 3 had leaves quite different from those of both parents. Ten plants among those with intermediate leaf morphology were selected for analysis of genome composition. These plants proved to be somatic hybrids by nuclear rDNA analysis. Mitochondrial DNA (mtDNA) analysis showed that all 10 hybrids contained 'Hazzara (Abohar)' plastome. Analysis of chloroplast DNA (cpDNA) showed that most of them carried specific fragments derived from 'Hazzara (Abohar)'. Others, however, carried specific fragments derived from both parents. Possible causes for such band patterns are discussed from a genetical viewpoint.
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  • Toshihiko Sugiura, Hitoshi Honjo
    1996 Volume 65 Issue 3 Pages 505-512
    Published: 1996
    Released: May 15, 2008
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    To explain and predict the relation between weather and fruit growth in Japanese pear(Pyrus pyriforia Nakai, cv. Kosui), a model was constructed based on solar radiation and field growth data obtained from several regions in Japan. As a result of simulation, the following equation applicable to the estimation of the fruit growth under usual and unusual weather in every region was formulated.
    where Vx is estimated fruit volume at x days after flowering, V33 is observed fruit volume 33 days after flowering, kn is parameter indicating seasonal change in the influ-ence of Sd, Sd is observed daily solar radiation, p = 0.580 and b = 0.639. Transverse diameter of fruit at x days after flowering (wx) can be estimated from the following equa-tion.
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  • Mebelo Mataa, Shigeto Tominaga, Itaru Kozaki
    1996 Volume 65 Issue 3 Pages 513-523
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The annual partitioning dynamics of assimilated photosynthates in a low yielding ponkan (Citrus reticulata Blanco cv. Yoshida) and a high yielding cultivar, satsuma mandarin (Citrus unshiu Marc.) were compared. Starch, soluble sugars and hemicellulose in all above ground tissues were monitored at monthly intervals over a period of one year. Ponkan showed a continuous decrease of sugars and starch in all tissues except for mature wood from anthesis (May) until the end of fruit set period (July). Towards fruit maturity and approach of winter, there was a high accumulation of non-structural carbohydrates in the tissues. Maximum carbohydrate content in most tissues was reached in mid-winter (December to Januuary). A close relationship was found between non-structural carbohydrate accumulation patterns in the new leaves and shoots and fruit growth rate indicating that low sink strength of the developing ponkan fruit and inefficient mobilization of non-structural carbohydrates from the current season' s source leaves and mature wood caused low fruit set and yield in ponkan, in contrast to the satsuma mandarin fruit.
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  • Takaaki Ishii, Yogesh Hari Shrestha, Isao Matsumoto, Kazuomi Kadoya
    1996 Volume 65 Issue 3 Pages 525-529
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effect of ethylene on the growth of vesicular-arbuscular mycorrhizal (VAM) fungi and the VAM formation of trifoliate orange roots was investigated. Spore germination and hyphal growth of VAM fungi were stimulated at concentrations ranging from 0.01 to 0.1 ppm ethylene. At 0.2 ppm and above, however, hyphal growth was severely inhibited. The rapid hyphal growth noted at 0.07 ppm ethylene treatment was severely retarded by ethylene absorbents. VAM development in trifoliate orange trees was markedly enhanced at 0.05 ppm ethylene, but was depressed at 1 ppm. At 0.05 ppm, tree growth was vigorous and leaf P content was high. Thus we propose that very low levels of ethylene play an important role in the hyphal growth of VAM fungi and in the infection and spread of the mycorrhizae.
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  • Masayuki Oda, Masayasu Nagata, Kenkou Tsuji, Hidekazu Sasaki
    1996 Volume 65 Issue 3 Pages 531-536
    Published: 1996
    Released: May 15, 2008
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    Control of growth, fruit yield and sugar content of fruits were studied by comparing between tomato plants grafted on rootstocks of tomato (Lycopersicon esculentum Mill.) and scarlet eggplant (Solanum integrifolium Poir.). Vegetative growth tended to be depressed and the incidence of blossom end rot of fruits to be increased by grafting on scarlet egg-plant rootstocks. Fruit yield on scarlet eggplant rootstocks was lower than that on tomato rootstocks. Guttation was not observed in plants grafted on scarlet eggplant rootstocks. However, concentrations of leaf chlorophyll and the soluble solids and sugar contents in fruits were all higher in plants grafted on scarlet eggplant than on tomato rootstocks. These results indicate that plants grafted on scarlet eggplant rootstocks are likely in a state of water deficiency.
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  • Koichi Inoue, Kazuaki Sugimoto, Satoru Kondo, Yasuyoshi Hayata, Hirosh ...
    1996 Volume 65 Issue 3 Pages 537-543
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effects of administering a high concentration of sodium ascorbate (NaAs) and L-ascorbic acid to leaf lettuce roots for 16 hr prior to harvest on the foliar L-ascorbic acid (AsA) content were studied. Dipping roots in 2000 ppm NaAs or AsA caused the outer leaves of the plant to wilt. The foliar AsA content in the AsA treatments was remarkably greater than that in the NaAs treatments and was 4.5, 6.1 and 7.7 times greater in the 1000, 1500 and 2000 ppm treatments, respectively, in comparison with that of the control (21.5 mg/100 g FW).
    Immersing roots of Welsh onions and leaf lettuce for 12 hr in 1500 ppm AsA solution gradually reduced the rate of water absorption. Consequently, the fresh weight of plants treated for 12 hr decreased about 10%. However, this decrease was recovered by transferring the roots to disillued water at 15°C for 6 hr in the dark. The foliar AsA contents in the welsh onion and lettuce plants were 112.9 and 94.3 mg/100 g FW, respectively. The foliar AsA content in both plants increased linearly with time, while the increase of dehydro-ascorbic acid level was negligible.
    The results indicate that the AsA treatment was more effective than the NaAs treatment for AsA-rich leafy vegetables. Furthermore, we can ensure the approximate foliar AsA content after immersing the roots for a certain time period under a specific condition because the uptake rate per hr was almost constant.
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  • Nobuyuki Fukuoka, Hiroshi Yoshioka, Emiko Shimizu, Takahiro Fujiwara
    1996 Volume 65 Issue 3 Pages 545-551
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Cabbage seedlings were shaded to see what effects the treatment had on photosynthesis, root respiration, carbohydrate content, invertase activity, and their rooting ability after being transplanted into the nursery. The effects of irrigating shaded plants with a sugar solution on root respiration and rooting ability were also investigated.
    1. The rate of photosynthesis and root respiration declined in shade plants. Seedling had less carbohydrate in the top and roots as compared with those exposed to light.
    2. In plants transferred to shading plot, root respiration decreases rapidly, but the decline in invertase activity lagged behind that of root respiration.
    3. Lowered respiration activity in roots caused by the shade treatment was restored by irrigating with a sucrose solution; plants treated with sucrose solution had deeper and larger root distribution than did those in the -ucrose plot.
    From these results, we conclude that rooting ability after transplanting cabbage seedling to a nursery depends largely on carbohydrate content in the roots during the seedling stage. If nursery plants are subjected to low light intensity conditions, carbohydrate levels in the roots decrease because of lower photosynthetic activity. This decreased carbohydrate content causes a decrease in activity of those enzymes associated with respiration. Diminished photosynthates and lowered enzyme activities inhibit roots respiration. Consequently, a larger amount of energy is consumed for basal metabolism for survival which detracts from root formation after planting.
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  • Teruo Wada, Hideo Ikeda, Masafumi Ikeda, Hajime Furukawa
    1996 Volume 65 Issue 3 Pages 553-558
    Published: 1996
    Released: May 15, 2008
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    The reduction on the incidence of blossom-end rot (BER) of tomato fruits by foliar applications of a) plant extract (PE) containing an organic chelating agent; b) PE chemically combined with Ca (PE-Ca); c) PE-Ca mixed with sugar ester (PE-Ca+SE); d) PE-Ca+Fe; e) PE-Ca+Zn; f) PE-Ca+xylose; g) calcium chloride, and h) calcium nitrate was studied. The tomato plants were grown in a rockwool system.
    1. The foliar application of PE-Ca+SE and PE-Ca+Zn significantly reduced the incidence of BER as compared with the control. These treatments increased the marketable yield significantly and did not decrease the fruit quality. Thus, the foliar application of Ca solution containing SE or Zn was recommended to reduce the BER incidence of tomato fruits.
    2. Ca concentration of young fruits decreased quickly as the fruit grew, attaining the minimum value when the fresh weight became about 20 g, at which time the symptoms of BER began to appear. Compared with the normal fruits, BER fruits had considerably lower Ca concentration. A clear relationship between the BER incidence and the K/Ca ratio of young fruits or foliar Ca concentration was not botained.
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  • Fuminori Komai, Ichiro Okuse, Takashi Harada
    1996 Volume 65 Issue 3 Pages 559-564
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    To establish a plant-regenerating system through frequent somatic embryogenesis, a detailed investigation was undertaken on the effects of kinds, concentrations, and combinations of growth regulators on callus and somatic embryo formation from spinach root segments. Although no somatic embryogenesis occurred on the culture medium containing auxins alone, a low frequency of somatic embryo formation was shown on culture media containing auxins combined with natural cytokinins, namely 10 μM NAA with 10 μM zeatin, 30 μM NAA with 10 μM 2-iP, and 1μM 2.4-D with 0.1 μM zeatin or 10μM 2-iP. Somatic embryos also formed on culture madia containing auxins combined with GA3. From 50 to 70% of the root segment differentiated somatic embryos on culture media containing 10 to 30 μM NAA combined with 1 to 100 μM GA3. These results show that spinach somatic embryogenesis is most facilitated by NAA combined with GA3.
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  • Yoh-ichi Matsubara, Takashi Harada
    1996 Volume 65 Issue 3 Pages 565-570
    Published: 1996
    Released: May 15, 2008
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    Effect of constant and diurnally fluctuating temperatures on arbuscular mycorrhizal (AM) fungi [Glomus etunicatum (GE) and Gigaspora margarita (GM)] infection and the promotion of infected seedling growth through asparagus-AM fungus symbiosis were investigated.
    1. At constant temperatures, spore germination rate became maximum at 25°C in GE, and at 25°C and 30°C in GM. Hyphal growth was enhanced at 20°, 25 °C and 30 °C in GE, and at 25°, 30 ° and 35 °C in GM.
    2. Under constant bed soil of 20 °, 25 ° and 30 °C for 8 weeks after inoculation, there was no growth enhancement at 20 °C regardless of the AM fungus species; whereas at 25 °and 30 °C, the GE-and GM-inoculated plants were taller than the noninoculated plants. At 30 °C, the GM-inoculated plants were taller than those inoculated with GE. At 25 °C, the GE-or GM-inoculated plants had the most shoots and storage roots than did those at other temperatures. The rate of AM fungus-infected portions in a whole root system (as percentage of the total portions infected with AM fungus in a whole root system) was maximum at 25 °C in GE-inoculated plants but at 25 ° and 30 °C in GM-inoculated ones.
    3. Under the bed soil temperature conditions diurnally fluctuating in the range of 25 °C to 15 °C and 30 °C to 18 °C, 8 weeks after inoculation, the plants were taller and had more numerous shoots and storage roots in GE-inoculated plants than in GM-inoculated ones in a regime between 25 °C and 15 °C; the reverse was noted in a regime between 30 °C and 18 °C. Little difference in the rate of AM fungus-infected portions in a whole root system was recognized between the two temperature regimes in GE-inoculated plants, whereas in GM-inoculated ones, the rate became higher at the temperature fluctuated between 30 °C and 18 °C than it did at the temperature fluctuated between 25 °C and 15 °C.
    Consequently, it seems that in asparagus, the optimum temperature range for infection and the plant grwth enhancement through symbiosis differed between Glomus etunicatum and Gigaspora margarita.
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  • Masaharu Masudal, Hiroshi Hasegawa, Motofumi Nomura
    1996 Volume 65 Issue 3 Pages 571-577
    Published: 1996
    Released: May 15, 2008
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    Diurnal translocation of nitrogen and calcium absorbed by tomato roots was investigated in plants at the first two fruiting truss stages.
    1. The amount of nitrogen(15N) in the peduncle, calyx, and fruit was several timeshigher during the day than it was at night in both trusses. The incorporation of nitrogeninto fruits was proportional to their fresh weight. With respect to the form of nitrogen, ammonium-N was assimilated faster than nitrate-N during the day; this difference diminished at night. The differences in the incorporation rates between the two nitrogen forms increased with an increase in fruit weight.
    2. The import of calcium(45Ca) in the peduncle, calyx, and fruits was higher at night than during the day in both trusses. The activity of 45Ca in fruit of similar fresh weight was also higher at night than during the day.
    Although the xylem water potential and the mass flow driven by the transpiration force are important for the transportion of minerals, we attribute the fa3ster calcium import into fruits at night to positive root pressure, whereas nitrogen transport during the day occurred mainly through the xylem, and re-translocated from the leaves to the fruits through the phloem, as an assimilated organic nitrogen.
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  • Yuichi Uno, Michio Kanechi, Noboru Inagaki, Mayumi Sugimoto, Susumu Ma ...
    1996 Volume 65 Issue 3 Pages 579-585
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The value of sea aster, a wild halophyte species, as an agricultural genetic resource was demonstrated by comparing the effects of salt stess on seed germination and vegetative growth with two salt-tolerant vegetables, asparagus and table beet. Germination percentages of asparagus and table beet were about 90% in control, but, decreased respectively to 50% and 61% in 50 mM NaCl, and to 12% and 21% in 100 mM NaCl. In sea aster, seed germination was suppressed with increasing NaCl concentration to more than 50% of the control in 150 mM NaCl, indicating that the seeds are salt-tolerant at the germination stage. Asparagus and table beet seedlings were withered and killed by sudden exposure to 50 and 100 mM NaCl. In asparagus and table beet plants salt-stressed gradually and sea aster suddenly exposed to the final concentrations of NaCl in hydroponics, plant height was not significantly inhibited, but root length in salt-stressed plants elongated significantly compared with the controls in all three species. In asparagus and table beet, dry matter gain of roots seemed to be inhibited at 100 mM NaCl, whereas that of the sea aster at 150 mM NaCl was equal to the control; at 300 mM NaCl, dry weight gain was inhibited.
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  • Zhijun Li, Masayuki Oda, Kunihiko Okada, Hidekazu Sasaki
    1996 Volume 65 Issue 3 Pages 587-594
    Published: 1996
    Released: May 15, 2008
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    Effects of water stress and exogenous abscisic acid (ABA) treatments on thermotolerance of photosynthetic apparatus (PA) in cucumber (Cucumis sativus L.) leaves were investigated. Evaluation of thermotolerance was based on the heat sensitivity of photosystem II (PSII) based on chlorophyll fluorescence emission. Plants were water-stressed by either withholding water to intact plants or placing excised shoots in an open atmosphere in a glasshouse. The extent of water stress was monitored by measuring the water potential of leaves. At intervals during water stress treatment, the ratio of variable to maximum fluorescence (Fv/Fm) of leaves was determined. Immediately after that, the leaves were dipped in a water bath held at 45°C for 10 min and Fv/Fm values were determined again. Percentages of Fv/Fm values remaining after the heat treatment were used as a measure of thermotolerance of PA. With intact plants, thermotolerance of PA increased significantly when the leaf water potential was decreased to -1.0 MPa; it attained maximum at -1.5 to -2.0 MPa. However, the thermotolerance decreased when water potential was further lowered to -4.0 MPa. Leaves of excised shoots showed similar changes in thermotolerance of PA in response to the decrease in water potential, except that the maximum tolerance was obtained at -0.8 MPa. When intact plants were reirrigated after 3 days of water stress treatment, the thermotolerance of PA increased temporarily during the first 2 hr, and then decreased sharply within 24 hr to the level of the irrigated control plant leaves. Exogenous ABA applied to leaves of irrigated plants caused an increase in thermotolerance of PA depending on its concentrations. Leaves tre-ated with 1.00 mM ABA showed nearly complete tolerance of PA within a day; this high tolerance level was maintained for at least 6 days. Leaves treated with 0.01 to 0.25 mM ABA reached a peak tolerance after a day and then lost much of the ABA-induced thermotolerance after 3 days. The results indicate that the enhanced thermotolerance of PA in water-stressed cucumber leaves was probably mediated through a water-stress-induced increase in endogenous levels of ABA.
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  • Andre Gosselin, Hui-lian Xu, Mohammed Dafiri
    1996 Volume 65 Issue 3 Pages 595-601
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The purpose of this study is to determine an optimal source-sink relationship by pruning clusters to an appropriate size to maximize fruit yield of tomato plants grown under supplemental lighting (SL). An increase in SL from 50 to 150 μmol•-2•s-1 resulted in an increase in total fruit yield and percentage of marketable fruit. Large cluster size decreased percentage of marketable fruit. A SL of 150 μmol•-2•s-1 with fruit thinning prevented the reduction in marketable fruit yield. Using a SL of 150 μmlo•m-2•s-1 increased photosynthesis and sugars and starch centent in leaf. Fruit thinning caused an increase in glucose, fructose, and starch content in leaf but a reduction in photosynthetic rate. A large cluster size, representing a high photosynthate demand, decreased sugars and starch content and increased photosynthetic rate. The combination of a SL of 150 μmol•m-2•s-1 with 3 fruit/cluster appears to be a better source-sink equilibrium during periods of low natural light.
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  • Kazuhiro Dan, Masayasu Nagata, Ichiji Yamashita
    1996 Volume 65 Issue 3 Pages 603-608
    Published: 1996
    Released: May 15, 2008
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    The relationship between senescence of cotyledon of Japanese radish and changes in levels of antioxidants was investigated by monitoring the levels of malondialdehyde (MDA), chlorophyll (Chl), ascorbic acid (AsA), α-tocopherol (α-Toc) in cotyledons, and the percentage of electrolyte leakage from cotyledonary discs. The content of MDA, which reflects lipid peroxidation, increased 3 days after sowing paralleling the increase in electrolyte leakage and Chl loss. α-Toc content increased linearly 2 to 10 days after sowing, whereas the AsA content increased rapidly, reaching a maximum 3 days after sowing and decreasing thereafter. An increase in MDA was accompanied by a concomitant decrease in AsA content. The AsA content increased significantly when the cotyledonary discs were administered L-galactono-1, 4-lactone, an immediate precursor of AsA, which suppressed changes in MDA and Chl contents. These results suggest that AsA has an important role for suppression of lipid peroxidation and Chl loss in cotyledons of Japanese radish.
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  • Takuya Fujimoto, Hiroshi Yamagishi
    1996 Volume 65 Issue 3 Pages 609-614
    Published: 1996
    Released: May 15, 2008
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    RAPD (random amplified polymorphic DNA) analysis was applied to strains of 'Sugukina' and turnip varieties (Brassica campestris L.), to clarify the phylogenetic relationship between the two. 'Sugukina' is cultivated traditionally in Kyoto district. DNA fragment patterns of the nine 'Sugukina' strains and the twelve turnip varieties were compared and their relationships were estimated by cluster analysis.
    Total DNA was isolated from a leaf of each of the twelve plantlets of the respective strains and varieties, and used as a template of the polymerase chain reactions (PCR). For the PCRs, four kinds of decamer primers were used. Sixty-nine DNA fragments showed the definitive polymorphisms among the 252 plants analyzed, of which 50 bands were selected for comparison. More than 50% of the plants in at least one strain or variety possessed the 50 bands, whereas less than 50% of the plants in another strain or variety had the same bands.
    Similarity ratios of the DNA fragment patterns of each 'Sugukina' strain with the other eight strains ranged from 0.40 to 0.56, the average being 0.49. On the other hand, the average similarity ratio value of the 'Sugukina' with the turnip varieties was 0.30. By cluster analysis, all nine 'Sugukina' strains formed a cluster clearly isolating them from another cluster containing all the turnip varieties. In the cluster of the 'Sugukina', seven out of the nine strains were included in two subclusters, but the other two strains possessed the different positions from them.
    These results indicate that the 'Sugukina' is a unique group of vegetables, containing large genetic variations and having different genetic characteristics from the turnip varieties growing in Japan.
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  • Tadashi Takeda
    1996 Volume 65 Issue 3 Pages 615-623
    Published: 1996
    Released: May 15, 2008
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    Seed-propagated annual dianthuses, D. ×Mikadonadeshiko, D. barbatus, D. superbus var. longicalicinus, and D. japonicus, are grown for cut flowers in Japan. Investigations on the flowering behavior in responses to chilling and to day length in these dianthuses were carried out.
    D. ×Mikadonadeshiko and D. barbatus have a cold requirement for flowering as their representative cultivars Miss Biwako and Kurokawawase, and required exposure to natural chilling till mid-December for flower bud formation and stem elongation. Plants grown above 14°C remained vegetative, exhibiting no vernalizing effect.
    Long day length (LD) promoted flowering and stem elongation for the suboptimally or optimally vernalized plants, LD had no effect on flower bud initiation in non-vernalized plants. Nonvernalized plants initiated flower buds under natural short days during the winter.
    On the other hand, D. superbus var. longicalicinus and D. japonicus showed no cold requirement and were day neutral for flowering. Rosetted growth in winter was caused simply by low temperature which regresses stem elongation.
    Dianthus spp. which require low temperature possess a juvenile phase lasting 9 weeks from seeding by which time 9 to 10 leaf pairs are produced on the main stem. Seed ver-nalization was ineffective for these cultivars.
    In the youngest plants capable of being stimulated by low temperature, only the main stem bolted; the lateral shoots which were immature during vernalization remained vegetative even after vernalization. This demonstrated that the action of cold on flowering was limited to mature shoots.
    The differences in cold requirement among the six D. barbatus cultivars was also observed. The ever-flowering cv Kyakko required no chilling, whereas others, such as cv Arima, required 9 or more weeks of chilling at 5°C to flower.
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  • Hitoshi Watanabe, Toshio Ando, Shin-ichi Iida, Akihiko Suzuki, Ken-ich ...
    1996 Volume 65 Issue 3 Pages 625-634
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    To obtain information about the breeding of garden petunias for future reference, we crossed six cultivars of petunias and their historical seed parent (Petunia axillaris subsp. axillaris) with 41 native taxa of Petunia sensu Jussieu. The existence of two groups of the native taxa differing in their chromosome numbers (2n=14 and 18) was confirmed. Petunia cultivars (2n=14) and P. axillaris subsp. axillaris (2n=14) failed to set capsules when crossed with the taxa having a chromosome number of 2n=18. In contrast, hybri-dizations were possible when they were crossed with taxa of 2n= 14, except for P. integrifolia subsp. occidentalis.
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  • Toyomasa Anan, Hidekazu Ito, Shinji Monma
    1996 Volume 65 Issue 3 Pages 635-644
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Sugars, organic acids, amino acids, and vitamin C contents in the fruits of transgenic tomato carrying the TMV coat protein gene, nontransgenic tomato, cultivated species of tomato and their wild relatives were measured. The levels of vitamin B2, dietary fiber, and glutathione in the fruits of transgenic tomato and nontransgenic tomato were also compared.
    1. The results showed no significant differences in these chemical components between the fruits of transgenic and nontransgenic tomatoes. L. peruvianum and L. hirsutumhad much high concentrations of sucrose then the other species. The vitamin C and aspartic acid contents in fruits of transgenic tomato, the nontransgenic tomato and L. peruvianum were considerably higher than they were in the other species, whereas the γ-aminobutyric acid content was comparatively lower. L. cheesmanii had considerably higher glutamic acid, asparagine, and glutamine content than the other species had.
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  • Masaru Tanabe, Xu Wei Ma, Keishi Shimokawa
    1996 Volume 65 Issue 3 Pages 645-649
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    Ethylene-enhanced chlorophyll degradation in the peel of Satauma mandarin (Citrus unshiu. Marc.) was surveyed with a chromometer. Color values (L, a, b) were measured and the degreening status expressed as (L+b)/2+a.
    The ethylene-enhanced chlorophyll degradation was significantly inhibited by p-chloromercuribenzoate (PCMB), ethylenediaminetetraacetate (EDTA) 2, 2'-bipyridyl, 1, 10-phenanthroline, bathophenanthroline disulfonic acid, Tiron, KCN, hydroquinone, but not by sodium L-ascorbate, histidine, dithiothreitol, NaN3, 2, 5-dimethylfuran, and diethyldithiocarbamate (DIECA).
    The possible in vivo participation of chlorophyllase and Fe2+ (Fe3+) and O2(O2-) requiring enzymes as a key system in the chlorophyll degradation procese is discussed.
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  • Narongchai Pipattanawong, Nobuaki Fujishige, Kenji Yamane, Ryosuke Oga ...
    1996 Volume 65 Issue 3 Pages 651-654
    Published: 1996
    Released: May 15, 2008
    JOURNALS FREE ACCESS
    The effects of brassinosteroid on growth parameters of two day-neutral strawberries (Fragaria × ananassa Duch. 'Miyoshi' and 'Enrai') grown in a greenhouse were investigated. In both cultivars, brassinosteroid increased total leaf areas by 150-180% and the number of leaves, petiole length, and number of crowns by 110-140% over the untreated control plants. Runner formation was unaffected by the brassinosteroid. Dry weights of leaves, petioles, crowns, and total organs of plants treated with brassinosteroid were heavier than those of untreated plants, whereas the dry weights of roots from treated plants were equally heavy as those of the control. Brassinosteroid significantly increased the total number of flowers and number of inflorescences per plant, but not the number of flowers per inflorescence. Brassinosteroid significantly increased total marketable berries and total yield per plant in 'Miyoshi', but it did not increase yields of 'Enrai'.
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