Journal of the Japanese Society for Horticultural Science
Online ISSN : 1880-358X
Print ISSN : 0013-7626
ISSN-L : 0013-7626
Volume 71 , Issue 1
Showing 1-21 articles out of 21 articles from the selected issue
  • Doo Gyung Moon, Fusao Mizutani
    2002 Volume 71 Issue 1 Pages 1-7
    Published: January 15, 2002
    Released: January 31, 2008
    JOURNALS FREE ACCESS
    The effect of water stress on soluble solids content (SSC) and titratable acid content in different portions of fruit was examined in maturing 'Okitsu' satsuma mandarin (Citrus unshiu Marc.). In the control fruit, the difference in SSC in the radial direction became greater as the fruit matured. The difference in acidity became smaller with maturation in the stylar end in the radial direction and at the outer portion in the axial direction. Water stress caused a 12% to 47% increase in SSC in all fruit parts, compared with the control fruit from 140 to 230 days after anthesis (DAA) ; it especially affected the stem end. Water stress caused an 11-17% increase in acid content in the central portion of the equator, and a 4-13% reduction in the outer portions from 190 to 230 DAA. Thus, it seems that overall water stress induces and increase in SSC and an increase or decrease in acid content in different portions of fruit.
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  • Goro Okamoto, Yoshiko Hayashi, Ken Hirano
    2002 Volume 71 Issue 1 Pages 8-12
    Published: January 15, 2002
    Released: January 31, 2008
    JOURNALS FREE ACCESS
    The development of the transmitting tissue (TT) in pistils of diploid and tetraploid grapes was compared. Pre-bloom pistils of two diploid grapes, 'Campbell Early' and 'Muscat of Alexandria', and pistils of two tetraploid grapes, 'Kyoho' and 'Suiho', were cross-sectioned at intervals during 21 days before anthesis (DBA). In mid-style sections the TT size and the number of TT cells per style were similar between the diploid and tetraploid cultivars, although the initiation of the TT began earlier in diploid grapes than in the tetraploid ones. In the ovaries of the diploid grapes, 3 to 5 layers of the cells in the outer septa at the position of the upper ovules became round and loosely packed, considered to be converted into TT cells 13 DBA. Similar cells, consisting of only 1 or 2 layers of the septum in the tetraploid grapes, were converted to TT cells in 9 or 6 DBA, depending on the cultivar. Ovary growth and pollen development during the 2 weeks before anthesis, however, proceeded faster in the tetraploid grapes than in the diploid ones. We concluded that the insufficient TT development in tetraploid grape ovaries is caused by an inactive conversion of septum cells into TT between 13 and 6 DBA, when the florets are growing actively.
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  • Sojiro Chikaizumi
    2002 Volume 71 Issue 1 Pages 13-18
    Published: January 15, 2002
    Released: January 31, 2008
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    Experiments were carried out to clarify the causes of rind disorders in 'Ootani' iyo fruit. Rind disorders were observed at a maturing stage and during storage. The disorders were classified into three types, based on visible symptoms and causal factors. The first type occurs on the fruit surface only when the fruit on the tree are exposed to solar radiation and is designated as "sunscald". The causal factor seemed to be high temperature stress. The second type which occurs during storage at 5°C, is known as "Kohansho" by growers and shippers. The disorder is not conspicuous at harvest, but appears during storage where the fruit surface had been exposed to sunlight. The third type which is observed on the fruit exposed to -2°C during storage is called "Yakesho" which apparently differs from "Kohansho". The latter two types of disorders do not occur when the fruit are wrapped with polyethylene film bag after pretreatment at 20°C for two days. However, the rind disorders develop after the bag is removed. The exposure of harvested fruit to 50 ppm ethylene failed to prevent the disorders.
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  • Andre Freire Cruz, Takaaki Ishii, Isao Matsumoto, Kazuomi Kadoya
    2002 Volume 71 Issue 1 Pages 19-25
    Published: January 15, 2002
    Released: January 31, 2008
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    The distributions of vesicular-arbuscular mycorrhizal (VAM) hyphae in the rhizospheres of trifoliate orange (Poncirus trifoliata Raf.) and some plants grown under greenhouse conditions were explored. Furthermore, the effect of the 25% MeOH eluates of bahiagrass (Paspalum notatum Flugge.) and millet (Pennisetum glaucum L. R. Br.) roots fractionated by flash chromatography on the network establishment of VAM hyphae was examined. Special acrylic root boxes with three compartments separated by nylon screens were used for the experiment. Seedlings of trifoliate orange were transplanted into one outer compartment in all boxes, and seedlings of bahiagrass, millet, cockscomb (Celosia cristata L. cv. Parade), radish (Raphanus sativus L. cv. Natsumino), and tomato (Lycopersicon esculentum Mill. cv. Fukuju) were transplanted into the other outer compartment. A VAM fungus, Gigaspora margarita Becker and Hall, was inoculated in the center compartment. In plots with only trifoliate orange seedlings, 25% MeOH eluates of bahiagrass root extract (BRE) and millet root extract (MRE) were applied into the other outer compartment once a week. A plot with only trifoliate orange seedlings and without BRE and MRE applications was also prepared as a control. The density of hyphae, percentage of infection, and number of spores in the bahiagrass and millet compartments were higher than those in the compartments with trifoliate orange. These parameters in the cockscomb, radish and tomato compartments, however, were markedly low as compared with the trifoliate orange compartments. Although few VAM hyphae and spores were observed in the control (no plant compartment), the density of hyphae in the compartments treated with BRE and MRE increased to around 18%, and a few spores were found in these compartments. Root exudates of trifoliate orange, bahiagrass, and millet stimulated the hyphal growth of G. margarita in vitro. Particularly, the stimulation by bahiagrass and millet was significantly greater than that of the control (agar only). But the hyphal length of cockscomb, radish, and tomato treatments was shorter than that of the control. These results suggest that under field conditions, root exudates will affect the behaviour of VAM fungi in the soil. Moreover, some compounds in BRE and MRE may act as chemotropic signals for attracting VAM hyphae.
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  • Hisashi Kokubun, Toshio Ando, Shuji Kohyama, Hitoshi Watanabe, Tatsuya ...
    2002 Volume 71 Issue 1 Pages 26-39
    Published: January 15, 2002
    Released: January 31, 2008
    JOURNALS FREE ACCESS
    Petunia axillaris seedlings from 102 localities in Uruguay were examined for the range of morphological variations. When three floral characters and seven vegetative characters that are horticulturally important were measured, they varied significantly between the two subspecies axillaris and parodii, except for plant height and leaf length. Cluster analyses of variations of characters, relative to the population locality, revealed that plant height and width and number of lateral stems segregated into six growth forms : upright, medium, compact, lax, small prostrate, and large prostrate. These growth forms seemed to represent ecotypical groups rather than taxonomical. The relationship between the growth forms and the environment of native habitats are discussed. In addition, we noted the growth forms that have horticultural potentials and their application to breeding.
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  • A. F. M. Jamal Uddin, Fumio Hashimoto, Shinichi Nishimoto, Keiichi Shi ...
    2002 Volume 71 Issue 1 Pages 40-47
    Published: January 15, 2002
    Released: January 31, 2008
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    Floral flavonoid content in relation to petal color before and after anthesis in four cultivars of lisianthus [Eustoma grandiflorum (Raf.) Shinn.] were determined. 'Bridal Violet' and 'Asuka no Asa', 'Azuma no Yosooi', and 'Mickey Rose' were classified into delphinidin, pelargonidin, and cyanidin major types, respectively, from HPLC profiles ; peonidin and malvidin existed as minor components. Anthocyanin synthesis began before anthesis ; total anthocyanins tended to increase after anthesis. Whereas flavonol content reached its maximum before anthesis in all cultivars, as the lisianthus petals unfurled, other anthocyanidin(s) appeared, resulting in changes in anthocyanidin ratios. However, those ratios remained nearly constant after anthesis ; flower color did not change during flowering. With respect to pigment constitution, it was the first case that 'Mickey Rose' was found to be cyanidin dominant. Results on flavonol contents suggest that the copigment effect was not present in lisianthus cultivars.
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  • Akira Tateishi, Hiroaki Inoue, Shohei Yamaki
    2002 Volume 71 Issue 1 Pages 48-55
    Published: January 15, 2002
    Released: January 31, 2008
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    cDNA clone encoding a β-galactosidase, AV-GAL, was isolated from fruit of avocado (Persea americana Mill) in which both nucleotide and deduced amino acid sequences had about 70 % identity with those of other plant β-galactosidases. The calculated molecular mass of the presumptive protein, which consists of 766 amino acids, was 85.8 kDa. It contained a putative active site which contained a consensus sequence, G-G-P-[LIVM](2)-x(2)-Q-x-E-N-E-[FY] (amino acid 182-194), belonging to glycosyl hydrolase family 35 and a putative signal peptide which would be cleaved between cysteine and serine (amino acid 35-36). Southern hybridization revealed that avocado β-galactosidase constitutes a small gene family and the probe generated from the 3′-region of AV-GAL, AV-GAL-C, had a higher specificity. Northern blot analysis showed that the AV-GAL-C probe hybridized to a single 3.3 kb RNA. The steady-state level of β-galactosidase mRNA, which was initially detected in the fruit 4 days after harvest, decreased 3 days later. The accumulation of β-galactosidase mRNA temporally corresponded to fruit softening and detectable ethylene production. Moreover, the increase in mRNA accumulation with fruit ripening coincided with changes in the activity of AV-GAL III which is the β-galactosidase isoform most responsible for avocado fruit softening. These results suggest that AV-GAL might be the code for AV-GAL III.
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  • Doo Gyung Moon, Fusao Mizutani
    2002 Volume 71 Issue 1 Pages 56-58
    Published: January 15, 2002
    Released: January 31, 2008
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    The relationship between the ratios of the transverse diameter to the longitudinal (D/L ratio) and titratable acidity in the axial direction was determined at harvest in 14 citrus cultivars and species with different shapes : 'Nichinan No.1', 'Okitsu', 'Nankan No.20', 'Kuno', and 'Aoshima' satsuma mandarin (C. unshiu Marc.) ; 'Miyauchi' iyo (C. iyo hort. ex Tanaka) ; Amakusa ([{C. unshiu Marc.×C. sinensis Osbeck}×C. unshiu Marc.]×[{C. paradisi Macf.×C. reticulata Blanco}×C. clementina hort. ex Tanaka]) ; 'Yoshida' ponkan (C. reticulata Blanco) ; 'Shiranui' ([C. unshiu Marc.×C. sinensis Osbeck]×C. reticulata Blanco) ; 'Valencia' and 'Delta' orange (C. sinensis Osbeck) ; 'Marsh' grapefruit (C. paradisi Macf.) ; lemon (C. limon Burm. f.) ; Hebezu (C. sp.). The D/L ratio was positively correlated with the mid-section/stylar end ratio of acid content (r=0.76). It seems that the more depressed globular the fruit shape, the higher the acidity at the mid-section.
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  • Toshihiko Hiraya, Hiroko Shimizu, Kazuo Ichimura
    2002 Volume 71 Issue 1 Pages 59-61
    Published: January 15, 2002
    Released: January 31, 2008
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    Floret senescence of Oxypetalum caeruleum was investigated in relation to ethylene production and its sensitivity to ethylene. Ethylene production increased as the florets senesced, and conversely, their senescence was accelerated by exogenous application of ethylene at 2 or 10 μl·liter-1 for 24 hr, indicating that Oxypetalum florets are sensitive to the gaseous hormone. Treatment with silver thiosulphate complex (STS), an ethylene action inhibitor, extended the vase life of florets. Thus, ethylene is considered to be involved in the senescence of cut Oxypetalum florets.
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  • Shin Hiratsuka, Manabu Watanabe, Yoshitaka Kawai, Tsutomu Maejima, Kei ...
    2002 Volume 71 Issue 1 Pages 62-67
    Published: January 15, 2002
    Released: January 31, 2008
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    The mechanism of flower thinning by calcium formate was investigated in the Japanese pear cv. Kosui (Pyrus pyrifolia Nakai). Calcium formate thinned 30-40% flowers when a 1% solution was applied to the pistils just before or 24 hours after pollination, whereas 1% calcium acetate and calcium lactate were ineffective. Both adhesion of pollen grains to stigmatic surface and tube elongation in the style were reduced by calcium formate application. Calcium formate at 0.05% or higher concentrations was a much stronger inhibitor on pollen germination in vitro compared to calcium acetate or calcium lactate. When the inhibitory effect of formic acid, acetic acid, and lactic acid in vitro on pollen germination was compared, formic acid was the strongest inhibitor, suggesting that the compound induces floral abscission by preventing fertilization through the action of formate. At harvest, there was little or no difference in size and sugar content between the treated and control fruits. Thus, calcium formate may be a promising chemical thinner for Japanese pear flowers by reducing the cost of hand thinning.
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  • Masahiro Kawamata, Hitoshi Ohara, Katsuya Ohkawa, Yoshihiro Murata, Ei ...
    2002 Volume 71 Issue 1 Pages 68-73
    Published: January 15, 2002
    Released: January 31, 2008
    JOURNALS FREE ACCESS
    Four-year-old trees of fig (Ficus carica L. 'Masui Dauphine'), grown hydroponically in a greenhouse kept over 15°C, were supplied with a half Enshi solution (EC 1.5 dS·m-1). For the first cropping, the trees were headed back on January 10. The yield of fruits harvested from the primary shoots between June 7 and September 30 was about 1.5 kg or 15.0 fruits per the primary shoot ; the average fruit weighted 104 g and had a Brix of 14. For the second cropping, all shoots were pinched at their 30th nodes on June 14 ; half were headed back again to their 3rd nodes on July 26. The yield from the secondary shoots harvested from November 24 to February 14 of was 1.3 kg or 15.8 fruits per shoot, the average fruit weighted 80g and had a Brix of 16. The percentage of fruit set at the 12-20th nodes on the secondary shoots of the pinched tree was smaller than that on other nodes. However, fruits on the secondary shoots of the headed trees, which were harvested from December 24 to February 14, weighted 1.0 kg or 12.5 fruits per shoot ; the average fruit weighted 72 g and had a Brix of 16. Thus, we conclude that fig tree grown hydroponically could be forced to yield double crops of high quality fruit.
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  • Akira Tamura
    2002 Volume 71 Issue 1 Pages 74-81
    Published: January 15, 2002
    Released: January 31, 2008
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    The relationships between freezing tolerance of spinach (Spinacia oleracea L.) and komatsuna (Brassica campestris L.) plants and air temperature, water content, and sugar concentration were investigated in an unheated greenhouses from autumn to early spring in 1996-99. Freezing tolerance was expressed as the temperature at which 15% (TEL15) or 50% (TEL50) of electrolyte leakage from leaf blade tissues occurred. The TEL15 and TEL50 of spinach and komatsuna decreased gradually from October to January. In the coldest season, the TEL15 and TEL50 were decreased to -12--16°C and -13--18°C in spinach, and -12--14°C and -13--17°C in komatsuna, respectively. From mid-February, the TEL15 and TEL50 of spinach and komatsuna increased with a rise of air temperature. There was a high correlation between the freezing tolerance and the mean minimum air temperatures for 7 days before the measurement were made. The freezing tolerance of spinach and komatsuna increased only slightly when the mean minimum air temperature was between 8 and 2°C, but increased considerably when the temperature decreased below 2°C. The changes in the freezing tolerance of spinach and komatsuna also correlated with leaf water content. The freezing tolerance increased as the leaf sugar content increased from 10 to 20 mg·g-1 FW in spinach and from 10 to 35 mg·g-1 FW in komatsuna. Further increases in sugar content had no effect on freezing tolerance in both species.
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  • Kazuhiro Dan, Shigeo Imada
    2002 Volume 71 Issue 1 Pages 82-86
    Published: January 15, 2002
    Released: January 31, 2008
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    The total phenol and anthocyanin contents increased in leaves of cabbage seedlings growing under a 12-hr photoperiod at a PPFD of 160 μmol·m-2·sec-1 and 10/5°C (day/night). In the dark, low temperatures did not induce significant changes in total phenol and anthocyanin contents. When excised leaf discs of cabbage seedlings were incubated at low temperatures with aminooxyacetic acid, an inhibitor of phenylalanine ammonia-lyase, the total phenol contents in the chilled leaf discs decreased gradually in the light and dark. However, the thiobarbituric acid reactive substances (TBARS) content which reflects lipid peroxidation, increased significantly in the leaf discs chilled in the light, but not in the dark. These results suggest that phenolic compounds in leaves of cabbage seedlings have an important role for suppressing lipid peroxidation caused by low temperature and exposure to the light.
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  • Toshinari Kanazawa, Keisuke Terui, Ryuta Oikawa, Takuro Horaguchi, Koh ...
    2002 Volume 71 Issue 1 Pages 87-93
    Published: January 15, 2002
    Released: January 31, 2008
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    Seed germination and the subsequent development of male and female Chinese yam (Dioscorea opposita Thunb.) collected in China were investigated. The accessions may serve as a source of germplasm for future breeding. The optimum temperature for seed germination was 11°C in the dark. Leaves proliferated rapidly 40 days after planting and the shoots elongated until 60 days after planting in 1-, 2- and 3-yr-old seedlings. New shoots emerged from the old tuber which shriveled as it supplied the new developing tuber with nutrients. The male seedlings produced more leaves than did female ones during their second and third years of growth. Fifteen out of nineteen 2-yr-old seedlings initiated inflorescences ; seven bore male flowers, while eight differentiated female flowers. The female flowers developed seeds which matured as the three-lobed capsules turned brown. The number of globular or ellipsoidal bulbils which form in the leaf axils increased annually. Their fresh weight did not differ between male and female seedlings. The length, fresh weight, and diameter of the tubers increased annually during the three seasons ; the tubers on the male seedlings were consistently larger than those from the female ones.
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  • Masami Morishita, Keita Sugiyama, Takeo Saito, Yoshiteru Sakata
    2002 Volume 71 Issue 1 Pages 94-100
    Published: January 15, 2002
    Released: January 31, 2008
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    Using an improved method for evaluating powdery mildew (Sphaerotheca fuliginea) resistance for cucumber, our genetic resources were estimated for the breeding of resistant cucumber cultivar adaptive for greenhouse cultivation during winter to spring. The relationship between the resistance to the pathogen and the ambient temperature was analyzed by the spray inoculation of conidia suspension under controlled conditions. Although the cultivars, 'Asomidori-go-gou' and 'Natsufushinari' were resistant between 25 to 30°C, they became susceptible at 15 to 20°C. The nature of resistance was affected by the duration of the exposure to 30°C and 15°C during the day. To screen the resistant cultivars and lines independent on temperature, 295 cucumber accessions were inoculated at 20°C and 26°C. All accessions tested could be divided into three types on difference of resistance response to temperature. Seven accessions were classified as the type I for being resistant under both 26°C and 20°C ; 34 accessions were recognized as type II because they were resistant under 26°C ; the remainder belonged to type III, being susceptible at both 26°C and 20°C. Many of the resistant accessions were Chinese cultivars and lines. 'PI197088-5', a progeny of 'PI197088' which originized in India, possessed the highest level of resistance among all accessions. Thus the selection 'PI197088-5', whose resistance is temperature-independent is the most suitable parent for breeding of powdery mildew resistance in greenhouse-grown cucumber.
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  • Tatsuo Sato, Makoto Yoshida, Takeshi Oya
    2002 Volume 71 Issue 1 Pages 101-106
    Published: January 15, 2002
    Released: January 31, 2008
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    Pulse amplitude modulation (PAM) chlorophyll (Chl) fluorescence yield measurement was evaluated for estimating the high-temperature stress tolerance of vegetable crops. For this purpose, twenty two kinds of vegetable crops comprising of 17 taxonomic species were grown in controlled environments at the following three temperature regimes : (1) the air temperature during the 14-hr photo period was maintained at 20°C ; (2) it was raised stepwise at 5°C hr-1 from 20°C to 35°C, and then immediately decreased stepwise to 20°C, and (3) it was changed similarly to (2) except that the duration at 35°C was prolonged to 3 hr. At night the ambient air was cooled to 10°C in all three pretreatments. Following the pretreatments for 48 days, photosystem (PS) II Chl. fluorescence yields of leaf sections were determined by PAM before and during exposure of leaf sections to 45°C for up to 5 hr. Based on the heat sensitivity of PS II fluorescence yields, the vegetable crops tested were grouped into the following three classes : (A) crops with heat-tolerant PS II, (B) those with PS II sensitive to heat but capable of high-temperature acclimation, and (C) those with PS II sensitive to heat and incapable of high-temperature acclimation. These groupings coincide well with those based on the field performance of the crops at high temperatures. It is thus concluded that the Chl fluorescence yield measurement is a simple and reliable method for estimating the high-temperature stress tolerance of vegetable crops.
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  • Yoko Mine, Ryozo Sakiyama, Hitoshi Saka
    2002 Volume 71 Issue 1 Pages 107-113
    Published: January 15, 2002
    Released: January 31, 2008
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    Slow sand filtration (SSF) is one method for disinfecting nutrient solutions in a closed soilless culture system. Microbe removal efficiency of such filtration was evaluated by determining the definite inoculant microbe density of influents and filtrates. The well water was inoculated with a suspension culture of tomato bacterial wilt pathogen (Pseudomonas solanacearum) to a density of 1.2×103 cfu·ml-1 as an influent. When the inflow of this water to the sand filters kept at 30°C lasted for 32 hr, the bacterial density of filtrate began to increase 16 hr after the inflow started (HAS) and reached the maximum value of 2.2×102 cfu·ml-1 at 32 HAS. The time course of the density of filtrate was observed to have a plateau between 24 and 36 HAS. The mean value of 1.7×102 cfu·ml-1 during the period was employed as the definite density of filtrate. The filtrate/influent ratios revealed that the removal efficiency was 86% whereas it was 99% when the temperature of the sand filter was uncontrolled. The performance of SSF against the spread of tomato bacterial wilt was investigated in a NFT tomato growing system. When the system did not include SSF, the disease spread from two previously inoculated tomato plants to the rest of the 18 plants in the same bed within 25 days. The pathogen density of the nutrient solution kept increasing up to 107 cfu·ml-1 by the end of the culture. When SSF was installed into the NFT system, no wilting damage was observed unless plants were located downstream of the previously inoculated ones. The pathogen density of the solution, which passed through the rhizosphere of infected plants, increased up to 104 cfu·ml-1 and did not decrease throughout the experiment, although no pathogen was detected in the filtrates.
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  • Seiichi Fukai, Yoko Kamigaichi, Norimichi Yamasaki, Wei Zhang, Masanor ...
    2002 Volume 71 Issue 1 Pages 114-122
    Published: January 15, 2002
    Released: January 31, 2008
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    Dendranthema yoshinaganthum is an endemic species found along the Naka-river in Tokushima Prefecture, Japan. The habitat area has narrowed, compared to that reported in the 1950s. Thirty-six individuals of this species were collected from the habitat and from two institutes. There were considerable variations in leaf and flower morphology and flowering time among the specimen. Three lines with large plants obtained from two institutes were found to be octoploid (2n=72), whereas all others were tetraploid (2n=36). PCR-RFLP analysis of chloroplast DNA gene, trnK, showed that this species could be divided into two groups.
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  • Takashi Kubo, Genjiro Mori, Masayuki Oda, Masaaki Konagai
    2002 Volume 71 Issue 1 Pages 123-126
    Published: January 15, 2002
    Released: January 31, 2008
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    Shoot tips excised from the apical bud, axillary buds between the apical bud and the forth leaf (1st-4th leaf axillary bud) or axillary buds between the forth leaf and the eighth-leaf (5th-8th leaf axillary bud) were imbedded on MS medium containing 2 mg·liter-1 BA. Shoot tips excised from the apical bud developed a shoot and formed callus on the cut base, whereas those excised from axillary buds formed multiple shoots. The rate of multiple shoot formation from shoot tips of the 1st-4th leaf axillary buds was higher than that of the 5th-8th leaf axillary buds. The optimum concentration of BA in the medium for the maximum formation of multiple shoot was found to be 2 mg·liter-1 BA. The multiple shoots thus formed were proliferated efficiently by subculturing them on the medium containing 1 mg·liter-1 BA.
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  • Tomoaki Inoue
    2002 Volume 71 Issue 1 Pages 127-132
    Published: January 15, 2002
    Released: January 31, 2008
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    The effects of seed vernalization durations for 0, 10, 20, 30, 40 and 60 days at 1°C combined with subsequent 8-, 10-, 12-, 14-, 16- and 24-hr photoperiods at 15°C on the flowering time and the number of nodes to the first inflorescence of a summer, a spring and a winter flowering sweet pea were investigated. The first inflorescence of all flowering types occurred at the highest node and the number of days from sowing to first flower budding was longest in the 8-hr photoperiod with 0 day of seed vernalization. The number of nodes to the first inflorescence in this regime were 54.5, 43.8, and 27.8, respectively, for the summer, spring, and winter flowering types. After a 30-day vernalization, the first flower bud formation was promoted by 14 to 24-hr, 12 to 24-hr, and 8 to 24-hr photoperiods, respectively, for the summer, spring and winter flowering types. Plants of all flowering types produced their first inflorescence with the fewest nodes and shortest time under constant light and 60-day vernalization. The response to photoperid after a 60-day vernalization treatment was markedly smaller in the spring flowering type than in the summer flowering type, and did not exist in the winter flowering type. No statistical difference between the number of the first nodes to flowering and first inflorescence was observed among the seed vernalization treatments combined with the 16 to 24-hr, 12 to 24-hr, and 8 to 24-hr photoperiods, respectively, for the summer, spring and winter flowering types. After a few days of vernalization and short daylengths, the number of nodes to the first inflorescence was higher than the number of the first nodes to flower bud formed in the summer and spring flowering types on account of flower bud drop and vegetative bud formation. In conclusion, flowering of sweet pea seedling is markedly promoted by vernaling seeds for more than 30 days and exposing them to 16 to 24-hr, and 12 to 24-hr, and 8 to 24-hr photoperiods for summer, spring, and winter flowering types, respectively.
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  • Hidehiro Inagaki, Yoshinori Terada, Michiko Yamamoto, Hisao Otsuka, Yo ...
    2002 Volume 71 Issue 1 Pages 133-138
    Published: January 15, 2002
    Released: January 31, 2008
    JOURNALS FREE ACCESS
    Methods of promoting the germination of immature seeds in Lilium japonicum Thunb. at various stages of their development were investigated. 1. Although seeds and embryos reached their final sizes 2 months after pollination, they were immature but 80% of them germinated one month later. 2. The germination rate of immature seeds, harvested 3 months after pollination, then exposed to 30°C for 50 days, and then cooled to 15°C for 30 days were unaffected, whereas it increased one month later. 3. The germination rate of immature seeds, 3 months after pollination, improved significantly after 1) removing the seed coat ; 2) scarification ; 3) soaking in NaOH ; and 4) treatment with NaClO.
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