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Volume 69, Issue 1
Displaying 1-21 of 21 articles from this issue
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Kazuyuki Abe, Kazuo Kotobuki, Toshihiro Saito, Osamu Terai2000 Volume 69 Issue 1 Pages 1-8
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSThe inheritance of resistance to pear scab, Venturia nashicola by European pear cultivars, was examined using intra-and interspecific hybrid. The seedlings were inoculated with a conidial suspension and the resistance to scab was rated as : highly resistant (HR), susceptible (S), or necrotic (N). All seedlings derived from selfing of susceptible Japanese pear cvs., 'Hosui' and 'Chojuro', were S ; whereas all selfed seedlings of European pear cvs. were HR, indicating that the European pear possesses a single dominant gene pair, VnVn, that controls high resistance to V. nashicola. To identify the resistant genotype of the European pear, the segregation of the resistance was examined by using test cross progenies obtained from 'Chojuro' (S) × interspecific hybrids, which were produced by 'Hosui' × 'La France' or 'Hosui' × 'Bartlett'. HR, S, and N seedlings were observed in populations of both progenies. However, the percentages of HR seedlings ranged from 40 to 60 in most progeny groups, indicating that 'La France' and 'Bartlett' possess the Vn gene in a homozygous condition. The occurrence of N seedlings suggested that the genetic factor(s) controlling the N phenotype is present in addition to the Vn gene in these cvs. Based on the following hypotheses (1) a single dominant homozygous gene controls the N phenotype, (2) a single dominant heterozygous gene controls the N phenotype, or (3) polygenes control the N phenotype, we tested segregations of scab resistance in 42 test cross progenies. Most of the progenies did not fit either 2HR : 1N : 1S or 1HR : 1S ratio. On the other hand, 39 progenies gave a good fit to a 1 HR : 1(N+S), suggesting that the N phenotype is under polygenic control. We concluded that European pears possess a single dominant gene pair, VnVn, to control high resistance to pear scab. 'La France' and 'Bartlett' are considered to possess polygenes that control necrotic phenotype in the absence of the Vn gene. The breeding of Japanese pears for multiple disease resistance by using European pears is briefly discussed.View full abstractDownload PDF (881K) -
Takaaki Ishii, Jiro Aikawa, Naoki Nakamura, Kazuo Sano, Isao Matsumoto ...2000 Volume 69 Issue 1 Pages 9-14
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSThe effect of citrus juice pomace extracts on in vitro hyphal growth of vesicular-arbuscular mycorrhizal (VAM) fungi and the mycorrhizal formation on trifoliate orange (Poncirus trifoliata Raf.) seedlings and Citrus iyo Tanaka trees was investigated. One hundred μl [equivalent to 6.5 g dry weight (DW) of satsuma mandarin (Citrus unshiu Marc.) and 4.3 gDW of Citrus hassaku Tanaka] of the 25% MeOH eluates of citrus juice pomace extracts significantly increased in vitro hyphal growth of Gigaspora ramisporophora Spain, but a 100% MeOH eluates inhibited it. In a plot where the solution consisting of 25% MeOH eluates of satsuma mandarin juice pomace extracts (equivalent to 10 gDW) and liquid fertilizers was applied to the soil inoculated with the spores of Gigaspora ramisporophora, the percentage of VAM infection in trifoliate orange roots was six times higher than that in the control (water only) after one week. When the above mixed solution was administered to a Citrus iyo orchard via a sprinkler irrigation system, VAM development was markedly stimulated as compared to the untreated plots (liquid fertilizer only) and the control (solid fertilizer only). These results show that 25% MeOH eluates of citrus juice pomace extracts contain stimulatory substances for VAM fungi. Furthermore, the application of the 25% MeOH eluates to the soil is very effective in stimulating VAM development.View full abstractDownload PDF (782K) -
Yasuo Suzuki, Katsuhiro Shiratake, Shohei Yamaki2000 Volume 69 Issue 1 Pages 15-21
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSVacuolar H+-ATPase (V-ATPase) and vacuolar H+-inorganic pyrophosphatase (V-PPase) generate an electrochemical gradient across the vacuolar membrane, which is indispensable for accumulating sugars into the vacuole. We investigated the enzymatic and transcriptional changes of V-ATPase and V-PPase in Japanese pear fruit to establish their roles in fruit development. As fruit developed, the V-ATPase and V-PPase activities increased on the total protein basis. The V-PPase activity was higher than that of V-ATPase throughout the developmental period. Immunoblot analyses indicated that the changes in the polypeptides for the catalytic subunit of V-ATPase and V-PPase generally paralleled the enzymatic activities. Furthermore, seasonal changes in the mRNA levels generally corresponded with those of polypeptides except at the cell division stage. Our findings suggest that V-PPase, more than V-ATPase, plays an important role throughout the development of Japanese pear fruit and that V-ATPase and V-PPase are regulated at the transcriptional level during the cell elongation stage.View full abstractDownload PDF (948K) -
Mayumi Befu, Akira Kitajima, Xiao Ling Yang, Kojiro Hasegawa2000 Volume 69 Issue 1 Pages 22-28
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSChromosome samples of young leaves of 'Tosa-Buntan' pummelo (Citrus grandis [L.] Osb.), 'Washington' navel orange (C. sinensis [L.] Osb.) and trifoliate orange (Poncirus trifoliata [L.] Raf.) were prepared by the enzymatic maceration method. The preparations were sequentially stained with Giemsa, quinacrine mustard (QM), chromomycin A3 (CMA), and 4'-6-diamidino-2-phenylindole (DAPI). The chromosome lengths and banding patterns among 4 staining methods were compared. The discrimination of centromeres was easier by QM staining than by Giemsa staining. By CMA staining, 5 characteristic banding patterns were observed. Therefore, 'Washington' chromosomes were divided into 4 groups, trifoliate orange chromosomes into 3 groups, and 'Tosa-Buntan' chromosomes into 5 groups. CMA staining enabled the confirmation of chromosome number as 18 in cells in which chromosome lengths were relatively long. Chromosome number in 'Washington' and 'Tosa-Buntan' were difficult to count by the Giemsa stain. We conclude that chromosome samples prepared by using young leaves and QM and CMA stainings are effective means to reveal chromosomes in citrus. Hence, a good possibility of karyotyping citrus in the future exists.View full abstractDownload PDF (942K) -
Hisayo Yamane, Ryutaro Tao, Hideki Murayama, Makoto Ishiguro, Yoshiyuk ...2000 Volume 69 Issue 1 Pages 29-34
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESS'Takasago (Rockport Bigarreau)', one of the major early ripening cultivars of sweet cherry in Japan, was reported to be cross-incompatible with 'Hinode (Early Purple)'. Thus, they were assumed to have the same S-alleles, although their S-genotypes were unknown. However, when 'Takasago' was cross-pollinated with 'Hinode' at the Yamagata Prefectural Horticultural Experiment Station, the fruit set normally (unpublished data), which suggests that they are cross-compatible. In this study, we re-evaluated crossability between the two cultivars by controlled pollination tests and determined their S-genotypes by the molecular typing system recently developed for S-alleles of sweet cherry. The cross-pollination tests conducted at two different locations in Japan showed that 'Takasago' and 'Hinode' were self-incompatible but reciprocally cross-compatible. Furthermore, 2D-PAGE (two dimentional-polyacrylamide gel electrophoresis) analysis for stylar extracts revealed that they have none of the common S-RNases, S-gene products in styles of sweet cherry, which suggests that their S-genotypes are completely different. By S-RNase spot patterns in 2D-PAGE profiles and RFLP (restriction fragment length polymorphism) analysis, S-genotypes of 'Takasago' and 'Hinode' were proposed to be S1S6 and S2Sx(Sx is a novel S-allele different from S1 to S6), respectively. This implies that 'Hinode' is cross-compatible with all cultivars of known S-genotypes. The usefulness of biochemical and molecular methods for S-allele typing employed in this study is discussed.View full abstractDownload PDF (786K) -
Naohiro Kubota, Hiromi Mimura, Kazuo Shimamura2000 Volume 69 Issue 1 Pages 35-39
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSPhenolic contents in developing and mature fruits of peach (Prunus persica Batsch var. vulgaris Maxim.) and nectarine (P. persica Batsch var. nucipersica Schneid.) cultivars were compared in relation to astringency. Total phenolic contents varied widely among the peach cultivars, being low in 'Wase-momoyama, ' 'Setouchi-hakuto, ' 'Takei-hakuho, ' 'Saotome' and 'Shimizu-hakuto' and high in 'Golden Peach, ' 'Hakuto, ' 'Mishima-hakuto, ' 'Koho' and 'Koyo-hakuto' ; 'Kodaira-wase' and 'Okubo' were intermediate. The content of higher molecular fraction of phenolic compounds was positively correlated with the total phenolic concentration. Two nectarine cultivars, 'Shuho' and 'Fantasia, ' had consistently higher levels of total and higher molecular phenolic compounds. The total phenolic contents in 'Shimizu-hakuto' and 'Hakuto' peach fruit decreased toward the end of Stage 1 of their growth curve ; thereafter, they increased rapidly and reached a maximum in the middle of Stage 2, and then rapidly decreased to a lower level during Stage 3. Total and higher molecular phenolic contents were greater in 'Hakuto' than in 'Shimizu-hakuto' throughout fruit growth, especially during Stage 2. Based on these results, the degree of astringency among the peach and nectarine cultivars is discussed.View full abstractDownload PDF (674K) -
Atsushi Yamasaki, Kazuo Tanaka, Mio Yoshida, Hiroyuki Miura2000 Volume 69 Issue 1 Pages 40-46
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSEffects of day and night temperatures on flower-bud formation and bolting of Japanese bunching onion (Allium fistulosum L.) were investigated by using mid-season flowering 'Kincho' and 'Asagi-kujo', and late-season flowering 'Cho-etsu'. Exp.1. Plants were grown at 3, 7, 11, and 15°C at night and 20°C during the day for 20 to 60 days. Flower-bud formation was promoted at 3°C and, especially, at 7°C in all cultivars. More than 50% of 'Kincho' and 'Asagi-kujo' plants formed flower buds at 15°C when grown for 60 days ; only 10% of 'Cho-etsu' bolted. Exp.2. Plants were grown at 7.0, 13.5, 20.0 or 26.5°C during the day and 7.0°C at night. Bolting of 'Kincho' and 'Asagi-kujo' plants at 7.0°C and 26.5°C was slightly retarded, compared to plants exposed to 13.5°C and 20.0°C. The bolting rate of 'Cho-etsu' was lower in all day temperatures than were those of 'Kincho' and 'Asagi-kujo', irrespective of the duration of treatments. Over 60% of 'Cho-etsu' bolted when grown at 7.0°C and 13.5°C for 75 days, whereas only 33.3% bolted at 20.0°C ; no plants bolted at 26.5°C. Thus, 'Cho-etsu' plants were devernalized at day temperature 20.0°C and 26.5°C. Based on these results, the optimum night temperature for flower-bud formation of Japanese bunching onion is 7°C at 20°C during the day. Devernalization occurs in 'Cho-etsu' at and above 20°C ; it rarely occurs in 'Kincho' and 'Asagi-kujo' below 26.5°C.View full abstractDownload PDF (800K) -
Nobuyoshi Ogasawara, Manabu Kikuchi, Hideaki Takagi2000 Volume 69 Issue 1 Pages 47-51
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSPetunia cuttings were cultured in vitro for 50 days under a long lighting cycle (16-hr photoperiod) and a short lighting cycle (2 hr light/1 hr dark) in separate ventilated vessels. When the plantlets were supplied with CO2 by a continuous air flow, the short lighting cycle did not enhance plant growth, which indicates that it has no promotive effect. However, in naturally ventilated vessels, plant growth and the daily CO2 absorption and sugar uptake under the short lighting cycle were greater than those under the long lighting cycle. The increased sugar uptake in the short lighting cycle condition probably resulted from the increased CO2 uptake. With the increased CO2 uptake, the ratio of the dry weights of cuttings to sugar uptake under the short lighting cycle was greater than under the long lighting cycle. These results indicate that the short lighting cycle promotes plant growth in vitro by increasing the re-absorption of respiratory CO2 during the dark period.View full abstractDownload PDF (640K) -
Dong Sheng Han, Yoshiji Niimi, Masaru Nakano2000 Volume 69 Issue 1 Pages 52-56
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSCalli from microspores were induced for the first time in Lilium species. The uninucleate microspores of the Asiatic hybrid lily 'Connecticut King' were isolated and cultured in liquid medium, containing half strength of MS macronutrients, full strength of micronutrients, Fe-EDTA and vitamins of MS, 100 mg·liter-1 cosamino acids, 500 mg·liter-1 glutamine, 1 mg·liter-1 picloram and 0.25 M sucrose or maltose. Microspore viability and development of cultured microspores were influenced by the carbohydrate sources in culture medium. A relatively high viability rate of microspores was observed in the maltose medium, compared with that of sucrose. Cell divisions of microspores and callus formation were found in the maltose medium, whereas in the sucrose medium, a large number of swollen microspores containing many starch grains remained undivided. Hence, maltose is the preferred carbohydrate source for microspore culture of 'Connecticut King'.View full abstractDownload PDF (798K) -
Hiroo Mukai, Toshihiko Takagi, Hisashi Harada, Yasuhiro Murai2000 Volume 69 Issue 1 Pages 57-59
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSJuice vesicle explants including some mesocarp tissue excised from young satsuma mandarin (Citrus unshiu Marc. cv. Miyagawa wase) fruit, were cultured in vitro on MS solid medium supplemented with 1 mg/L BA and 5 or 10% sucrose under dark conditions at 25°C. The juice vesicles grew expansively and turned orange. The juice vesicles accumulated sugar when cultured on the medium supplemented with 10% sucrose and incubated for two months. Sugar composition in the cultured juice vesicles differed from that of fruit grown in the field. The in vitro culture of juice vesicles may aid in elucidating the mechanism of sugar accumulation and other compounds in Citrus fruit.View full abstractDownload PDF (549K) -
Daiichiro Miyajima2000 Volume 69 Issue 1 Pages 60-62
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSEmergence of zinnia (Zinnia violacea Cav.) seeds with and without their pericarps were assessed with 3 grain size of vermiculite media and 2 watering frequency at 4 temperatures. Removal of pericarps, frequency of watering, and grain size of vermiculite significantly affected percentage of emergence and the days to emergence of zinnia seeds. The effect of pericarp removal on the percentage of emergence was greatest at 15°C, then at 20°C ; the treatment had no effect at 25 and 30°C, whereas the effects of grain size of vermiculite was relatively small compared to those of frequency of watering at any temperature.View full abstractDownload PDF (526K) -
Katsumi Ohta, Hiroyo Atarashi, Yuko Shimatani, Shingo Matsumoto, Toshi ...2000 Volume 69 Issue 1 Pages 63-65
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSEffects of applying chitosan [poly-(1→4)-β-D-glucosamine] and water soluble inorganic fertilizer to soils on seedling growth of Eustoma grandiflorum (Raf.) Shinn. cv. Kairyou Wakamurasaki were investigated. The treatment of 1.0% chitosan soil mixture (w/w), combined with a fertilizer containing the same amount of nitrogen as in 1.0% chitosan, significantly promoted plant growth, compared to the treatments of 1.0% chitosan soil mixture and of fertilizer with equal or double amounts of inorganic nitrogen contained in the 1.0% chitosan, when measured 7 weeks after sowing. Nitrogen and phosphorus concentrations in the shoot and root in the fertilizer or chitosan combined treatment were higher than those in the untreated control. Chitosan supplementation into in vitro culture of seedlings also promoted plant growth regardless of chitosan concentration, compared with chitosan-free, half or full strength of Murashige-Skoog medium.View full abstractDownload PDF (491K) -
Daiichiro Miyajima, Ikumi Karito, Rieko Fujisawa2000 Volume 69 Issue 1 Pages 66-68
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSSelf-pollination and pollen germination in Japanese morning glories (Ipomoea nil Roth.) were investigated. Within the flower buds, anthers were situated under stigmas ; 90% of these anthers became situated over stigmas as the filaments elongated during anthesis. The flowers were thus selfed with approximately 40 pollen grains adhering to the stigmatic surface ; 17% of pollen germinated. The pollen to ovule ratio was 180 and there were no significant differences in seed set between flowers which were hand-pollinated with an abundance of pollen grains and those which were autonomously selfed in bags. Thus we consider the Japanese morning glories to have evolved to produce seeds primarily by selfing.View full abstractDownload PDF (490K) -
Tian Lai Li, Takamasa Seino, Wataru Ohkawa, Koki Kanahama2000 Volume 69 Issue 1 Pages 69-75
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSThe relation between the vascular system and the photosynthate translocation pathway was investigated in main stems, sympodiums, and inflorescences of tomato plants. The plants had the 1st inflorescence on the main shoot with 9 leaves, and the 1st, 2nd and 3rd lateral shoots with 3 leaves from each terminal node. The shoot alternated right- and left-handed phyllotaxis. There were 4 vascular bundles in the hypocotyl and 8 vascular bundles in the main stem and sympodiums. Four vascular bundles were located at the base of the 1st inflorescence. Two were connected to the 7th leaf and to the 2nd or 4th flowers ; the other two were connected to the 8th leaf and the 1st or 3rd flowers. When 14CO2 was fed to 7th or 8th leaf, the highest radioactivity was recovered in the internode just below the treated leaf among the internodes on the main stem and sympodiums. In each internode, particularly strong radioactivity was recovered in 3 of 8 vascular bundles. Among the pedicels in the 1st inflorescence, the highest radioactivity was recovered in the 1st and 3rd ones when the 8th leaf was treated, and in the 2nd and 4th pedicels when the 7th leaf was fed with 14CO2.View full abstractDownload PDF (899K) -
Naoya Fukuda, Kouichi Suzuki, Hideo Ikeda2000 Volume 69 Issue 1 Pages 76-83
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSEffects of supplemental lighting 23 : 00-7 : 00 on the growth and photosynthesis of vegetable crops were studied. In Experiment 1, lettuce (Lactuca sativa L.), pakchoi (Brassica campestris L. var. chinensis) and tsukena (Brassica campestris L.) grown on NFT in a greenhouse, were subjected to supplemental lighting with high pressure sodium lamps. Plants were grown for 24 days under normal photoperiod and then separated into 5 groups, as follows ; subjected to supplemental lighting 1) for 24 days, 2) first 8 days, 3) the second 8 days, 4) the last 8days of the 24 days period and control continued natural photoperiod. In Experiment 2, lettuce, garland chrysanthemum (Chrysanthemum coronarium L.) and tomato (Lycopersicon esculentum Mill.) plants were grown under the light source and 1, 2, and 3m apart horizontally away from the light source. Results obtained are as follows ; 1. In Experiment 1, supplemental lighting for 24 days increased top fresh weights of all crops. In lettuce and pakchoi, the supplemental lighting for the second 8 or last 8 days increased the top fresh weights when compared to the control. 2. In lettuce, garland chrysanthemum, and tomato, growth increased with increasing light intensity of the supplemental lighting ; in garland chrysanthemum it enhanced the dry weights of stems. 3. Supplemental lighting increased the chlorophyll concentrations as measured with a Minolta chlorophyll meter, SPAD-502 ; the increment levels corresponded to the light intensity of the supplemental lighting. The increases in SPAD values under supplemental lighting appeared on the 8th day after the onset of the supplemental lighting. However the elevated SPAD values resulting from supplemental lighting decreased to the same levels as the control during the subsequent 8 days when supplemental lighting was halted. 4. Supplemental lighting during the night accelerated the photosynthetic rates of lettuce, garland chrysanthemum, and tomato plants. In addition, plants grown under supplemental lighting maintained a higher photosynthetic rates during the day than the control plants did.View full abstractDownload PDF (1095K) -
Yuhua Li, Xiuying Hou, Liang Lin, Shixi Jing, Mingqin Deng2000 Volume 69 Issue 1 Pages 84-89
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSTo investigate why the interspecific cross Fragaria x ananassa (8x) × F. vesca (2x) gives a lower rate of viable hybrid achenes and seedlings, emasculated flowers of F. x ananassa 'Honeoye' (8x) were pollinated with pollen of 'Changsen', a clone of F. vesca (2x) originally from Changbaishan, Jilin Province, China. The intraspecific cross F. x ananassa 'Honeoye' × 'Hokowase' was used as the control. In the interspecific cross, 6 out of 10 pollinated flowers produced 303 developed achenes of which 167 seedlings were grown ; 84 were hybrids (5x) and 83 were apomicts. The germination of F. vesca pollens on the stigmas of F. x ananassa was rarely observed and the elongation of pollen tubes in the style was irregular. For the interspecific cross, in addition to normal growth of embryos with endosperm, delayed fertilization was observed as well as the suspended growth of embryos at the globular stage. Such abnormal embryos lacked endosperm development. These results indicate that abnormality in pollen germination and pollen tube elongation, and aberrant growth of embryos and endosperm could be the basis of incompatibility in the interspecific cross of F. x ananassa × F. vesca. Embryo rescue culture which prevents abortion of rudimentary embryos, which can occur in the interspecific cross in strawberries, may be the means to develop new hybrids.View full abstractDownload PDF (1118K) -
Toshiki Mori2000 Volume 69 Issue 1 Pages 90-96
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSExp. 1. Frequency distributions of strawberry seedlings for firmness and skin toughness of fruit were unimodality, exhibiting a normal distribution curve. These two traits seemed to be polygenitically inherited. A highly significant correlation (0.93∿0.98) was found between firmness and skin toughness. The heritability was estimated by : 1) comparing variances between seedlings and those of the parents, 2) computing the parent-offspring regression, and 3) analyzing the variance between the female and male factors. Broad-sense heritabilities for the firmness were 0.67, 0.90, and 0.51 ; those for the skin toughness were 0.59, 0.73, and 0.28. A highly additive genetic effect was observed but the dominance effect was small according to the analysis of variance between female and male factors ; hence, the difference between broad-sense and narrow-sense heritability was small. Exp. 2. The heritability estimated by the selection response to F2 from F1 was 0.43, and approximated values obtained by the comparison between the variance of the seedling population and that of the parents and by the analysis of variance between female and male factors. In conclusion, these two methods were more suitable than that of the parent-offspring regression for predicting heritability by the selection response. A relatively high heritability was found in the fruit firmness by any statistical method. Therefore, the implementation of clonal selection based on several generations may be more effective than that on the F1 generation. A superior clonal line could be selected from the progenies after the frequency of firm-fruited seedlings has increased and the selections hybridized in the early stages of breeding.View full abstractDownload PDF (865K) -
Pin San Xu, Yoshiji Niimi, Hajime Araki2000 Volume 69 Issue 1 Pages 97-102
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSWhen Lilium longiflorum 'Georgia' callus was induced from bulblet-scales in MS (Murashige and Skoog, 1962) medium supplemented with 5.0μM picloram, callus growth was more vigorous in liquid than on a solid medium. When the calli were transplanted to MS medium and 1/2 MS (half strength inorganic elements and full strength MS organic elements), the frequency of shoot formation (percentage of callus regenerating shoot and number shoot per callus) was higher in the solid than in the liquid medium. However, the shoot forming capacity decreased as the number of subculturing was increased. Bulblets regenerated from subcultured calli were stored at 4°C for 8 weeks and then transplanted to soil. After a 6-month cultivation in soil, when scaly leaves were indexed for viruses, the number of infected bulblets decreased in those regenerated from calli subcultured five times. Cucumber mosaic virus (CMV) was not detected. The addition of antiviral chemicals (DHT, ribavirin) in the regeneration medium (MS medium without growth regulators) had little influence on the rate of shoot regeneration from calli but increased the rate of virus-free bulblets. The addition of 50μM DHT eliminated CMV and LSV effectively to reduce infection rate of bulblets to 19% even after 6-months cultivation in a greenhouse.View full abstractDownload PDF (766K) -
Akihide Okamoto, Mizuo Nonaka, Kenichi Suto2000 Volume 69 Issue 1 Pages 103-108
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSTo verify the presence of Ryukyu azalea (Rhododendron mucronatum) genes in Kurume azalea (R. obtusum), dorsal leaf surfaces were examined on 58 progenies of Kurume azalea 'Susogonoito'× R. macrosepalum, 58 cultivars of Kurume azalea, 8 cultivars of Ryukyu azalea, 5 cultivars of Mochi azalea, and 4 cultivars of Ookirishima azalea. The epidermal cells, cuticular topography and stomata, and the existence of vein trichomes were examined and described. In progenies between Kurume azalea 'Susogonoito'× R. macrosepalum, 87.9% exhibited more than one, among 3 epidermal characters, which were similar to R. macrosepalum. Vein trichomes, which occur on R. macrosepalum, appeared on all progenies. Twenty-three of 58 cultivars of Kurume azalea had more than one, among 4 dorsal leaf surface characters, which were similar to R. macrosepalum and R. mucronatum var. ripense. Seventeen cultivars of Ryukyu azalea, Mochi azalea and Ookirishima azalea possessed dorsal surface characters which were similar to those members of R. macrosepalum and R. mucronatum var. ripense. These results suggest that R. macrosepalum and/or R. mucronatum var. ripense which are species of Ryukyu azalea, may be related to the Kurume azalea.View full abstractDownload PDF (1051K) -
Takeshi Motozu, Tomoyuki Komagata, Tsutomu Ichimura, Akira Asano2000 Volume 69 Issue 1 Pages 109-114
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSCorms of the freesia 'Blue Heaven' were chilled wet at 10°C for 5 or 6 weeks and the resulting sprouting young plants were immediately exposed to 24°C for 1, 2, or 3 weeks and then to 10°C until they were planted in a plastic house maintained at 5°C or above on 13 Nov. Flower buds, exposed to the high temperature, were prepared and photographed on a scanning electron microscope (SEM). Based on their morphology, the inflorescence types at flowering were classified into 6 categories. When flower buds were exposed to high temperature during the differentiation of floral primordia, the inflorescence which formed, varied depending on the developmental stages of flower buds at the start of the high temperature treatment and its duration. These inflorescences were classified as "normal inflorescence", "gladiolus bloom" or "abnormal inflorescence" according to the degree of heat injury. The angle between the horizontal and the crossing lines from the base of the first to that of the last floret in an inflorescence is a practical indicator to measure the degree of "gladiolus bloom". Visually normal inflorescence, "pseudo-normal inflorescence", appeared in plants which received the most severe high temperature treatment. These plants initiated leaves and flower buds after abortion of the pre-differentiated flower buds. "Normal" and "pseudo-normal" inflorescences are easily distinguished by the difference in the number of leaves or days from chilling to flowering. Heat injury was less severe if the plants were exposed to high temperatures at a more advanced stage of flower bud development.View full abstractDownload PDF (776K) -
Yuri Torata, Motoaki Doi, Hideo Imanishi2000 Volume 69 Issue 1 Pages 115-117
Published: January 15, 2000
Released on J-STAGE: January 31, 2008
JOURNAL FREE ACCESSCorms of Freesia hybrida Hort. 'Cote d'Azur' averaging 6.7g, which had been stored at 30°C for 10 weeks, were potted, exposed to seven temperature classes from 3 to 21°C for 6 weeks and then transferred to 23°C. Flower buds were observed microscopically at the end of exposure to 6, 9, 12, 15, and 18°C. The developmental stage of flower buds was most advanced at 12 and 15°C ; however, the flower buds initiated at 12, 15, and 18°C failed to develop floral parts, and the elongation of the flower stalks was greatly suppressed upon transfer to 23°C. Whereas, plants exposed to 9°C for 6 weeks consequently flowered at 23°C ; those exposed to 6°C developed malformed inflorescences having abnormally elongated bracts and lacking floral organs. At 23°C, the apical meristems of plants exposed to 3°C continued to initiate leaf primordia, while those exposed to 21°C formed bract-like organs. Daughter corm formation 10 weeks after transferring plants to 23°C was most advanced in plants previously exposed to 12°C for 6 weeks. Three directional effects of chilling : 1) direct effect on flower bud initiation, 2) after-effect on flower bud development and flower stalk elongation, and 3) direct effect and/or after-effect on corm formation, are discussed.View full abstractDownload PDF (516K)
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