Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 53 , Issue 1
Showing 1-16 articles out of 16 articles from the selected issue
  • Chuji HIRUKI
    1987 Volume 53 Issue 1 Pages 1-6
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Hitherto unreported witches' broom of Hibiscus heterophyllus, native rosella, was found in Toowoomba, Queensland, Australia. Petiole and stem tissues of both affected and normal plants were examined by light and electron microscopy. Mycoplasmalike organisms (MLOs) were detected in the phloem elements of diseased plants, but were absent from the control normal plants. In fluorescence microscopy with DAPI (4', 6-diamidino-2-phenyl-indole⋅2HCl), these MLO fluoresced specifically. After staining with aniline blue, abnormal accumulation of callose in affected phloem cells, as compared with healthy ones, was observed as strongly fluorescing spots. Phloem of diseased tissues displayed positive Dienes' staining.
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  • Yutaka ARIMOTO, Yasuo HOMMA
    1987 Volume 53 Issue 1 Pages 7-13
    Published: January 25, 1987
    Released: February 19, 2009
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    Presence of epidermal cell was essential for the induction of self-defense reaction of citrus plants when inoculated with Diaporthe citri (Faw.) Wolf. If the epidermis was removed from the plant, the self-defense reaction did not occur even if mesophyll was inoculated with the fungus or wounded with a knife mechanically. This suggests that a inducer of self-defense reaction exists in the epidermal cell, and is activated when those cells are damaged. When the self-defense reaction did not induce by penetration with D. citri due to removal of epidermis, fungus spread inside the tissues, and pycnidia and spore-horn were formed.
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  • Hisatoshi KAKU, Toshihiko KIMURA
    1987 Volume 53 Issue 1 Pages 14-20
    Published: January 25, 1987
    Released: February 19, 2009
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    Resistance expression controlled by resistance gene Xa-1 was investigated in adult plants of Kogyoku group rice cultivars after inoculation with bacterial group I isolates of X. campestris pv. oryzae. Kogyoku group cultivars with resistance gene Xa-1 showed symptomless type of resistance reaction to bacterial group I isolates irrespective of their aggressiveness. Periodical population study showed that there was distinct difference in growth patterns between compatible and incompatible isolates in the leaf tissues of cultivar Kogyoku. Compatible isolate T7147 of bacterial group II grew logarithmically and reached its maximum level above 108 cfu per inoculation site. In contrast, incompatible isolates T7174 and Q6808 of bacterial group I multiplied at a much lower rate than compatible T7147, and reached their maxima at less than 106 and 105 cfu per inoculation site, respectively. In Kogyoku, population levels of six isolates of bacterial group I 12 days after inoculation ranged approximately from 105 to 106 cfu per inoculation site. The degree of multiplication of isolates T7174 and Q6808 in nine Kogyoku group cultivars ranged approximately from 105 to 106 and 104 to 105 cfu per inoculation site, respectively, 12 days after inoculation.
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  • Hiroyuki YAMAMOTO, Toshikazu TANI
    1987 Volume 53 Issue 1 Pages 21-27
    Published: January 25, 1987
    Released: February 19, 2009
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    A rapid and efficient procedure for the isolation of intact nuclei was established with the primary leaves of oat seedlings infected with a compatible race of Puccinia coronata f. sp. avenae. The time required for the isolation was about 90min and the yeild of nuclei was estimated to be about 50% of total nuclei in all leaf samples. The content of DNA, RNA and protein in isolated nuclei was unchanged by the rust infection. However, time course study of 3H-UTP incorporation indicated that transcriptional activity increased to about 1.5-times of corresponding control at the early stage of uredosorus differentiation. The blockage experiments with α-amanitin suggested that qualitative changes in the transcription would most likely occur at this stage of infection.
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  • Shinzo KOIZUMI, Hajime KATO
    1987 Volume 53 Issue 1 Pages 28-38
    Published: January 25, 1987
    Released: February 19, 2009
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    Rice leaf blast disease incidence was investigated in mixed plantings of susceptible and resistant rice cultivars in the nursery and paddy field. In the blast nursery experiment, increase of rice leaf blast disease could be described by the equation dx/dt=rx(1-x), where x is the proportion of diseased area per plant of susceptible cultivar, t is the time in days and r is the apparent infection rate. The r value in mixed plantings of susceptible and resistant cultivars (rm) was in accordance with the equation rm=rs+clogem, where rs is r in single planting of susceptible cultivar, m is the proportion of susceptible cultivar in mixed plantings and c is a constant. In the paddy field experiment, the gradient of leaf blast disease incidence from inoculum sources which were placed in the center of plots was given by the equation log10y=A+Blog10x, where y is the number of acute-type lesions per hill of susceptible cultivar, x is the number of hills from inoculum source and A and B are parameters. The B values of plots, which represented leaf blast disease gradient from inoculum source, increased with both increasing ratio of susceptible cultivar in mixed plantings and with time. The presumed total number of acute-type lesions in plots was calculated by the equation log10y=A+Blog10x, using the A and B values for each plot. In order to compare rice leaf blast increase of each plot directly, The recalculated total number of acute-type lesions was obtained by dividing the presumed total number of acute-type lesions by the ratio of susceptible cultivar in the mixture. The recalculated total number of acute-type lesions in mixed plantings was smaller than that of single planting of susceptible cultivar. Infection rates between each investigated date which was calculated by the exponential growth model using the recalculated total number of acute-type lesions approximated Leonard's equation rm=rs+clogem.
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  • Kazuo SUZUKI, Yasuyuki HIRATSUKA, William A. AYER
    1987 Volume 53 Issue 1 Pages 39-44
    Published: January 25, 1987
    Released: February 19, 2009
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    For monitoring of the disease development of Armillaria root rot and bioassaying of toxic metabolites of Ceratocystis spp., changes in water potential components of lodgepole pine seedlings were determined by means of pressure-volume analysis. Comparisons were made with water-stressed seedlings. Under water stressed conditions, the wilting point (ψt1pw) of the seedling decreased gradually as the time advanced until chlorosis occurred. Once chlorosis appeared, a lowering of ψt1pw broke down. As to the bulk elastic modulus (ε), εmax showed no appreciable differences to the controlled conditions before chlorosis appeared. In the case of Armillaria infection, ψt1pw decreased only a little accompanied by disease development, compared with the water stressed conditions. However, εmax increased twice than that of the control. As to bioassay of toxic metabolites, a metabolite from C. minor had direct effects upon water status of lodgepole pine seedlings. The result suggests that the loss of elasticity of the cell wall was induced by absorption of the metabolite. This technique for monitoring disease development is useful for predicting changes in the water status of the tree and studying pathogenesis of certain kinds of tree disease.
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  • Katsumi AKUTSU, Makoto UCHIDA, Tatsuyuki IRINO, Satoshi OKUYAMA
    1987 Volume 53 Issue 1 Pages 45-52
    Published: January 25, 1987
    Released: February 19, 2009
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    In the presence of inosine solution containing glucose, the sclerotial formation of Botrytis cinerea was observed on glass slides 5 days after the onset of incubation. By light microscopy, the sclerotial initials arose from the hyphal tips by dichotomous branching, followed by cross-wall formation in the same way as the formation of multicellular appressoria by the fungus. The sclerotia were formed by repetition of dichotomous branching and septation, followed by deposition of pigment in the surface hyphae of spherical masses. The purine-related compounds tested (cyclic AMP, adenosine, inosine and adenine) stimulated the formation of Sclerotia. Among these compounds, inosine showed highest effect alike to that in the formation of appressoria. On rice leaves, the sclerotial formation on non-spreading lesions (necrotic lesion) was observed in the presence of inosine. On the epidermal cells around multicellular appressoria, the spherical masses of hyphae or sclerotia were formed. Necrotic reaction of the epidermal cells was found, but infection hyphae could not be observed in the cells. On cucumber leaves, invasion from the multicellular appressoria and formation of spreading lesions were observed, but the sclerotial formation was not. The present study suggested that the sclerotial formation in B. cinerea might closely be related with success or failure of infection by the multicellular appressoria.
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  • Yosuke MINO, Yasuki MATSUSHITA, Ryutaro SAKAI
    1987 Volume 53 Issue 1 Pages 53-55
    Published: January 25, 1987
    Released: February 19, 2009
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  • Susumu TAKAMATSU, Takio ICHITANI
    1987 Volume 53 Issue 1 Pages 56-59
    Published: January 25, 1987
    Released: February 19, 2009
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    Pythium iwayamai, P. okanoganense and P. paddicum, the main causal organisms of Pythium snow rot, were isolated from rotted leaves of wheat and barley grown in 122 paddy fields and 7 upland fields between 1982 and 1986. P. paddium was the dominant pathogen in ill-drained paddy fields in the previous season. From well-drained paddy fields, all three pathogens were isolated independently or simultaneously. On the other hand, P. iwayamai was the dominant pathogen in upland fields. The results indicate that distribution of the pathogens may vary with the degree of drainage in the fields.
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  • Ichiro UYEDA, Sang Yong LEE, Hideko YOSHIMOTO, Eishiro SHIKATA
    1987 Volume 53 Issue 1 Pages 60-62
    Published: January 25, 1987
    Released: February 19, 2009
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  • 1987 Volume 53 Issue 1 Pages 63-74
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1987 Volume 53 Issue 1 Pages 75-81
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1987 Volume 53 Issue 1 Pages 82-88
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1987 Volume 53 Issue 1 Pages 89-96
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1987 Volume 53 Issue 1 Pages 97-113
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • 1987 Volume 53 Issue 1 Pages 114-126
    Published: January 25, 1987
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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