Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 47 , Issue 2
Showing 1-22 articles out of 22 articles from the selected issue
  • Yasuo HOMMA, Hiroharu TAKAHASHI, Yutaka ARIMOTO, Takehiro ISHIKAWA, Iz ...
    1981 Volume 47 Issue 2 Pages 143-150
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The formation of conidiophores and conidia were observed under an optical and scanning electron microscope. Leveillula taurica is one of a few endophytic species of powdery mildew. From inoculation to the emergence of fungus through stomata, it takes 3 days in summer and 7 days in winter. However, it was found in our experiments that this fungus was not only endoparasitic, but that it also had a creeping habit on the surface of pepper plants to form conidiophores on superficial mycelia (8%). Conidia were formed within 20 hours of conidiophore formation. Primary and secondary conidia differed markedly: primary conidia were boat-like in shape while secondary conidia were elliptical. The conidia were about 130×30μm in size, with thorn-like projections on the surface. Such projections were also recognized on the surface of conidiophores, on which they were concentrated on about the upper two-thirds of the surface below the conidia. They gradually thinned out and none were found on the conidiophore-base. This thorn-like projection on conidia and conidiophores is one of the features of L. taurica. Several kinds of exophytic species, Sphaerotheca fuliginea, Erysiphe graminis, Cystotheca lanestris and Oidium euonymi-japonicae do not have such thorn-like projections either on their conidia or on their hyphae. Judging from the phenomena that conidia easily adhered to the abaxial surface of pepper leaves or a needle when they were gently attached, and in rare cases printed their traces on a slide glass when they were stirred with a needle after being attached to it, the surface of the conidia may possess some adhesive substance.
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  • Takio ICHITANI, Toshinori SHINSU
    1981 Volume 47 Issue 2 Pages 151-157
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The present paper deals with the relation of changes in the pathogen population to the incidence and development of the rhizome rot disease of ginger in continuous indoor cropping for immature rhizome production. The number of seed pieces contaminated by the pathogen varies from year to year. Isolation of pathogen from the field soil sterilized prior to planting was failed. Results obtained from the present experiment indicated that the disease outbreak was caused by planting of infected seed pieces. The propagules of the pathogen increased in both rhizosphere and non-rhizosphere soils during and after the secondary infection, and form of the propagules in these soils was estimated to be mycelial fragments or sporangia-like bodies from microscopic observation of colonies growing on selective medium. The pathogen was still detected from a soil just before the planting of ginger, although it decreased in general remarkably during the preceding cropping in the same soil.
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  • Takio ICHITANI, Toshinori SHINSU
    1981 Volume 47 Issue 2 Pages 158-165
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    This study deals with the relation of distribution of the pathogen causing rhizome rot disease of ginger in soils adjacent to plastic houses to the disease outbreak in continuous indoor cropping for immature rhizome production. At least three species of Pythium were found in soils adjacent to plastic houses. Pythium zingiberum, which is less abundant than the other species, was found to be pathogenic to the young ginger plants. No definite role of the pathogen for primary infection was found although the fungus was detected in soils adjacent to the house with history of rhizome rot disease. The population of pathogen decreased rapidly in dumping place for ginger refuse. The pathogen in sufficient inoculum potentials for disease outbreak was detected most often along the drainage canal where ginger rhizomes were washed.
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  • Kinji TANAKA, Fukuji NONAKA
    1981 Volume 47 Issue 2 Pages 166-174
    Published: April 25, 1981
    Released: February 19, 2009
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    Oxalic acid production and pectolytic enzyme activity were detected in inoculated onion bulb tissues by Aspergillus niger. A chain-splitting enzyme, which reduced the viscosity of polygalacturonate, from inoculated onion bulb tissues was purified 22-fold by ammonium sulfate fractionation, SP-Sephadex column chromatography and gel filtration of Sephadex G-100. The purified enzyme formed a single protein band on polyacrylamide gel electrophoresis. Among 7 plant species tested, onion tissue was the most macerated by the enzyme itself. The optimum pH for the enzyme activity was 3.0 on onion tissues and the enzyme lost activity at 70C for 10min. Oxalic acid production and macerating activity in inoculated onion bulb tissues increased progressively with incubation time. Oxalic acid was as much as 6.6mg/g fresh weight in inoculated onion bulb tissues 10 days after incubation and pH of the onion tissues dropped from 6.5 to 1.9. A possible synergistic role for each of these constituents produced in rot of onion bulbs is indicated by our results that lowering of pH of the bulb tissues by oxalic acid provided the activity of the enzyme with the optimum pH value in the bulb tissues.
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  • Toshiro SHIDA, Yasuo HOMMA, Tomomasa MISATO
    1981 Volume 47 Issue 2 Pages 175-181
    Published: April 25, 1981
    Released: February 19, 2009
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    Preventive effect of N-lauroyl-L-valine and its analogs against rice blast disease was related to their wetting power, and the amounts of intracellular substances leaked from the fungus. A deform of the mycelia of the fungus treated with N-lauroyl-L-valine was observed with a scanning electron microscope. The difference was found in the amounts of intracellular substances leaked from the fungus treated with N-lauroyl-L-valine, N-lauroyl-DL-valine and N-lauroyl-D-valine. From these results, it is concluded that the primary action of N-lauroyl-L-valine on the rice blast fungus may be the leakage of intracellular substances of the fungus by the surfactant action of the acylamino acid.
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  • Narinobu INOUYE, Kuniaki MIYAJI, Koji MITSUHATA
    1981 Volume 47 Issue 2 Pages 182-188
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Pronounced mosaic symptoms are commonly observed in many cultivars of bulbous iris in Japan. The causal virus was transmitted readily by aphids (Aphis gossypii and Myzus persicae) in the non-persistent manner. It was also transmitted by sap-inoculation to 6 of 44 plant species in 13 families. Bulbous iris (Dutch iris) was infected systemically and exhibited pronounced mosaic symptoms. Local lesions were produced on Chenopodium amaranticolor, C. quinoa, Tetragonia expansa, Gomphrena globosa and Nicotiana clevelandii, but G. globosa was infected with difficulty while N. clevelandii was infected without visible symptoms. The presence of the virus in these plants was confirmed by immuno-electron microscopy with antiserum against iris severe mosaic virus (ISMV). Sap from the diseased T. expansa was infective after 10min at 60C but not 65C, after dilution to 10-3 but not 10-4, or 3-4days at 20C. The virus particles were filamentous, about 750×13nm. In ultrathin sections of diseased plant leaf tissue, pinwheel and laminated aggregate inclusions were observed in the cytoplasm in the cells. The inclusions found in negatively stained dip-preparations exhibited fine striations with a periodicity of 5.3nm. In immuno-electron microscopy, the virus particles reacted with ISMV antiserum, but not with iris mild mosaic virus antiserum. The virus did not react with antisera against turnip mosaic virus, potato virus Y and bean yellow mosaic virus, in micro-precipitin test. Based on the result mentioned above, the virus was identified as iris severe mosaic virus.
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  • Masayuki NOZUE, Kohei TOMIYAMA, Noriyuki DOKE
    1981 Volume 47 Issue 2 Pages 189-193
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Effect of p-chloromercuribenzoic acid (PCMB), dextran-bound PCMB (PMDT), 2, 4-dinitrophenol (DNP), sodium azide (NaN3) on the binding between the host plasmalemma and hyphal wall was determined by observing plasmolytic behavior of cells of potato tuber disks which had been treated with these inhibitors and inoculated with compatible or incompatible race of Phytophthora infestans. Light microscopic observations showed that regardless of the treatment with these inhibitors, the infected cells were plasmolyzed in a tent-type shape. This phenomena indicated that the host plasmalemma adhered the intercellular hyphal surface from the very onset of the infection. Electron microscopic observations of the plasmolyzed cells also showed that the plasmalemma of the cells which had been treated with NaN3, PMDT or water and then inoculated by an incompatible race, adhered to the surface of the infecting hyphae. These results clearly indicated that NaN3, DNP, PCMB and PMDT had no apparent effect on the firm binding between host plasmalemma and hyphal surface. Thus, the inhibition of the hypersenitive cell death of infected potato tissues by these inhibitors could hardly be due to interference of binding between the host plasmalemma and hyphal surface, which is necessary for the occurrence of the cell death.
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  • Teruyoshi HASHIBA, Hiroshi UCHIYAMADA, Kenji KIMURA
    1981 Volume 47 Issue 2 Pages 194-198
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The methods to estimate the severity of rice sheath blight disease caused by Rhizoctonia solani Kühn were investigated with an aim to find a method which saves time and makes simple to test it. Rice cultivars, 1429 foreign cultivars from more than 40 countries of the world and 277 domestic cultivars, were tested for the height of the uppermost infected parts of rice plants, percentage of the height of the uppermost infected parts to the plant height and the degree of disease incidence estimated by the Yoshimura's method. All cultivars were inoculated by putting bits of the mycelia grown on wheat bran medium into the hills on July 15, 1976, and vertical development of the disease was assessed on September 1 to 6. Vertical development of the disease was always more extensive in early maturing cultivars than in late maturing ones. Statistical analysis enabled one to estimate the degree of disease incidence (Y) from percentage of the height of the uppermost infected parts to the plant height (X) by the following expression, Y=1.62X-32.4. The value X was estimated as X=0.73Z-4.13, where Z is the height of the uppermost infected parts. Estimating of the degree of disease incidence according to these formulae is more efficient and simple than one according to the Yoshimura's method.
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  • Jae Eul CHOI, Nobuaki MATSUYAMA, Satoshi WAKIMOTO
    1981 Volume 47 Issue 2 Pages 199-205
    Published: April 25, 1981
    Released: February 19, 2009
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    The diffusible antigens of Xanthomonas campestris pv. oryzae were analyzed by using antisera prepared with the isolates Q7472 (serovar A), Q7502 (serovar B-I) and N5837 (serovar B-II). When these antisera were added to the slime polysaccharide and somatic polysaccharide of the isolates Q7472, Q7502 and N5837 in test tubes, precipitation of the antibody occurred showing different quantitative curves, suggesting that slime and somatic polysaccharides of these isolates were not identical serologically. In agar gel diffusion test, the suspensions of whole cells, slime polysaccharide and somatic polysaccharide of the isolate Q7472 produced a few precipitin bands with all antisera. Among these antigens, the antigen named “a” was specific for serovar A. It was extracted with distilled water, saline solution and 0.5 N trichloroacetic acid and formed thick precipitin band with both homologous and heterologous antisera in agar gel diffusion test. It was heat stable, precipitated with ethanol and not affeced by Pronase treatment. All antigens other than “a” were not specific for serovars.
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  • Hitoshi KUNOH, Hitoshi TAKESHIMA, Hiroshi ISHIZAKI
    1981 Volume 47 Issue 2 Pages 206-212
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Earlier ultrastructural studies have shown that osmiophillic granules are prominent around and inside of haustoria and intercellular hyphae of Leveillula taurica (Lev.) Arn, in mesophyll cells of green pepper, Capsicum annuum L. var. angulosum Mill. Electron microscopy led us to speculate by electron density and appearance that these granules are lipid bodies and/or lysosomes. The present study was undertaken to investigate histochemical natures of these granules. Light microscopy revealed that the granules are more prominent around and inside fully-developed haustoria than incipient ones. Various stains and histochemical tests indicated that the granules contained neutral, unsaturated lipids and lipoids but not phospholipids, and that the acid phosphatase activity was not detected in the granules. This suggests that the osmiophillic granules simply correspond to lipid bodies and not to lysosomes.
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  • Kiyoshi ISHIGURO, Tadao UI
    1981 Volume 47 Issue 2 Pages 213-217
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Oospores of Phytophthora vignae were prepared by repeated floatation and sedimentation of macerated colonies on V-8 Juice agar containing β-sitosterol. Approximately 106 of almost pure oospores were harvested from an agar plated culture in 9cm Petri-dish. Some of the oospores formed in the dark at 25C, germinated even 10 days after they were produced. The percentage of germination increased with their age, being highest from 20 to 90 days after they were produced. Oospores, 30days old, germinated with or without light during their production and germination, though it stimulated the germination and increased the percentage.
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  • Kiyoshi ISHIGURO, Tadao UI
    1981 Volume 47 Issue 2 Pages 218-221
    Published: April 25, 1981
    Released: February 19, 2009
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    The osmotic potential of the agar medium exerted some effect on oospore germination of Phytophthora vignae irrespective of the solute used for osmotic potential control (KCl, NaCl, glucose and mannose). Few oospores germinated at -3.0 bars. Decline in osmotic potential did not increase the latent period of oospore germination. The terminal sporangium was produced on the germ tube developed through oogonial stalk when solutes other than glucose were used.
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  • Noboru SHIRANE, Tomonori SHIRAISHI, Hachiro OKU, Seiji OUCHI
    1981 Volume 47 Issue 2 Pages 222-227
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    No significant difference in pisatin degradation but apparent difference in biosynthesis was found between compatible and incompatible pea plants inoculated with powdery mildew fungi. When leaves of pea cultivar “Alaska” were inoculated with a compatible race of Erysiphe pisi DC. and were incorporated with 14C-phenylalanine, 14C-pisatin was first detected 12hr after inoculation, and increased thereafter. By inoculation with a nonpathogen of pea, E. graminis DC. f. sp. hordei Marchal, pisatin biosynthesis occurred much earlier, 6hr after inoculation. When leaves of pea cultivar “Resistant Stratagem” were inoculated with a compatible race of E. pisi (OEP-2) and fed with 14C-phenylalanine, 14C-pisatin could be detected 13.5hr after inoculation and the radioactivity remained very low until 18hr after inoculation. 14C-Pisatin was detectable 10.5hr after inoculation and then increased rapidly when leaves of “Resistant Stratagem” were inoculated with an incompatible race of E. pisi (OEP-1). These results suggest that the accumulation of pisatin in pea leaves infected by powdery mildew fungi might be due to the activation of the biosynthetic pathway of pisatin, rather than the blocking of pisatin degradation.
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  • Keido Ko, Katsumi AKUTSU, Yumiko KOBAYASHI, Yunsil OM, Tadakazu WATANA ...
    1981 Volume 47 Issue 2 Pages 228-233
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Purine and their relative compounds were found to accelerate the infection and lesion formation caused by gray mold fungus, Botrytis cinerea, on cucumber seedling in the presence of glucose at the concentration more than 2.5%. The required concentration of all these compounds for exhibiting their action on the gray mold fungus to accelerated the infection and lesion formation were more than 1×10-5M. All pyrimidines, however, were not effective, even at the concentration of 1×10-3M. Among the purines, the tri- and the mono-phosphates were much more effective; whereas the free bases and the diphosphates were somewhat less effective. Some metabolites of purines, uric acid, allantoin and allantoic acid were considerably effective as well as that of ATP and AMP.
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  • Katsumi AKUTSU, Yumiko KOBAYASHI, Yasuhide MATSUZAWA, Tadakazu WATANAB ...
    1981 Volume 47 Issue 2 Pages 234-243
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Conidia of Botrytis cinerea caused typical lesions on cucumber leaves in the presence of purine-related compound (ATP, ADP, cyclic AMP, AMP, IMP, adenosine, inosine, adenine and uric acid) or allantoic acid solution containing glucose. In order to investigate the process of infection by B. cinerea stimulated with the purine-related compound or allantoic acid solution containing glucose, we examined each infection process by the fungal conidia in the presence of the solution on cucumber leaf disks under light microscope. In glucose solution, the conidia germinated, formed primary appressoria and elongated superficial hyphae, but invasion into cucumber leaves was not observed. In purine-related compound solution containing glucose, the conidia formed secondary appressoria after elongation of superficial hyphae, and invasion by them was observed. The secondary appressoria seem to belong to the multicellular type of compound appressoria group, according to Emmett's classfication of appressoria. Among purine-related compound solutions, inosine solution showed the most remarkable effects on lesion formation and induction of the secondary appressoria. Next, we examined the role of glucose and inosine in infection process by B. cinerea on cucumber leaves. When glucose solution was removed within 16hr after inoculation and inosine solution was added instead, formation of the secondary appressoria and lesions was not observed. Formation of the secondary appressoria and lesions was observed with the removal of glucose solution beyond 18hr after inoculation and alternative addition of inosine solution, especially when the glucose solution was removed after 18-24hr of inoculation, the secondary appressoria and lesion formation was the most remarkable. The above results suggest that glucose plays important role in the conidial germination, formation of the primary appressoria and following elongation of the superficial hyphae, and that inosine plays important role in the secondary appressoria formation and their invasion into cucumber leaves.
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  • Jae Eul CHOI, Nobuaki MATSUYAMA, Satoshi WAKIMOTO
    1981 Volume 47 Issue 2 Pages 244-251
    Published: April 25, 1981
    Released: February 19, 2009
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    Several colony type variants of Xanthomonas campestris pv. oryzae developed during subculture of the pathogen on PSA medium. These variants were easily distinguished from the wild type of large-waxy yellow (Lw) colonies and were divided into five types according to their colony size and appearance, i. e., large-halo (Lh), large-dark yellow (Ld), large-white (Lwh), small-transparent (St) and small-mucoid (Sm). The variants of St and Sm types did not develop during 2 months of subculture, but after that, their populations increased with increase of subculture period. The frequency of development of small colony variants from large colony types varied depending upon isolates or clones. All of the Lw clones and most of the Lh variants belonged to serovar A. On the other hand, a part of the Lh and most of the Ld variants belonged to serovar B-I and all of the St and Sm type variants belonged to serovar B-II. Both serovars B-I and B-II were lacking in antigen “a”. From serological point of view, the colony types Lh, Ld and Lwh were considered to be the intermediates of variation from Lw to St or Sm. A close correlation was observed between autoagglutination in 1% CaCl2 solution and serovars.
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  • Iwasaburo GOTO, Yeong-Liang JAW, Ahmed Ali BALUCH
    1981 Volume 47 Issue 2 Pages 252-254
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Susumu SAKAI, Kohei TOMIYAMA, Noriyuki DOKE
    1981 Volume 47 Issue 2 Pages 255-257
    Published: April 25, 1981
    Released: February 19, 2009
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  • Shigetou NAMBA, Shuichi YAMASHITA, Yoji DOI, Kiyoshi YORA
    1981 Volume 47 Issue 2 Pages 258-263
    Published: April 25, 1981
    Released: February 19, 2009
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    Thin sections (0.5-8.0 mm thick) were prepared from fresh tissues of plants infected with phloem-limited viruses (yellows-type viruses) or mycoplasma-like organisms (MLOs). When observed under a reflecting fluorescence microscope (RFM) (Type: Olympus BHS-RF-A), they distinctly showed a yellow fluorescence in their phloem tissues. Such a fluorescence was never found in those of healthy plants. By electron microscopy of the same materials, the fluorescence was proved to originate in necrotic phloem cells. From these results, the direct detection of fluorescing cells in phloem tissues under RFM is concluded to be suitable for the diagnosis of infections by phloem-limited viruses or MLOs. We named it “direct fluorescence detection method (DFD method)”.
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  • Shigeru KUWATA, Susumu KUBO
    1981 Volume 47 Issue 2 Pages 264-268
    Published: April 25, 1981
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Sakae ARASE, Setsumi ITOI
    1981 Volume 47 Issue 2 Pages 269-271
    Published: April 25, 1981
    Released: February 19, 2009
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  • Kenji KITAZAWA, Rinzo SATO
    1981 Volume 47 Issue 2 Pages 272-274
    Published: April 25, 1981
    Released: February 19, 2009
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    Verticillium wilt of alfalfa (Medicago sativa L.) caused by V. albo-atrum occurred in Hokkaido in 1980. Diseased plants showed both wilting and yellowing of tops. Vascular bundles were brown, but no external symptoms were observed on roots. Plants with severe damage stunted and sometimes died. This fungus was pathogenic to egg-plant, tomato, cucumber, Japanese radish, and spinach in additon to alfalfa.
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