Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 49 , Issue 1
Showing 1-18 articles out of 18 articles from the selected issue
  • Wen-hsiung KO, Wang-ching HO
    1983 Volume 49 Issue 1 Pages 1-9
    Published: January 25, 1983
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Growth of mycelia and germination of sporangia amended with root extract on soil surface were used to detect soils suppressive to Rhizoctonia solani and Pythium splendens, respectively. In tests with 30 soil samples collected from various locations in Hawaii, 5 inhibited growth of R. solani more than 50% and 8 inhibited sporangial germination of P. splendens more than 50% as compared with conducive soil. Three of the soils were suppressive to both R. solani and P. splendens. Steaming the soil for 10-15min at 97-98C eliminated suppressiveness as evidenced by no reduction of either mycelial growth of R. solani or sporangial germination of P. splendens. Steam treatment reduced populations of fungi, actinomycetes, and bacteria in suppressive soils to approximately 0.04%, 1% and 5%, respectively, of the original numbers. Propylene oxide treatment and autoclaving increased inhibition on some soils. Similar effects were not found on steam-treated soils. The results indicate that suppressive soils may exist in small islands in a field and that the degree of suppressivenss variees from location to location.
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  • Takanori MAEDA, Satoshi WAKIMOTO, Narinobu INOUYE
    1983 Volume 49 Issue 1 Pages 10-17
    Published: January 25, 1983
    Released: February 19, 2009
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    Twenty-nine isolates of cucumber mosaic virus (CMV) obtained from 29 plants of 20 species in 11 families collected from Japan were compared serologically with CMV-Y (the yellow strain of CMV) in double diffusion test. Twenty-five isolates out of 29 were serologically identical to CMV-Y, while an isolate from Zinnia elegans (designated as CMV-Z), two isolates from Petasites japonicus (respectively designated as CMV-P1 and CMV-P2) and an isolate from Farfugium japonicum were not identical to CMV-Y serologically because they produced distinct spurs in agar gel.
    Antisera Y-F-IV and Z-F-IV respectively prepared by injecting formaldehyde-fixed CMV-Y and CMV-Z in rabbits intravenously reacted sufficiently with virus particles of both strains CMV-Y and CMV-Z, while they did not react with D-proteins of these strains. The precipitin bands produced between CMV-Y and CMV-Z, CMV-P1 or CMV-P2 showed distinct spurs when they were tested against antiserum Y-F-IV. However, the precipitin bands of these 4 isolates against Z-F-IV were fused with each other without spur. No precipitin bands developed against antiserum Y-F-IV or Z-F-IV if CMV D-proteins were used as antigens. Antiserum Y-IM obtained by intramuscular injection of unfixed CMV-Y contained antibodies specific for both CMV particles and D-proteins. When antiserum Y-IM was used, spur was formed between precipitin bands of CMV-Y and CMV-Z. However, antiserum Y-IM reacted with D-proteins of these strains resulting in fusion of precipitin bands. Antiserum Y-Dp-IM raised against D-protein prepared from CMV-Y by CaCl2 treatment reacted with D-proteins of both CMV-Y and CMV-Z with spur formation, but did not react with intact virus particles.
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  • Mitsuro HYAKUMACHI, Yoshinobu YAMAMOTO, Tadao UI
    1983 Volume 49 Issue 1 Pages 18-21
    Published: January 25, 1983
    Released: February 19, 2009
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    Survival and pathogenicity of sclerotia produced by sugarbeet root rot fungus (Rhizoctonia solani AG-2 Type-2) were compared among fields with different degree of disease incidence (DI). In the Hombetsu area with high DI, sclerotial formation (SF) was not abundant, but sclerotial germination (SG) in the next spring was high. In the Kiyokawa area with low DI, SF was abundant, but SG was low. It can therefore be seen that the number of overwintered viable sclerotia (NVS) was almost same between the Hombetsu and Kiyokawa areas. There are quite high positive correlations between NVS and the DI of sugarbeet root rot. And there is a tendency for the DI in the Hombetsu area to be rather higher than in the Kiyokawa area. As there is a high positive correlation between the percentage of SG and that of sclerotia with 5 or more emerged hyphae, the difference of the DI in different areas is due to the difference of activity of sclerotia as inoculum.
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  • Ichiro FUJISAWA, Tsuneo TSUCHIZAKI, Norio IIZUKA
    1983 Volume 49 Issue 1 Pages 22-31
    Published: January 25, 1983
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    A purification procedure for beet mosaic virus (BMV) was improved. The infected swiss chard (Beta vulgaris var. cicla L.) leaves were homogenized with 0.5M borate buffer, pH 8.0, containing 0.05M ethylenediaminetetraacetic acid and 0.1% thioglycolic acid. After clarification with 1% Triton X-100, the virus was concentrated by precipitation with 4% polyethylene glycol (MW 6, 000) (PEG), and centrifugation utilizing 30% sucrose cushion containing 4% PEG, and further purified by rate zonal sucrose density-gradient centrifugation. The ultraviolet absorption spectrum of the purified preparation with a maximum at 260nm and a minimum at 243nm was typical for the potyviruses. The yield of purified virus was about 0.5∼0.7mg per 100g of infected swiss chard leaves. The titer of the antiserum against BMV was 1/512 by ring interface precipitin test. In sodium laurylsulfate-immunodiffusion test, this antiserum reacted not only with purified BMV but also with crude sap of BMV-infected leaves. No reactions were detected with some other potyviruses including turnip mosaic virus, bean yellow mosaic virus, lettuce mosaic virus and potato virus Y.
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  • Takahiro MAKINO
    1983 Volume 49 Issue 1 Pages 32-37
    Published: January 25, 1983
    Released: February 19, 2009
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    Ice-nucleation activity was measured with the bacteria isolated from gemmisphere of tea trees. The highest activity was obtained with a dominant bacterium which was coded as TGB-2 tentatively and characterized by yellow colonys on nutrient agar plate. The maximum and mean freezing temperatures of the bacterium by micropipette method were -2 and -2.7C, respectively. Population of the bacterium showed seasonal changes on gemmisphere of tea trees from the first frost season through the last frost season. The maximum population reached 106 cells/g of fresh buds from late April to early May. Because the highest activity of the bacterium maintained even at the dilution rate of 106 cells/ml, it was suggested that dew on tea buds could possibly be frozen at higher temperature in late April to early May when gemmisphere population of the bacterium increased over 106 cells/g of fresh buds. The freezing activity at cooler temperature (-8 to -12C) did not necessarily required the presence of intact cells. Ice-nucleation activity greatly decreased by treating bacterial suspension at 40C for 5min and was completely lost by heating it at 80C. Hydrogen peroxide showed no effect on ice-nucleation activity but calcium hypochlorite completely destroyed it. Methylene blue, safranin and tween 80 also reduce ice-nucleation activity.
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  • Mitsuru KOHNO, Hiroshi ISHIZAKI, Ping-Hung LIN, Kazuo YAMAMORI, Hitosh ...
    1983 Volume 49 Issue 1 Pages 38-46
    Published: January 25, 1983
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Polyoxin-B-treated and untreated (control) hypae of Alternaria kikuchiana Tanaka were first degraded with 2N NaOH, 1N H2SO4, and digestive enzymes, and then morphological alterations of the cell walls were investigated by cytochemical methods and electron microscopy. A pronounced difference between control and treated hyphae was seen after sequential treatment with NaOH-H2SO4-NaOH. Inner wall layers of controls were transformed into numerous microfibrils; these were identified, in turn, by chitinase and Lytic enzyme digestions as chitin and β-1, 3-glucan intermixed with protein. But these same treatments failed to structurally degrade the walls of polyoxin-treated hyphae. In the controls, only the thin outer wall layer showed any resistance to the treatment, but in polyoxin-treated hyphae the entire cell wall, including septae and walls of intracellular hypha, was resistant to a sequence of the degradative treatments. Cytochemical tests revealed that both control and polyoxin-treated hyphae, which originally contained chitin, no longer responded positively to tests for chitin after chitinase or HCl treatment following treatment with the NaOH-H2SO4-NaOH sequence. This study suggests two possibilities i) cell walls, especially inner wall layers, of control and polyoxin-treated hyphae may have different structural constituents, and ii) melanin-like pigments in inner cell walls may be associated with the resistance of polyoxin-treated hyphae to lysis by digestive enzymes.
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  • Kenichi TSUCHIYA, Satoshi WAKIMOTO
    1983 Volume 49 Issue 1 Pages 47-55
    Published: January 25, 1983
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Reactions of tobacco leaf tissues infiltrated with either wild types or induced mutants of Xanthomonas campestris pv. oryzae were investigated. Leaf areas infiltrated with high concentration levels (more than 107 cells/ml) of virulent strains developed yellowing discoloration followed by necrosis of hypersensitive-like reaction (HLR) by 96hr after infiltration. The development of necrosis was much delayed with weakly virulent mutants and no necrotic lesions developed with avirulent mutants. Virulent revertants induced from avirulent mutant regained inductivity of necrosis, suggesting that close relationship exists between the virulence to rice and necrosis inductivity to an uncongenial plant of tobacco. Population changes in tobacco leaf tissues were different between virulent and avirulent strains, that is, the population sharply decreased accompanied with development of necrosis in the former, while it was remained constant or gradually declined in the latter.
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  • Ryozo YOKOSAWA, Shiro KUNINAGA
    1983 Volume 49 Issue 1 Pages 56-62
    Published: January 25, 1983
    Released: February 19, 2009
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    The effect of light on oospore germination of Aphanomyces euteiches was investigated. Of 29 isolates, from 5 districts in Japan, 7 were obviously promoted oospore germination by light exposure. Two isolates AE-F10 and AE-M3a were studied in detail. More than 90% of isolate AE-F10 oospores germinated with 10 days of 2, 000lux white fluorescent light exposure at 28C. About 20% of isolate AE-F10 oospores germinated with the exposure to 50lux light for 15 days. Oospore germination of isolate AE-M3a was not promoted by light exposure. Light exposure under low temperature also promoted isolate AE-F10 oospore germination and about 50% of oospores germinated with light exposure for 10 days at 5C. Light exposure to oospores born in culture which was younger than 30 days did not promote germination. Oospores of both isolates germinated only low proportion by the aging of 10 to 150 days on water agar.
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  • Takahito SUZUI
    1983 Volume 49 Issue 1 Pages 63-65
    Published: January 25, 1983
    Released: February 19, 2009
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  • Hiroshi TANAKA
    1983 Volume 49 Issue 1 Pages 66-68
    Published: January 25, 1983
    Released: February 19, 2009
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  • Tsugufumi OGAWA
    1983 Volume 49 Issue 1 Pages 69-72
    Published: January 25, 1983
    Released: February 19, 2009
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  • Toshihiro OMURA, Yasuo SAITO, Tomio USUGI, Hiroyuki HIBINO
    1983 Volume 49 Issue 1 Pages 73-76
    Published: January 25, 1983
    Released: February 19, 2009
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  • 1983 Volume 49 Issue 1 Pages 77-83
    Published: January 25, 1983
    Released: February 19, 2009
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  • 1983 Volume 49 Issue 1 Pages 84-89
    Published: January 25, 1983
    Released: February 19, 2009
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  • 1983 Volume 49 Issue 1 Pages 89-97
    Published: January 25, 1983
    Released: February 19, 2009
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  • 1983 Volume 49 Issue 1 Pages 97-115
    Published: January 25, 1983
    Released: February 19, 2009
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  • 1983 Volume 49 Issue 1 Pages 115-124
    Published: January 25, 1983
    Released: February 19, 2009
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  • 1983 Volume 49 Issue 1 Pages 124-134
    Published: January 25, 1983
    Released: February 19, 2009
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