Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 41 , Issue 1
Showing 1-19 articles out of 19 articles from the selected issue
  • Toshiro KATO, Shizuya TANAKA, Shigeo YAMAMOTO, Yasuo KAWASE, Minoru UE ...
    1975 Volume 41 Issue 1 Pages 1-8
    Published: January 25, 1975
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Fungitoxic properties of a new compound, S-n-butyl S'-p-tert-butylbenzyl N-3-pyridylimidodithiocarbonate (S-1358), were examined. Some genera in Ascomycetes and Fungi Imperfecti were highly sensitive to S-1358 in vitro. Powdery mildews of cucumber and barley were controlled at extremely low concentrations of the fungicide, whether it was applied preventively or curatively.
    Microscopic observation showed that S-1358 did not inhibit conidial germination of Sphaerotheca fuliginea but suppressed further extension of germ tubes, causing swelling of their tips. Moreover, the same morphological effect was observed at any concentration ranging from 1ppm to 1000ppm. These facts suggest that S-1358 has influence on cell membrane or cell wall in fungi.
    Another important feature of S-1358 was that it prevented powdery mildew beyond the edge of fungicidal deposits on cucumber leaves, liberating fungitoxic vapor which may contribute to controlling diseases in field conditions.
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  • Masao GOTO, Kouki OHTA, Norio OKABE
    1975 Volume 41 Issue 1 Pages 9-14
    Published: January 25, 1975
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Xanthomonas citri (Hasse) Dowson could be detected from a grass, Zoysia japonica, growing along the paths in citrus groves all the year round. The isolates obtained from the grass were phage-typed. Frequency of each phage-type was as follow: phage-type A…11 isolates (38%), B…13 isolates (45%) and C…5 isolates (17%). Population density surviving on the grass was generally less than 103 cells per gram samples. It was interested that the isolation frequency of phage-type C from the grass was higher than that from diseased citrus plants.
    Detection ratio of X. citri from Zoysia japonica was generally higher in late autumn through winter than in summer. Phage-type A and C were frequently detected in winter, whereas phage-type B in summer.
    To investigate whether X. citri detected from the grass had originated in direct dispersion from the canker lesions by rain splash, the phage-types isolated from Zoysia japonica were compared with those from diseased citrus trees grown nearby. Only the isolates belonged to phage-type B were isolated from canker lesions on Unshu trees which were grown most close to the grass. On the other hand, phage-type A was found on the other citrus trees such as navel orange, lemons, Natsudaidai etc., which were grown 80 to 100m away from the colonies of the grass, and interrupted by the three lines of tall trees of Pondocarpus chinensis planted as wind breaks. No isolate of phage-type C was detected from any citrus plants. From these facts, it was considered that the phage-type C had been surviving on Zoysia japonica independently from the diseased citrus trees. The phage-type A was also assumed to survive fairly long period of time on the grass because it was repeatedly detected from the grass even several months after typhoon which might be responsible for dispersion of the bacterium from the lesions. The population density of phage-type B in canker lesions of Unshu trees quickly declined by autumn so that the isolation of the bacterium after late autumn became very difficult by the conventional methods. Nevertheless, the phage-type B was isolated from the grass in winter through the next spring. Therefore, the phage-type B was also considered to survive on the grass for at least several months under natural conditions.
    X. citri could be isolated from the colonies of Zoysia japonica which were collected at the distance of 600m from citrus trees. However, detection of the bacterium was difficult from the grass in area where no citrus tree was grown.
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  • Yoshio EHARA, Tadao MISAWA
    1975 Volume 41 Issue 1 Pages 15-23
    Published: January 25, 1975
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Spreading of cucumber mosaic virus in cowpea leaf tissues was investigated in relation to the formation of local lesions. The following results were obtained.
    1) Local lesions appeared more slowly but the size was larger at 20C than at 30C.
    2) Spreading of the virus from the epidermis to the second cell layer (adjacent to the epidermis) was faster at 30C than at 20C, judging from the experiment in which diluted HCl was treated on the epidermis for destroying epidermal functions. Spreading of virus from the epidermis to the third cell layer (adjacent to the second cell layer) was also faster at 30C than at 20C, judging from the experiment in which the epidermis were stripped (the second cell layer was naturally destroyed by this treatment).
    3) The time of spreading of the virus from the second cell layer to the third cell layer was calculated and it was faster at 30C than at 20C, but was equal, under the same temperature, in both inoculations with virus particles and its nucleic acid.
    4) Temperatures were changed from 30C to 20C or vice versa at the time of virus spreading from epidermis to second or third cell layer. Time of local lesion appearance and the lesion size under the altered temperature conditions confirmed the time-course of virus spreading through leaf cell layers mentioned above.
    From these results, the mode of spreading of the virus in leaf tissues and the local lesion formation are discussed.
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  • Masaya SHIRAISHI, Kazunori SAKAMOTO, Yasuji ASADA, Takashi NAGATANI, H ...
    1975 Volume 41 Issue 1 Pages 24-32
    Published: January 25, 1975
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Surface ultrastructure of conidia, germ tubes, appressoria and conidiophores of Peronospora parasitica, and of the diseased leaves (Raphnanus sativus) was observed by the scanning electron microscopy. Mature conidia were approximately 7×10μm in length. Most of appressoria were connected laterally with the germ tube. Appressoria and germ tubes had smooth surfaced structures. Penetration pegs can usually be found on the surface of the diseased region when materials were fixed 4 days after inoculation. Usually, cuticular penetration was observed, and stomatal infection was sometimes found. Conidiophore was formed through the stoma. In the early stages of conidiophore formation, no concave image was found in the basal region of the conidiophore, and then a contracted image was found in the region when the conidiophore developed. This seems to be caused by the mechanical pressure of stomatal guard cells. A wrinkled surface of young conidiophore was also observed. Conidia were formed directly from the swelling tips of the conidiophore, and they had the same surface structure as the conidiophore. Old conidia, however, had many wart-like structures, although the mature conidiophore had a smooth surface. Stomata on naturally infected leaves seem to expand more remarkably as compared with those of healthy ones. The surface of the diseased region also showed a crumpled image by exfoliation of wax and cuticular substance.
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  • Hitoshi KUNOH, Hiroshi ISHIZAKI, Fukukazu KONDO
    1975 Volume 41 Issue 1 Pages 33-39
    Published: January 25, 1975
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    The halo area on the barley leaf epidermis induced by powdery mildew infection was examined using a cotton blue stain and an electron probe microanalyzer. The halo consisted of the faintly stained zones and the densely stained zones which alternately encircled the penetration point, when stained with cotton blue. With the scanning electron microscope, two slightly raised zones, the central and the outer ring zones, were clearly distinguished in the halo. They corresponded to the zones stained faintly with cotton blue. The composition analysis by the X-ray microanalyzer indicated that calcium accumulated around the penetration point and manganese and silicon in the central and the outer ring zones.
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  • Yoritsugu ENDO, Hiroyuki TSUYAMA, Fusaji NAKATANI
    1975 Volume 41 Issue 1 Pages 40-48
    Published: January 25, 1975
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The production of antibacterial agents (AAs) by isolates of Erwinia carotovora, the properties and their activity spectra were studied. The bacterial cell inductively produced the AA, when irradiated with UV or treated with mitomycin C at their early exponential growth phase, corresponding to the lysis of bacterial cells observed during 3-5hrs of culture after the treatment. The AAs obtained from 5hrs cultures of each isolate after UV irradiation differed from each other in their activities. In the case of one isolate, however, the activity did not vary with the difference in the induction method. All of the 17 isolates were found to have the ability to produce the agents, which were classified tentatively into 4 groups according to the similarity of their activity spectrum. The agent produced by each isolate indicated that it cannot be reproduced in the cell of each indicator. The activity of AA was found to be maintained for at least 20 days at 4C; it was retained in dialized solution but was lost by heat treatment; and it was found in the precipitate obtained by salting out the lysate. UV absorption spectra of the partially purified preparation exhibited the highest absorption at 275nm and the lowest at 260nm. The AAs appeared to be protein characterized by a large molecule. It was concluded that AAs are a kind of bacteriocin.
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  • Toshio NAKAJIMA, Kohei TOMIYAMA, Masaru KINUKAWA
    1975 Volume 41 Issue 1 Pages 49-55
    Published: January 25, 1975
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Cut surface of potato tuber (R1-cultivar) was inoculated with an incompatible race of Phytophthora infestans. Then the slices prepared from the infected tissue were analyzed for their rishitin and lubimin content. Most of rishitin and lubimin was found in a zone in which the cells became brown with only a trace in the healthy tissue adjacent to the brown zone. However, the amount of lubimin was very low as compared with that of rishitin. In the inoculation fluid within the hole made in the tuber tissue, a large amount of rishitin and lubimin was found. In this case, lubimin was found in greater amount than rishitin during the early period of infection, but later the amount of rishitin exceeded that of lubimin. It was demonstrated by incorporation of acetate-2-14C into rishitin that rishitin was synthesized mostly in the adjacent healthy tissue which had not been invaded by the parasite. Rishitin synthesis was especially active in the first several healthy cell layers neighbouring the brown tissue. Since, at this time, hyphal development has already stopped, these cells were never invaded by the parasite and did never turn brown. Rishitin seemed not to be synthesized in the browned tissue. It is concluded that the rishitin sythesized in the adjacent healthy cells is transported to the brown cells and accumulates there. It also diffuses and accumulates outside the brown cells.
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  • Nobuaki MATSUYAMA
    1975 Volume 41 Issue 1 Pages 56-61
    Published: January 25, 1975
    Released: February 19, 2009
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    Ample supplies of nitrogen fertilizer in the form of ammonia reduced total carbohydrates, hemicellulose and lignin content of rice plant. There was a slight reduction of α-cellulose, but no alteration of pectic substances. Total sugar was increased according to the ammount of N supplied. At maximum level of total nitrogen in rice plant, the additional supply of nitrogen fertilizer had no effect on the reduction of hemicellulose. The hydrolysates of hemicellulose consist mainly of xylose with small quantities of arabinose and glucose. The significance of the reduction of cell-wall materials for reduced mechanical resistance to rice blast disease is discussed.
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  • Keisuke YOSHIDA, Kenji TAKAHASHI, Tadaoki INABA, Toshihiro KAJIWARA
    1975 Volume 41 Issue 1 Pages 62-66
    Published: January 25, 1975
    Released: April 03, 2009
    JOURNALS FREE ACCESS
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  • Hitoshi KUNOH, Tomonori SHIRAISHI
    1975 Volume 41 Issue 1 Pages 67-68
    Published: January 25, 1975
    Released: February 19, 2009
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  • Hiroharu TAKAHASHI, Tutomu FURUTA
    1975 Volume 41 Issue 1 Pages 69-72
    Published: January 25, 1975
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Surface structure of teliospores, development of basidia and the process of sporidia formation on Gymnosporangium haraeanum P. et H. Sydow were observed with scanning electron microscopy. Many wrinkles were observed on the surface of a basidium and sterigma according to their developmental stage.
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  • Tomomasa MISATO, Hachiro WAKAMATSU, Takao NATSUME, Akio YOSHIOKA, Kuni ...
    1975 Volume 41 Issue 1 Pages 73-76
    Published: January 25, 1975
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Takken MATUO, Akira MATSUDA, Katsumi OZAKI, Kijuro KATO
    1975 Volume 41 Issue 1 Pages 77-80
    Published: January 25, 1975
    Released: February 19, 2009
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  • 1975 Volume 41 Issue 1 Pages 81-88
    Published: January 25, 1975
    Released: February 19, 2009
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  • 1975 Volume 41 Issue 1 Pages 88-92
    Published: January 25, 1975
    Released: February 19, 2009
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  • 1975 Volume 41 Issue 1 Pages 92-109
    Published: January 25, 1975
    Released: February 19, 2009
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  • 1975 Volume 41 Issue 1 Pages 109-115
    Published: January 25, 1975
    Released: February 19, 2009
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  • 1975 Volume 41 Issue 1 Pages 116-122
    Published: January 25, 1975
    Released: February 19, 2009
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  • 1975 Volume 41 Issue 1 Pages 122-128
    Published: January 25, 1975
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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