Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 35 , Issue 1
Showing 1-16 articles out of 16 articles from the selected issue
  • Toshikazu TANI, Hiroaki NANBA
    1969 Volume 35 Issue 1 Pages 1-9
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Each of ten isolates of Botrytis cinerea used in this study produced three kinds of macerating activities, which have been designated in this paper as M-I, M-II, and M-III. M-I and M-II were active on potato tubers and had respective pH optima at about 2.7 and 5.5. M-III, having a pH optimum near 4.5, degraded mitsumata inner barks but did not macerate potato tubers.
    Production of three macerating activities was found to be constitutive throughout all growth phases of mycelia. on cultures with some isolates, M-II ahd M-III disappeared when pH of the culture solution decreased to 2.5. This was attributed to inactivation of M-II and M-III at low pH.
    Isolate R-2, the most potent producer of macerating enzymes among the isolates used, produced on peptone-salts solutions a pectin esterase (opt. pH 5.0), endo-polymethyl-galacturonases (opt. pH 3.5 and 4.3), endo-polygalacturonases (opt. pH 4.3 and 5.5), exo-polygaiacturonases (opt. pH 4.3 and 5.5), and cellulases Cx (opt. pH 4.5 and 6.5). No trans-eliminase activity for pectin and pectic acid was detected in cultures on the solution either with or without pectin.
    Zone electrophoretic study indicated that M-I and M-II were composed of three and two components, respectively.
    A qualitative comparison of macerating and related enzyme activities described in the literature and in the present study was made.
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  • Kei ARAI, Yoji DOI, Kiyoshi YORA, Hidefumi ASUYAMA
    1969 Volume 35 Issue 1 Pages 10-15
    Published: January 25, 1969
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Ultrathin sections of affected leaves from plants of Physalis floridana Rydb., Datura stramonium L. and Solonum tuberosum L. cultivar Danshaku, infected with potato leafroll virus respectively, were prepared for electron microscopy. Examination of the sections revealed uniform particles, spherical with a diameter of approximately 24mμ, in the phloem tissue of all 3 hosts. These particles were observed within the ground cytoplasm or vacuoles in the phloem companion cells, phloem parenchyma cells and young xylem vessel, but not in the mesophyll cells. In the phloem companion cells of Physalis plant, the particles often occurred in great abundance within the cytoplasm, apparently causing necrosis of the cell. In the vacuoles, the particles generally formed amorphous aggrega tes and sometimes crystalline aggregates. Similar particles were never found in healthy plants. The procedure adopted for partial purification of the virus involved homogenation of infected leaves in 0.5M phosphate buffer pH 6.5, chloroform clarification, and differential centrifugation. The resulting preparations from all 3 hosts were found to contain spherical, probably polyhedral, particles approximately 25mμ in diameter. Infectivity of the preparations was demonstrated not only by injected aphid transmission, but also by mechanical inoculation into test plants by means of needle-prick method. The evidence seems to indicate that these spherical or polyhedral particles with a diameter of approximately 25mμ are the potato leafroll virus.
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  • Shigeyasu AKAI, Masaya SHIRAISHI, Yasuji ASADA, Masao FUKUTOMI
    1969 Volume 35 Issue 1 Pages 16-20_3
    Published: January 25, 1969
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    The present paper is a result of histological and histochemical observations of the oleocellosis-like spot disease appearing on fruits of Iyo-orange (Citrus iyo Hort. ex Tanaka).
    The peel of healthy area of fruits is composed of epicarp (epidermis), mesocarp and endocarp. The mesocarp comprises hypodermis, flavedo and albedo tissues. The degenerated stoma in epidermis, oil glands and vascular bundles in the flavedo tissue were recognized.
    In oleocellosis type spot area, at first tangentially elongated cells developed in the flavedo tissue and then these cells died, leading to a necrotic degeneration. The cells in the flavedo tissue surrounding this area then began to divide periclinally. The necrotic cell wall gave a positive phloroglucinol-HCl reaction for the detection of lignin.
    In the area of reddish-brown concave type spots, the necrotic degeneration was more extensive than in the oleocellosis type spot. In case of the convex spots (scab-like) phellem developed remarkably under the necrotic cells and the spots raised as the result of abnormal division of phellogen and the formation of abnormal meristem.
    These observations suggested that all the types of spots are merely the representative of symptoms recognizable in the developmental process of identical disease, the oleocellosis-like spot, although the causal agent of this disease has not so far been elucidated.
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  • Akikazu HIRASHIMA, Tokuzo HIRAI
    1969 Volume 35 Issue 1 Pages 21-24
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    32P-labeled TMV was inoculated onto tobacco leaves. At times after inoculation, the leaves were homogenized and the homogenate was fractionated into precipitates of 600g centrifugation (P1), of 15, 000g centrifugation (P2), of 105, 000g centrifugation (P3), and acid-insoluble (P4), acid-soluble (S) fractions of the supernatant. The radioactivity in P3 fraction increased and that in P1 fraction decreased until 6 hours after inoculation, then the former decreased while the latter increased. RNase treatment of the homogenate showed the same radioactive distribution among fractions as that in nontreatment. The radioactivity in S fraction, though the amount was small, was higher during 6 hours after inoculation than that of later stages. The fate of TMV immediately after the introduction into host cells is discussed.
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  • Akikazu HIRASHIMA, Tokuzo HIRAI
    1969 Volume 35 Issue 1 Pages 25-28
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The precipitate of 105, 000g centrifugation (P3 fraction) obtained from the homogenate of tobacco leaves inoculated with 32P-labeled TMV was analyzed by the sucrose density gradient centrifugation. In addition to TMV peak, one or two shoulders appeared in the density gradient patterns and these shoulders became distinct and formed a peak with the progress of infection, particularly 6 hours after inoculation. RNase treatment of the homogenate and the density gradient patterns shown by the inoculation with 35S-labeled TMV revealed the protein nature of these peaks and shoulders. Control experiments confirmed the validity of this density gradient profile. Dissociation of one part, at least, of TMV coat protein immediately after the infection of tobacco leaves is discussed.
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  • Toshio KIKUMOTO, Masayuki SAKAMOTO
    1969 Volume 35 Issue 1 Pages 29-35
    Published: January 25, 1969
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Seeds of 22 plant species including host plants for Erwinia aroideae were used. Immediately after inoculation of E. aroideae to air-dried soil, surface-sterilized seeds were sown in this moist soil, and grown under field conditions. The seeds germinated within a week, and during this period the introduced pathogen predominated in this soil. From thirty-two days after seeding, rhizosphere populations of the growing plants were examined periodically by dilution plating and immunofluorescent staining.
    E. aroideae was recovered from the rhizosphere of only three plants, i.e. chinese cabbage, cucumber and morning-glory, in 3 cases of 52 tested, using the dilution plate method (Table 2). Immuofluorescent staining revealed survival of E. aroideae in the rhizospheres of chinese cabbage, radish, wheat, oat, red bean, tomato, cucumber, sponge-gourd, and morning-glory (Table 2 and Plate). On the contrary E. aroideae was detected consistently in the control soil during the experimental period by dilution plating using modified Drigalski's medium (Table 1).
    These results suggest that growing plants, including host plant, at least in early stages of growth can not effectively support the growth of E. aroideae and perhaps hasten the death of the pathogen through the intense microbial competition around the roots.
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  • Toshio KIKUMOTO, Masayuki SAKAMOTO
    1969 Volume 35 Issue 1 Pages 36-40
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Thirty species of crop plants belonging to ten families were grown in the field. On the 67th and 82nd days after seeding, the rhizosphere populations of each plant were analized by the dilution plate method and the enrichment technique using a selective medium.
    Bitaminna (Brassica sp.) and one variety of turnip had already been infected by soft rot disease before examination. The preferential stimulation of the soft-rot bacteria (Erwinia sp.) was observed in the following crops; Chinese cabbage, three varieties of Brassica chinensis L., teosinte, Chinese chives and tomato. No similar effect was noted with all the seven species of leguminous crop plants.
    Furthermore, fifteen species of weeds which grew naturally in the field where chinese cabbages were grown were tested. The selective action on the soft-rot bacteria was also demonstrated with cow-thistle, pigweed and spiderwort.
    Of the plants tested, the preferential effect on the soft-rot bactoria was most pronounced with the crops belonging to the cruciferous plants.
    It seems that the soft-rot bacteria are one member of the specific rhizosphere microflora in some of the cruciferous plants.
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  • Keiichi TOMARU, Tsugio SHIROYA, Yoichi TAKANAMI
    1969 Volume 35 Issue 1 Pages 41-46
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The purpose of this study is to find the changes in polyphenoloxidase (PPO) activity in cucumber mosaic virus (CMV) infected tobacco leaves at various periods after inoculation, and to find the effect of this enzyme on the changes in symptoms and virus concentration in vivo, which have been described in previous reports.
    Lower two leaves of tobacco seedlings (Nicotiana tabacunm L. cultivar Bright Yellow) were inoculated with ordinary strain of CMV (CMV-O), in an air-conditioned glasshouse at 25°C. PPO activity in the systemically infected upper three leaves was measured by the rapid method described by Shiroya, at weekly interval for 4 weeks after inoculation. Chlorogenic aid was used as the substrate of PPO reaction. PPO activity in the leaves increased from the 8th day to the 21st day after inoculation, and on the 14th and the 21st day the activities were significantly higher than those in healthy control leaves. On the 21st day, the difference of activities between infected and healthy leaves was highest, and reached 2.5 times on the basis of tissue dry weight. On the 28th day the enzyme activity decreased to the same level as on the 8th day (Fig. 2). These changes in enzyme activity were inversely proportional to the changes in symptoms and virus concentration in vivo.
    PPO activity in leaf extracts of tobacco plant grown in copper-deficient culture solution is known to decrease to about 1/10-1/25 of control non-deficient leaves, even when the sign of deficiency is not apparent. Tobacco plants were grown in Cu-deficient cuture solution prepared principally by the method of Staut and Arnon and inoculated with CMV-O. About two weeks after inoculation, greyish brown spots appeared on the lower leaves, as a sign of deficiency. During 4 weeks after inoculation, top leaves were harvested at weekly intervals, and homogenized with phosphate buffer (0.1M, pH 7.0) containing 1/30M Na-diethyldithiocarbamate. Infectivity in Cu-deficient and non-deficient leaves was compared by inoculation onto opposite primary leaves of cowpea. Changes in infectivity of Cu-dificient leaves were similar to those of non-deficient leaves (Fig. 5). Very low infectivity and masking of symptoms in newly developed leaves were obtained on the 21st day, even in Cu-deficient plants. The results were confirmed by using standard inoculum of vacuum-freeze dried infected leaf tissues and by serological assay.
    When Cu-deficient leaves were homogenized with purified yellow strain of CMV, the infectivity was 2.5-5 times higher than that of control inoculum with non-deficient leaves. In homogenate of Cu-deficient leaves, browning of sap was hardly detectable, whereas the non-deficient leaf sap showed strong browning. These results seem to indicate that deficient leaves has very low PPO activity, in agreement with Shiroya's previous finding.
    It appears that PPO is not directly responsible for the changes in symptoms and CMV concentration in vivo.
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  • Hidehiro HORIO, Isao YANO, Kazuo ESUMI
    1969 Volume 35 Issue 1 Pages 47-54_2
    Published: January 25, 1969
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    A virus was isolated from apparently healthy plants of potato varieties, USDA seedling 41956 and Kintoki-imo. The virus was transmitted by sap, but not by aphids so far as the present study concerned. By sap inoculation, it produced ring-like local lesions on the inoculated leaves of Nicotiana debneyi, while it caused systemic infection without symptoms in tomato and egg plant. Other plants such as Solanum demissum, S. villosum, Chenopodium amaranticolor, C. capitatum, C. murale, and Gomphrena globosa were also susceptible to the virus. Several potato varieties also became infected systemically.
    The virus was inactivated in 10 minutes between 65 and 70°C, and between 2 and 3 days, at room temperature (ca. 20°C). Dilution end point was shown to lie between 1:5, 000 and 1:10, 000. In electron microscopy using direct negative staining method devised by Doi et al. (1965), elongated particles of about 650mμ were observed. The virus was identified with potato virus M (PVM), because of its similarity to the description of PVM by Bagnall et al. (1956) in host range, mode of transmission, symptomatology, physical properties, and particle morphology. Antisera against PVM and PVS (potato virus S) were prepared by intravenous injections of rabbits with partially purified virus preparations. The antiserum against PVM was shown to have a homologous titre of 1:256 in precipitation test, and to be applicable to slide flocculation test. Result of cross precipitation tests between PVM-antiserum and PVS, and vice versa, showed some serological relationship between PVM and PVS. In the potato varieties Norin No.1, Oojiro, and Kennebec, mild to severe symptoms were observed on field-grown plants, naturally infected with PVM. The characteristic symptoms associated with PVM were of veinal streak, glossy appearance of leaf surface, crinkling, and downward curling of leaflets. Percentages of infection by PVM in seed potatoes maintained by the Tsumagoi National Potato Foundation Seed Farm were 11% in Norin No.1, 50% in Oojiro, 14% in Kennebec, 31% in Danshaku-imo, and almost 100% in Saco, USDA seedling 41956, and Kintoki-imo variety, respectively. With an exception of Norin No.1, these varieties were often symptomless carriers of PVM under field conditions.
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  • Kiichi KATSURA, Makoto ISAKA, Mitsuru MIYAGOSHI
    1969 Volume 35 Issue 1 Pages 55-61
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The bulb rot and leaf blight of scallion, Allium bakeri Regel, is one of the most serious problems in scallion cultivation in Fukui and Kyoto Prefectures, as it occurs in many places, especially in the season of low temperature, between September and April.
    The causal fungus was identified as a soil fungus, Phytophthora porri Foister, which is known as leek fungus in England and Holland. This fungus causes the white tip of the leaf, leaf blight, bulb rot and root rot of scallion in the field and storage.
    Bacteria and Fusaria, which had already been reported by some investigators as the causal microorganisms of the bulb rot of scallion in storage, seemed to be of secondary importance in most cases.
    In the field, the disease occurs with the appearance of white tip or blight of leaves after the rains in mid-autumn. The symptom is then extended to the bulb and root, resulting in the soft rot of the bulb. Direct infection of bulb and root is also frequently observed in the field, which is directly responsible for the patches often observed in scallion fields.
    Sporangia of this fungus are formed in abundance when the diseased leaves are either kept wet by rain or dew or dipped in water. The sporangia are long ellipsoid or obpyriform in shape, and mostly 24.7-57.7×16.6-39.2μ (36.5×25.2μ on the average) in size. Sexual organs are produced abundantly in unpaired cultures on agar media. Antheridia are mostly paragynous and rarely amphigynous. Oospores are spherical, yellowish brown, and 18.0-36.7μ (29.3μ on the average) in size. No chlamydospore is observed. The fungus is capable of growing in the temperature range of 0-27°C, the optimum being in the range of 15-20°C.
    The host range of this fungus was found to be as follows: scallion (Allium bakeri Regel), Welsh onion, onion, gynmight (Allium tuberosum Rattler), garlic, and wild rocambole (Allium nipponicum Franch. et Say.).
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  • Hirotaka TORIKATA, Masanori OHKAWA, Takeshi SASSA, Tetsuya YAMADA, Hir ...
    1969 Volume 35 Issue 1 Pages 62-66_1
    Published: January 25, 1969
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Alternaria kikuchiana TANAKA is specifically pathogenic to a few Japanese pear varieties such as Nijusseiki and Hakata-Ao causing the black spot disease, whereas it is weakly-or non-pathogenic to most of the Japanese pear varieties including Chojuro and Kikusui. It has already been reported that the fungus produces a toxin which is selectively toxic to the susceptible variety, the chemical nature of which is yet unknown.
    The present paper deals with the identification of two toxic substances isolated from the mycelial mat and culture filtrate of the fungus and their toxicity to both susceptible and resistant varieties.
    After the fungus was cultured on potato medium containing 2% sucrose for 18 days at 25-28°C, the dried mycelium was extracted with ether to give two compounds, which were also obtained from the cultural filtrate by chloroform extraction. By chemical and phyeical properties and by comparison with the authentic specimens kindly furnished by Dr. H. Raistrick, the compounds were identified as alternariol and its monomethyl ether. While the former was found inactive to the young leaves of Japanese pear, the latter caused round necrotic lesions to the young leaves of both the resistant and susceptible varieties. The acid (VIII) and phenol (IX) obtained from alternariol dimethyl ether by alkaline hydrolysis showed activity to the both varieties. These results indicate that both substances are not responsible for the selective toxicity of the fungus to the susceptible variety.
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  • Mitsuya TSUDA, Hiroshi EGAWA, Akinori UEYAMA
    1969 Volume 35 Issue 1 Pages 67-70
    Published: January 25, 1969
    Released: February 19, 2009
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  • Hiroyuki IEKI
    1969 Volume 35 Issue 1 Pages 71-75
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Antagonistic actions of Trichoderma spp. to Rosellinia necatrix and Helicobasidium mompa on PDA medium were determined for 16 isolates obtained from various districts of Japan.
    1. All of 16 isolates of Trichoderma spp. tested showed antagonistic action of Rosellinia necatrix, but among them there was a difference in antagonistic action to the causal fungus.
    2. Most of isolates of Trichoderma spp. showed antagonistic action to Helicobasidium mompa, but a few of them did not show any antagonistic action of Helicobasidium mompa.
    3. One isolate of Trichoderma spp. (T-13) showed the most active antagonistic action to both Rosellinia necatrix and Helicobasidium mompa.
    4. Generally speaking, antagonistic actions of Trichoderma isolates were more active to Rosellinia necatrix than to Helicobasidium mompa.
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  • Hiroyuki IEKI, Yasue KUBOMURA, Setsumi ITOI
    1969 Volume 35 Issue 1 Pages 76-81
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Detection and vertical distribution survey of the white root-rot fungus, Rosellinia necatrix (Hart.) Berl. were conducted in four forest soils in Hyogo and Kyoto Prefectures. These forests are located adjacent to mulberry fields which had been established on newly opened forests and the mulberry trees are sufferring from the white root rot disease. Whether the fungus was present or not in the forest soils was tested by examining the typical mycelium strands adhering to plant remnants and also by baiting method. In the latter method, bundles of mulberry and copse twigs, 30cm long, were buried to the depth of 20cm, and after a month or two the bundles were removed and examined for the colonization of the fungus. Under forest conditions, the fungus grows and survives saprophytically on partially decomposed plant debris in the F-, H-, and A1-layeres. The fungus inhabits to depths of one to five cm from the top of A-layer. In cases where the A-layer developed well into a thick layer, the fungus grew densely throughout the A1-layer; on the contrary, in cases where the A-layer developed only faintly, the fungus appeared in F- and H- layers and the amount of mycelial strands remained small.
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  • Mitsuya TSUDA, Hiroshi EGAWA, Akinori UEYAMA
    1969 Volume 35 Issue 1 Pages 81-84
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
  • Natsuki NISHIHARA
    1969 Volume 35 Issue 1 Pages 84-89
    Published: January 25, 1969
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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