Japanese Journal of Phytopathology
Online ISSN : 1882-0484
Print ISSN : 0031-9473
ISSN-L : 0031-9473
Volume 38 , Issue 1
Showing 1-15 articles out of 15 articles from the selected issue
  • Mikio NOZU, Masaki YAMAMOTO
    1972 Volume 38 Issue 1 Pages 1-3
    Published: January 20, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Ultra-structure of the hypertrophied leaf-tissue of Camellia sasanqua Thunb. infected with Exobasidium gracile (Shirai) Sydow was observed by means of an electron-microscope. The results were shown in Figs. 1-13. Hyphae (H) were recognized in intercellular space (Figs. 3, 4), middle lamella (Figs. 5, 6, 9), cell wall (Figs. 7, 8) and on the surface (Figs. 1, 2) of the suscept tissue. As shown in Figs. 1 and 2, nucleus, nucleolus, vacuole and lipid-granules were observed in hyphal cell but those organelles were not found clearly in fine filamentous hyphae (Figs. 3-6). Cell wall and cytoplasmic layer of the suscept cell were invaginated (Figs. 7, 8) but haustorial structure was not observed. The writers considered that hypertrophy was caused by the pathogen before the invagination of the suscept cell wall. Low electron-dense substance was observed in the surrounding part of the hyphae in the suscept tissue (Figs. 1-4). Hypertrophied cell had a large vacuole (V) and thin peripheral layer of cytoplasm (Figs. 3-11) as shown in Fig. 10.
    Sometimes, high electron-dense material was recognized in vacuole of the suscept cell (Figs. 5, 6, 9, 11). Lamellar structures and osmiophilic granules were found but starch grains were not observed in the chloroplasts of the hypertrophied cell (Figs. 3, 4, 12, 13). Plasmolysis was not occured and cell membrane was adjacent to the cell wall of the suscept.
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  • G.S. SHEKHAWAT, D.N. SRIVASTAVA
    1972 Volume 38 Issue 1 Pages 4-6_1
    Published: January 20, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Inoculation of rice panicles with Xanthomonas translucens f. sp. oryzae (Fang et al.) Pordesimo (=X. oryzicola Fang et al.) at different developmental stages of florets and seeds, resulted in brown or black discolouration and death of ovary, stamens and endosperm, and browning of glumes. The bacterium was found to remain under the glumes in mature seed.
    Plumule got contaminated with the bacterium hibernating under the glumes, during seed germination. Infection of coleoptile, leaf sheaths and first leaf occurred successively through open, semi-open and normal types of stomata, respectively. The first leaf carried the bacterium to the aerial parts. Seed infection in panicles occurred from the bacterial exudates on the flag leaf.
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  • G.S. SHEKHAWAT, D.N. SRIVASTAVA
    1972 Volume 38 Issue 1 Pages 7-14
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Studies were conducted on the perpetuation and host range of the rice leaf streak pathogen Xanthomonas translucens f. sp. oryzae (Fang et al.) Pordesimo (=X. oryzicola Fang et al.) and the factors affecting the disease.
    Seeds from a diseased crop when sown newt season, developed diseased seedlings under field as well as laboratory conditions. The bacterium was isolated from these seedlings and its pathogenicity was confirmed. No diagnostic symptom attributable to bacterial infection was detected on such seeds, nor the bacterium could be isolated. The bacterium did not perpetuate in infected debris. Even in the leaves and bacterial beads stored under room conditions, the bacterium remainedviable upto 90 and 75 days respectively. The bacterium did not infect any of the 30 grasses, 8 cereals and millets including maize and 4 species of Cyperus.
    The young rice leaves were more susceptible to the disease, and became resistant with age. Two to three continuous days with high humidity (R.H. 83.0-89.5%) or dew during morning hours were necessary for infection. The lesion enlargement was favoured by moderate temperatures (26.1-30.5°C) and retarded at lower range (below 22.4°C), irrespective of relative humidity.
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  • Suesaku CHIBA, Jyunitsu CHIBA, Keise SHIMADA, Hiroshi KAGAWA
    1972 Volume 38 Issue 1 Pages 15-21
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Infection rate of blast fungus was estimated under various field conditions. It was calculated by the two equations, y=Y/(1+ke-rt) (logistic curve) and y=y0er(t-t2/2T), where y is the number of lesions, Y is the final number of lesions in the year, y0 is the number of lesions at the initial time of infection, r is infection rate, t is the time in days and T is the time when the increase of lesion number stopes. When the disease increase plotted with lesion numbers, the latter equation fitted better than the former one. Infection rate calculated by the latter equation showed a significant negative regression against the number of lesions at the first recording time, indicating the influence of density effect of pathogen multiplication.
    Infection rate was influenced more greatly by the amount of top dressed fertilizer and annual changes in climatic conditions than the other given factors, that is, transplanting time and variety of rice.
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  • V.K. GUPTA, S.P. RAYCHAUDHURI
    1972 Volume 38 Issue 1 Pages 22-24
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    Four compounds namely catechin, gallic acid, gallotannins and ellagic acid were tested for their inhibitory effect on potato virus Y (PVY) in vitro and in tissue culture. Catechin and gallotannins showed inhibition (39.5 and 48.1 percent) of PVY infectivity in vitro. The other two showed less inhibition. In in vivo studies, gallic acid and gallotannins showed more inhibition (67.5 and 66.7 percent) of virus multiplication in callus tissue growing in medium containing these two compounds. The other showed less inhibition.
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  • Tadaoki INABA, Toshihiro KAJIWARA
    1972 Volume 38 Issue 1 Pages 25-29
    Published: January 20, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Effect of light and darkness on hyphal growth of cucumber downy mildew fungus, Pseudoperonospora cubensis (Berk. et Curt.) Rostow., in the host tissue was examined anatomically. The effect was estimated by counting the number of hyphae which was observed in the stained paraffin section of infected tissue by a microscope. Hyphae and haustoria in the infected tissue kept in both light and dark condition, began to increase in number abruptly from 2 to 3 days after inoculation and continued to increase until 5 days. The hyphae and haustoria in dark condition, however, were about a half in number compared with those in light condition. Some differences of hyphal diameter in average were also observed between the two treatments. It was 5.4μ in lesion kept in light and 4.6μ in darkness. It is speculated that such decrease in hyphal density and diameter in darkness may affect the suppression of lesion development by the dark treatment for the infected cucumber leaves as reported in the previous paper.
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  • Shigehisa KIYOSAWA
    1972 Volume 38 Issue 1 Pages 30-40
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    The data during 1938-1949 on cumulative spore numbers of Pyricularia oryzae at Toyoshina, Nagano Prefecture were analyzed by using 3 equations,
    y=Y/1+ke-rt (1), y=Y'/1+ke-rt (2) and y=y0er(t-t2/2T) (3).
    The cumulative spore curve fits best equation (1), and least equation (2). Equation (1) cannot, however, be used for forecasting epidemic development. Equation (3) is generally a useful model for forecast of blast disease. The analysis of the data by equation (3) showed that the disease increase measured by cumulative spores is divided into two phases: one has higher multiplication rate and the other a lower rate. A method of forecast of disease epidemics by equation y=y0ert was proposed.
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  • Shigehisa KIYOSAWA, Masae SHIYOMI
    1972 Volume 38 Issue 1 Pages 41-51
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    In order to examine the effectiveness of use of multiline variety system, simulations of disease increase in the pure stand of susceptible variety and in the mixed stand of susceptible and resistant varieties were made by following the dispersal nature of pathogens.
    Dispersal distributions of various pathogens were confirmed to fit the equation y=βe-αd, where y is the number of spores or lesions on a plant, d is distance in meter, and α and β are constant for dispersal gradient and the number of lesions on the source plants, respectively.
    When the distance between plants is taken as a unit of distance, if α is less than 0.2 the effect to prevent the disease increase of mixture of resistant plants in susceptible population at a rate of 1:1 can be expressed by the Leonard's equation, y'/y0=mn×(y/y0). The effect of mixing resistant plants decreases in α values over 0.2.
    Double or multiple infection and the decrease of healthy area of susceptible plants are presumed to play an important role in flattening of dispersal distribution curve in the actual field as well as contamination from outside sources and the increase of infection generation as pointed out by Cammack.
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  • Shigehisa KIYOSAWA
    1972 Volume 38 Issue 1 Pages 52-59
    Published: January 20, 1972
    Released: February 19, 2009
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    The mixture and rotation cultivations of resistant varieties were theoretically compared as to which more effective usage is for controlling plant disease. They were compared under the standard conditions where yearly increase of lesions of a fungus strain on a given variety at the initial time of infection in a year is according to dy/dτ=yλ, therefore y=y0eλτ. A relation between the longevity of rotation cultivation (T) and that of mixture cultivation (T') of given varieties (v) is given by the equation T/T'=vλc'c, where λc and λc' are the rate of increase of lesions under both cultivations, under given conditions.
    Secondly, a relationship between daily rate (r) and yearly rate (λ) of disease increase was studied. When the daily increase of disease is according to the equation y=y0ert or y=y0er(t-t2/2T), their relationship is given by rtE+logeθ=λ or r(T/2)+logeθ=λ, where tE or T is the terminal stage of infection in a year respectively and θ is the rate of overwintering.
    It was emphasized that the nature of daily increase of disease is necessary to be analyzed especially in relation to the presence or absence of density effect, in order to know the relationship.
    The data on cumulative spore numbers at Toyoshina, Nagano Prefecture show that there is no or a little density effect in disease increase at that conditions.
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  • Mitsuya TSUDA, Akinori UEYAMA, Masuo NAKANO, Yasuhiko FUJINO
    1972 Volume 38 Issue 1 Pages 60-67
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    This paper discusses the lipid of Helminthosporium oryzae and its fatty acid components. The total lipid was fractionated on a silicic acid column into nonpolar lipid (NL) and polar lipid (PL), by eluting first with chloroform and then methanol. NL accounted for over 80% of the total lipid. The principal component of NL was triglyceride. PL was principally composed of ceramidemonohexoside (CMH), phosphatidylcholine (PC), phosphatidylethanolamine (PE) and unidentified lipids. The main fatty acid components of H. oryzae were C16:0, C18:0, C18:1 and C18:2.
    The existence of CMH in the PL fraction has not been reported previously in plant pathogenic fungi.
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  • H.E. KAUFFMAN, R.S.K.V.S. PANTULU
    1972 Volume 38 Issue 1 Pages 68-74
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    One hundred sixty one isolates of Xanthomonas oryzae from 38 rice growing areas of India were tested for their virulence reaction on 4 differential rice varieties, and their lysotype reaction against 7 isolates of the bacteriophage. BJ 1 possessed the broadest spectrum of resistance to the isolates followed by Malagkit Sungsong, and Early Prolific. Taichung (Native) 1 was susceptible to all except 2 isolates. Considerable variation in virulence was demonstrated among the isolates, but there was no evidence for the existence of races. Variation in lysotype reaction to the bacteriophages was extensive.
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  • Toru SHIMOMURA
    1972 Volume 38 Issue 1 Pages 75-80
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
    When Nicotiana glutinosa or N. tabacum Xanthi nc was inoculated with TMV on its lower leaves and was kept at 22°C, TMV did not move from the inoculated leaves to the upper parts of the plant through inner stem tissues. When the plant was kept at 30°C after inoculation, however, TMV rapidly moved from the inoculated leaves to other parts of the plant, and the plant became systemically infected, developing symptoms on the top leaves 1 week after inoculation.
    Contrary to this, when the plant that had been kept at 22°C for a long time enough to develop necrotic lesions on the inoculated lower leaves, was transferred to 30°C, usually no systemic infection occurred, even after 2 weeks or more of incubation at 30°C. In this case, TMV could be detected abundantly in the apparently intact tissues surrounding the leaf lesions, but no virus could be detected in the tissues of upper parts of the plant.
    This finding suggests that the movement of TMV from inoculated leaves on which local lesions have fully developed is somehow hindered in the midrib or the petiole of the inoculated leaves. Deposition of callose in the tissues of midrib and petiole of inoculated leaves was observed, using anilin-blue staining and fluorescence microscopy, and it was found that there is a positive correlation between the callose deposition in these tissues and the restriction of the movement of TMV from the inoculated leaves to other plant parts.
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  • Pi TSAI, Akira SHINKAI, Hideo MUKOO, Shigemasa NAKAMURA
    1972 Volume 38 Issue 1 Pages 81-85
    Published: January 20, 1972
    Released: April 03, 2009
    JOURNALS FREE ACCESS
    Healthy sweet potato and morning glory plants were inoculated by feeding with infective leafhoppers, Orosius ryukyuensis, on each plant. The infected plants were examined by electron microscope. In the sweet potato plants, no mycoplasma-like organism (MLO) was observed before the appearance of initial symptoms, but as soon as the initial symptoms appeared, many branched filamentous form and bacilliform MLO were observed. In the phloem cells of sweet potato and morning glory plants which showed typical symptoms, numerous MLO ranging between 75 to 1, 400mμ in size were observed. In the morphology and distribution of MLO, there was no difference between both hosts. There appeared to be some differences in the morphology of MLO found in different plant parts: leaf vein, pedicel, stem, petal, and root. In mature phloem cells, MLO were often found crowded along the cell membrane. In immature phloem cells adjacent to apical meristem of stem, and petal, possible reproductive forms of MLO were observed in the cytoplasm. MLO were frequently found within sieve pores, suggesting that MLO might move through these pores. In the phloem cells of diseased plants, numerous large multivesicular bodies were frequently observed. In the vacuoles of these cells, high density of the square crystals varying in size from 0.1 to 2μ were also frequently observed.
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  • Yuichi MIYAMOTO, Yoshimiki AMEMIYA
    1972 Volume 38 Issue 1 Pages 86-87
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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  • Kazuto YAMADA, Toshihiro KAJIWARA, Shigeru OZOE
    1972 Volume 38 Issue 1 Pages 88-89
    Published: January 20, 1972
    Released: February 19, 2009
    JOURNALS FREE ACCESS
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