This paper deals with the effect of several sugars to the germination and the germ-tube elongation of Puccinia coronata Corda, and the comparison of the kind and quantity of sugars present in uninfected oat varieties, Ferguson and Algerian, resistant and susceptible, respectively. The germination of uredospore was most strongly inhibited by glucose, xylose, and fructose, less strongly by sucrose, whereas, was not inhibited by soluble starch. The resistant variety contained much more amount of total and reducing sugars which were inhibitory to spore germination, than the susceptible variety. The content of pentose was higher in the susceptible variety than in the resistant, while that of hexose was higher in the resistant than the susceptible, the content of hexose being higher than that of pentose, and the content of aldose higher than that of ketose in both varieties. Among monosaccharides, the inhibitory effect for spore germination was high according to the following order: ketohexose>aldohexose>pentose. Considering that the content of aldohexose markedly differs between two varietis, this may be one of the cause of varietal difference in resistance.
Localization and translocation of tobacco masaic virus in the cells and tissues of the systemically infected young leaves of Nicotiana tabacum L. var. Xanthi was investigated by means of the fluorescent antibody technique. The specific staining resulting from the serological reaction between the virus antigen and its specific antiserum was found at first in both the palisade and spongy parenchyma tissues surrounding the peripheral portions of vascular bundles, and subsequently the antigen was detectable soon in the neighboring regions. The first change to be discerned in the infected cell as a result of the virus multiplication. was the formation of specifically stained small granules in cytoplasm, followed by their gradual enlargement, scattering by the protoplasmic streaming into reticulate arrangement of the antigen. At a later stage of virus multiplication, the viral antigen seemed to be concentrated around the unstained nucleus, where the specific staining was markedly intensified. The granules irregularly distributed in the cell seemed to lie in contact with chloroplasts but not near the nucleus. The tissue sections prepared from leaves showing typical mosaic symptoms were found by the staining technique to be composed of two distinct areas, clearly stained and unstained. Virus antigen was demonstrated in hair cells, epidermal cells, guard cells of the stomata, calcium-oxalate cells of the spongy parenchyma and also in the phloem.
The culture filtrate of Cochliobolus miyabeanus (Ito et Krib.) Drechs., the cauasl fungus of Helminthosporium leaf spot of rice plant, exhibited a strong ability for starch decomposition throughout the whole culture duration. Furthermore, the culture filtrate contained much residual sugar in the early stage of culture, namely, for the first 24 days after inoculation in this experiment. Because of those two characteristics of the filtrate, its inhibitory effect on β-amylase preparation was hardly detected. However, when the cultural filtrate was deproteinized by means of salting-out with ammonium sulfate, it revealed a striking inhibitory effect on the activity of β-amylase preparation, for starch decomposing ability was removed from the filtrate. From those results, it was concluded that certain kinds of inhibiting substances for starch decomposition were produced in the culture filtrate of this fungus.
Some compounds, which have an inhibitory effect on starch decomposition, are produced in the culture filtrate of Cochliobolus miyabeanus, the causal fungus of Helminthosporium leaf spot of rice plants. In this paper results on physico-chemical natures of the compounds were described. 1. These compounds are thermostable, and can not be extracted with ethylether, nor precipitated with 90 percent ethanol. They do not form chelate compounds with EDTA or citric acid, but are adsorbed with cation exchange resins. From these facts, it is evident that they are cations of low molecular weight, being neither protein, organic acid nor heavy metal. Consequently, they seem not to be any kinds of SH-inhibitors. 2. These compounds have only one peak of absorption spectrum at 310mμ. 3. These compounds have no relation with a brown color substance produced in the culture filtrate. 4. From the above results, it is assumed that the starch-decomposition-inhibiting substaces are some alkaline metabolites produced by the causal fungus, and that they are diffused from diseased lesions and inhibit β-amylase activity in the surrounding healthy tissues.
(1) Employing the chemically defined medium containing L-cystine, in which the growth environmental condition seems to be similar to that in the host plant at least as for the growth limiting factor, phenazine was found as a peculiar bacteriostatic agent having the wide range of partial growth inhibitory activity against Xanthomonas oryzae. (2) Regarding rice plant pot tests against the leaf blight disease in our phytotrone, phenazine showed a fairy high inhibitory value, dose at 200ppm was ca. 93% and dose at 150ppm was ca. 83%. (3) One aspect on the action mechanism of phenazine against the bacterium was elucidated, that is, phenazine seemed to be incorporated into the respiratory system of the bacterium and it formed the respiratory regulating system to suppress the rate of the respiration.
A virus was detected in apparently healthy carnation plants of Coral variety. It was proved to be transmissible by sap and also by Myzus persicae. By sap inoculation, it produced chlorotic or necrotic local lesions in Chenopodium album, and systemic mottling in Dianthus barbatus, D. nipponicus, and D. chinensis. The virus caused latent infection of carnation seedlings from true seeds. Such other plants as Nicotiana tabacum (var. Bright Yellow), N. glutinosa, N. debneyi, Vicia faba, Vigna sesquipedalis, Gomphrena globosa, and Beta vulgaris were not susceptible. The virus in the sap was inactivated in 10 minutes between 50°C and 60°C, and at room temperature between 6 and 9 days. Dilution-end-point was shown to lie between 1:1, 000 and 1:5, 000. When examined by electron microscope, the partially purified preparation showed the presence of slightly curved elongated particles of about 800mμ in length. The prepared antiserum showed relatively low titers against the homologous virus and did not react with potato virus S, whereas the S virus antiserum reacted with the present virus. From these results, it was concluded that the virus in question may be closely related to the carnation latent virus reported by Kassanis (1955) in England.
The writers studied on the change of chlorophyll content of rice plants spayed with 2, 4-dichloro-6-(orthochloroanilino)-1, 3, 5-s-triazine (Triazine, Dyrene). The rice plants were cultivated in soil without supplying fertilizers, and the chlorophyll content of the first, second, and third leaves from the top was measured 2, 4, and 8 days after spraying Triazine. In this experiment, there was no marked difference in the chlorophyll content between Triazine sprayed and control leaves. In the leaves of rice plants, cultivated with fertilizers, chlorophyll content was measured serially according to the leaf order from the top and days after spraying. Four days after the spraying chlorophyll-a increased in the descending order of sprayed plots: water, Triazine 2500ppm (high concentration) and 1250ppm (low concentration). Chlorophyll-b and the total amount of chlorophyll, however, rather showed a decreasing tendency in the sprayed plot of 2500ppm Triazine. Eight days after spraying, however, chlorophyll-a, -b, and total amount of chlorophyll increased in the leaves sprayed with Triazine. Summarizing these results, spraying Triazine upon leaves of rice plants seems to increase the content of chlorophyll-a and -b, but decrease chlorophyll-b when sprayed with high concentration of Triazine. The latter tendency, however, seems to diminish with the lapse of time.
The pathogenicities of 8 strains of Xanthomonas oryzae (Uyeda et Ishiyama) Dowson., which causes the bacterial leaf blight of rice plant were investigated by the method of pinbundle inoculation on leaves of rice seedlings. As a result, we confirmed that they showed various grades of pathogenic activity in every strain. The pathogenic coefficient differed from 13, 7 to 0. Next, the susceptibilities of the 8 strains to some antibiotics were studied by cup method, paper-disk method and agar streak-dilution method. Great difference was observed in the susceptibilities to streptomycin sulfate and dihydrostreptomycin sulfate but little difference was found in penicillin G potassium salt, cellocidin, Chloramphenicol and other 7 antibiotics regardless of their pathogenicities.