Masuro Yamaguchi

Nitrogen-fixing microorganisms in paddy soils: VI

Abstract In the preceeding paper (1), it was reported that when R. capsulatus is mixed with B. subtilis, in spite of no nitrogen fixation in separate cultures, by using a glycerol or starch medium, the combination was able to fix molecular nitrogen and it seems that there is a correlation between the production of pyruvic acid and the nitrogen fixation in the mixed culture.

NITROGEN-FIXING MICROORGANISMS IN PADDY SOILS : V. : Nitrogen Fixation in Mixed Culture of Photosynthetic Bacteria (Rhodopseudomonas capsulatus species) with Other Heterotrophic Bacteria (1)

Abstract P. W. WILSON (1) reported that the contaminated culture of azotobacter was superior to the pure culture in the fixation of nitrogen. We (2) also reported that the nitrogen fixation by photosynthetic bacteria, Rhodopseudomonas capsulatus associated with various microorganisms was superior to that in the pure culture.

Nitrogen-fixing microorganisms in paddy soils (Part 2) distribution of blue-green algae in paddy soils and the relationship between the growth of them and soil properties

Abstract As was shown in the previous reportl), a close connection between the photosynthetic autotrophs and nitrogen fixation in paddy soils was demonstrated.

NITROGEN-FIXING MICROORGANISMS IN PADDY SOILS : (PART 3) DISTRIBUTION OF NON-SULPHUR PURPLE BACTERIA IN PADDY SOILS

Abstract The possible significance of blue-green algae in the nitrogen economy of paddy soil has been pointed out by many investigators.

Nitrogen-fixing microorganisms in paddy soils (Part 1) Characteristics of the nitrogen fixation in paddy soils

Abstract In most paddy soils, as is already well-known, the crop yield goes on decreasing just for the first few years and then stabilizes at a comparatively high level with no supply of fertilizer or manure.

NITROGEN-FIXING MICROORGANISMS IN PADDY SOILS IV. : Nitrogen Fixation by Photosynthetic Bacteria (Rhodopseudomonas capsulatus species) under Various Conditions

Abstract In 1949, GEST and KAMEN (1,2) reported that Photosynthetic bacteria can fix molecular nitrogen. LINDSTROM et al. (3,4) tested the nitrogen fixing ability of five species of photosynthetic bacteria under the following four conditions; 1) anaerobic light, 2) aerobic light, 3) aerobic dark, 4) anaerobic dark. As the result of the experiment, they certified that it Was only under the anaerobic light condition that the bacteria can fix molecular nitrogen.

Occurrence of Curtobacterium sp. possessing ?-cyclohexyl fatty acids in soil with zinc added

A bacterial strain, Curtobacterium sp., isolated from a soil with zinc added possessed ω-cyclohexyl fatty acids. ω-Cyclohexyl undecanoic acid made up 47% of the total fatty acids; it was the most abundant fatty acid in the strain grown in tryptone medium. 12-Methyl tetradecanoic acid (23%) and 14-methyl hexadecanoic acid (22%) were also major fatty acids. The proportion of ω-cyclohexyl undecanoic acid increased as the pH of the medium decreased and as the culture temperature increased.The bacteria grew almost normally in zinc-enriched medium, and ω-cyclohexyl undecanoic acid increased with zinc concentration. Zinc added to the medium was not abundant in the cell fraction, and the ratio of increase of zinc in the cells was not so high as in the culture medium. These results suggested that ω-cyclohexyl fatty acids are related to the zinc tolerance of the isolated strain, and that this tolerance depends on low permeability of the membrane to zinc.

Studies on a red-colored soil derived from basaltic andesite of Shibayama

Abstract In the preceding papers (1, 2), the specificities of Shibayama red soil clarified by chemical and mineralogical studies were described.

Decrease in the proportion of cells capable of inducing nodules to the population of Rhizobium japonicum introduced into soil

Spontaneous mutant of Rhizobium japonicum 3l1b-138, which was resistant to both 100 µg rifampicin and 100 µg nalidixic acid per ml, was introduced into air-dried soil at the density of 108 cells per g of dry soil. The ability of the soil to induce nodulation in soybean declined during the incubation. The soil lost its nodulation ability after 2 weeks of incubation at 40°C. Viable count of the rhizobia decreased to 1 × 105 or 2 × 105 cells per g of dry soil after 4 weeks of incubation of the soil at 30°C or 40°C, respectively. About 50 colonies were randomly picked up from the nutrient agar plates, and were examined for their nodulation ability. The proportion of cells capable of inducing nodules (Nod+) to the population of Rhizobium decreased with the incubation of the soil. There were no Nod+ after 20 days of incubation at 40°C. These results suggest that the proportion of Nod+ to the population of Rhizobium plays a more important role in the development of nodules than the population size. Key Words: mi...

Studies on a red-colored soil derived from basaltic andesite of Shibayama V. An introduction of techniques of rock magnetism

Abstract Some techniques of rock magnetism were tried to apply to deduce alteringtemperature of the red altered andesite rocks of Shibayama, Yashima, and Kiyama from which the specific chocolate red colored soils had been formed. Interpreting the Jn-ΔJt plots acquired by THELLIERs graduate heating method together with the results of thermomagnetic and X-ray diffraction analyses, it was Indicated that the red rocks had been formed by alteration at the temperature of 450–500°c or otherwise at higher than Curie temperature. Thus, the red altered rock specimens among which no distinct differences was noticed showed the possibility of suffering the different process or degree of alteration. Though further study especially on the oxidation state at alteration may be indispensable, fairly definite Interpretation for the process of rock weathering or soil formation could be done by Introduction of some techniques of rock magnetism. Based on the results of the studies hitherto carried out, the authors can conclud...