Soil Microorganisms

[title in Japanese]

S. Kanazawa

Article type: Article
2001 Volume 55 Issue 1 Pages 1-2
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_1

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Effect of chromium on some enzyme activities in the wheat rhizosphere

Neng-Chang Chen, Shinjiro Kanazawa, Tsuyoshi Horiguchi

Article type: Article
2001 Volume 55 Issue 1 Pages 3-10
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_3

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We investigated the effect of Cr(Vl) on the rhizosphere enzymes of wheat seedlings by using the rhizobox setup developed by Youssef and Chino (1988). In this system, 20 mg Cr(Vl) kg^<-1> soil as K_2Cr_2O_7 was placed in several compartments separated from each other by a 500 mesh nylon cloth. Wheat seedlings were transplanted, was placed in a growth chamber under 33.6 μ mol m^<-2> S^<-1> light and 24/20℃ day/night, for one month. Plant growth, plant height, total root weight, total shoot weight and number of total tillers were lower, but the root/shoot ratio was higher in the Cr treatment than in the control, indicating that the addition of Cr(Vl) exerted an adverse effect on plant growth, especially on roots. There was a decrease in the pH across the rhizosphere within a range of 5 mm wide from the rhizoplane, which was most pronounced in the central compartment (C.C.) in both the control (1.25 unit) and Cr treatment (1.86 unit), i.e. the Cr treatment further decreased the pH (0.61 unit) within a range of 2 mm from the rhizoplane. Phosphomonoesterase, phosphodiesterase, exocellulase and β-glucosidase activities were much higher in the C.C. with a negligible or no rhizospheric effect in other compartments both in the control and Cr treatment. However, the Cr treatment enhanced the activities of exocellulase and β-glucosidase, but decreased the activities of phosphomonoesterase and phosphodiesterase in the C.C. The findings obtained in the current studies was analyzed in terms of possible application to the development of phytoremediation technology.

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Analysis of transcriptional region found in a tomato pathotype-specific DNA fragment of Verticillium dahliae

Toshiyuki Usami, Yoshimiki Amemiya, Masahiro Shishido

Article type: Article
2001 Volume 55 Issue 1 Pages 11-20
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_11

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The DNA fragment (VDf130) specific to the tomato pathotype of Verticillium dahliae, cloned from the genomic DNA of the fungal isolate TV103, was confirmed to carry a transcriptional region. Assuming that the transcriptional region was a part of a gene (designated as vdtl), we sequenced the region containing its periphery and cDNA of the region. As a result, the transcriptional region contained a putative open reading frame coding for 137 amino acids separated by two introns. TATA box and CAAT box were also found upstream of the transcriptional region. However, vdtl or its presumed amino acid sequences did not show any significant homology to known genes or proteins in available data bases. Southern and Northern hybridization analyses showed that vdtl was found only in the isolates of the tomato pathotype among 19 tested isolates of V. dahliae and was transcribed in culture mycelia, spores, microsclerotia of TV103 as well as the tomato seedlings infected with the fungus.

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Decomposition of organic materials in the process of organic fertigation

Akimasa Nakano, Yoichi Uehara, Hideo Naitoh, Akira Yamauchi

Article type: Article
2001 Volume 55 Issue 1 Pages 21-27
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_21

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Corn steep liquor (CSL), which is an organic product derived from corn starch factories, contains about 3% each of N, P_2O_5 and K_2O. Attempts were made to use CSL as a sole fertilizer for fertigation of tomato cultivation. The number of aerobic bacteria in the soil of the CSL fertigation plot was ten times higher than that of the plot with basal dressing and fertigation using chemical fertilizers (inorganic fertigation). The activity of the soil enzymes relating to organic matter decomposition, ie. protease, β-glucosidase, α-glucosidase and phosphatase in the CSL plot was higher than that in the plot with basal dressing and inorganic fertigation. The increase of the activity of the bacteria and soil enzymes by CSL application led to the rapid decomposition and mineralization of CSL. The processes involved in organic fertigation were effective in supplying sufficient amount of nutrients for tomato growth, because the yield of tomato grown under CSL application was similar to that of the plants with basal dressing and inorganic fertigation.

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Comparison of bacterial and fungal biomass determined by phospholipid fatty acid and direct microscopical analysis in 4 types of upland soils

Tomohito Arao, Seigo Okano, Takashi Nishio

Article type: Article
2001 Volume 55 Issue 1 Pages 29-36
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_29

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We investigated the relationship between the phospholipid fatty acid (PLFA) content and bacterial and fungal biomass in soils incubated in the presence/ absence of cellulose or glucose. PLFA content except for 18 : 2ω6 in soil was correlated with the bacterial biomass estimated by direct bacterial counts (r =0.75 ; p< 0.01, n=66) and the average ratio of bacterial biomass to PLFA content was 4.7±0.2 in 3 types of upland soils. These results suggest that the bacterial biomass can be estimated based on the PLFA content in soil. A positive correlation (r=0.50 ; P<0.01, n=86) was also found between the content of PLFA 18 : 2ω6 and the fungal biomass determined by direct microscopical analysis in 4 types of upland soils. This correlation coefficient increased when the soils containing PLFA 18 : 2ω6 below 0.1 mg g^<-1> dry soil were omitted (r=0.64 ; p<0.01, n=38). In this case, the average ratio of fungal biomass to PLFA 18 : 2ω6 content was 822±71. A similar average ratio was observed in a Low Humic Andosol after application of pig compost (769±149). These results suggest that the PLFA 18 : 2ω6 content could be used to estimate the fungal biomass in soils containing PLFA 18 : 2ω6 above 0.1 mg g^<-1> dry soil. The content of PLFA 18 : 2ω6 increased about three times more than did the fungal biomass just after application of pig compost. In such cases, the PLFA 18 : 2ω6 content could be a relative measure of fungal biomass.

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Some microbial properties of suppressive soil induced by successive inoculations of Rhizoctonia solani anastomosis group 2-2

Mitsuru Sayama, Yoshihisa Homma, Hiromitsu Furuya, Shigehito Takenaka

Article type: Article
2001 Volume 55 Issue 1 Pages 37-44
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_37

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Cultivated soil collected in Hokkaido became suppressive to damping-off caused by Rhizoctonia solani AG2-2-IV and AG4 after 4-5 successive inoculations of R. solani AG2-2-IV or AG4 at 2-wk intervals. It is necessary to apply living mycelium of R. solani into the soil for suppressiveness but cultivation of sugar beet is not always necessary. Growth rate of mycelium of R. solani in the suppressive soil was reduced to about one-half of that in the naturally cultivated soil after 5 days of incubation. No correlation was detected between the suppressiveness of the soil and the population of total fungi, bacteria, actinomycetes and Trichoderma spp. in the soil. However, the suppressiveness was enhanced by incubation of natural soil mixed with living R. solani mycelium and a small amount of suppressive soil. This fact indicated that microorganisms parasitic to R. solani may be involved in the suppressiveness. Suppressiveness was eliminated by aerated steam treatment at 55℃ for 30 minutes, indicating that heat-resistant bacteria are not the major suppressive factors. The suppressive factor was not sensitive to benomyl mixed in soil, although members of Trichoderma, Gliocladium and Verticillium, which are well known to be parasitic to R. solani, were sensitive to benomyl. These results suggest that heat-sensitive and benomyl-tolerant microorganisms are the main factors for the suppressive soil.

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Effects of seed size of Japanese red pine Pinus densiflora on colonization of pine seedlings by ectomycorrhizal Basidiomycete Suillus granulatus and initial growth of seedlings

Takahiro Tateishi, Ayato Kohzu, Hideo Yukutake, Eitaro Wada

Article type: Article
2001 Volume 55 Issue 1 Pages 45-53
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_45

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Effects of seed size of Japanese red pine (Pinus densiflora Sieb. et Zucc.) on the colonization by ectomycorrhizal Basidiomycete Suillus granulatus (L.: Fr.) O. Kuntze and initial growth of the pine seedlings were examined. Pine seedlings at 1 month of age were infected with S. granulatus and were grown for 3 months at 23.5℃ under fluorescent light. The relationships among the parameters related to the seed size, growth of seedlings and mycorrhizal colonization were investigated. There was a significantly positive correlation between the fresh weight of seeds and some growth parameters of the seedlings and between mycorrhizal colonization and the parameters related to root growth. In contrast, a significantly negative correlation was observed between mycorrhizal colonization and the height of the seedlings. There was no significant correlation between the fresh weight of seeds and mycorrhizal colonization. These results indicate that the seed size promoted the growth of seedlings at early stages after germination, and that mycorrhizal colonization may suppress the above-ground development of seedlings. Although the seed size does not affect the mycorrhizal colonization directly, the positive and negative correlations of the seed size with the parameters for the initial growth of the seedlings and mycorrhizal colonization suggest the presence of indirect effects of the seed size on the growth of pine seedlings and development of mycorrhizas at the early stages after germination and infection with mycorrhizal fungi.

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Perspectives in Soilborne Disease Researches of Japanese Ornamental Industry : Invitation to Ornamental Pathology

Seiji Uematsu

Article type: Article
2001 Volume 55 Issue 1 Pages 55-63
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_55

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 65-
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_65

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 66-67
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_66

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 67-
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_67

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 68-
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_68_1

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 68-69
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_68_2

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 69-70
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_69

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 70-71
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_70

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[title in Japanese]

[in Japanese]

Article type: Article
2001 Volume 55 Issue 1 Pages 71-72
Published: April 01, 2001
Released on J-STAGE: May 31, 2017

DOIhttps://doi.org/10.18946/jssm.55.1_71

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