1993 Fiscal Year Final Research Report Summary
Genetic Study of Nitrate Transport across the Plasma Membrane of Root Epidermal Cells in Some Crop Plants
| Project/Area Number |
03660007
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Breeding science
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| Research Institution | University of Osaka Profecture |
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Principal Investigator |
HASEGAWA Hiroshi University of Osaka Prefecture, Assistant Professor, 附属研究所, 講師 (00090457)
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| Co-Investigator(Kenkyū-buntansha) |
INOUE Masayoshi Kyoto Prefectural University, Professor, 農学部, 教授 (90090456)
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| Project Period (FY) |
1991 – 1993
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| Keywords | Nitrate uptake / Barley / Rice / Wheat / Km and Vmax / Mutant / Low-input cultivation / Seedling |
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| Research Abstract |
Breeding of crops with efficient use of plant nutrient is one of the goals for low-input crop production. In this study, two kinetic parameters, Km and Vmax, for high affinity nitrate uptake by young seedlings were determined in several crop plants for evaluating the expression of nitrate uptake gene (s). Summary of the results are shown as follows.
1) In twenty Japanese barley cultivars, Km and Vmax were 50.9-111.7 mu M and 2.24-4.99 mu mol/g/h, respectively. IIowever, these results were thought to be underestimated because of experimental procedure. 2) In barley genotypes with different water tolerance at seedling stage, Km and Vmax were 143.0-209.4 mu M and 3.37-7.85 mu mol/g/h, respectively. No relationships between the kinetic parameters and water tolerance was observed. 3) In sixteen rice cultivars including both indica and japonica, Km and Vmax were 75.7-130.3 mu M and 4.30-7.17 mu mol/g/h, respectively. In the cultivars of indica and japonica showing similar level of Km, indica cultivars tended to show lower Vmax than japonica cultivars. 4) Km and Vmax in several genotypes of wheat, rye and Triticale were similar level of those of barley and rice. 5) In four rice mutants affecting nitrate assimilation, M605, a chlorate hypersensitive mutant, showed significantly higher Km than that of the wild type, Norin 8. Furthermore, there was difference in ratio of nitrate uptake ability from 40 mu M KNO_3 to that from 400 mu M KNO_3 in 145 rice genotypes, suggesting variability in the kinetic parameters.
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