| Project/Area Number |
14560229
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Zootechnical science/Grassland science
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| Research Institution | Minamikyushu University |
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Principal Investigator |
HIROSE Daisuke Minamikyushu University, Faculty of environmental landscape architecture, Assistant professor, 環境造園学部, 助教授 (80269125)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
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| Keywords | alfalfa / ammonium nitrogen / nitrate nitrogen / nitrogen fertilizer / root activity / root length / root number / root system / 施肥窒素 / 窒素濃度 / pH / α-ナフチルアミン / 硝酸還元酵素 / 養水分吸収能 / 根端数 / 分枝根 |
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| Research Abstract |
The objective of the present research was to compare the effects of ammonium and nitrate nitrogen on the development and functions of the alfalfa root system. The results are presented below.
1. In a culture medium with a nitrogen concentration of 20 ppm, root systems in fertilized with ammonium nitrogen were longer than those in fertilized with nitrate nitrogen. This was attributable to differences in both the number of lateral roots and the lengths of individual lateral roots.
2. When the nitrogen concentration of the culture medium was varied, the degree of development of taproots in fertilized with ammonium nitrogen was similar to that in fertilized with nitrate nitrogen to a nitrogen concentration of 20 ppm. However, at concentrations of 30 and 40 ppm, taproots were narrower and the degree of development of root branches was superior in fertilized with nitrate nitrogen. For lateral roots, application of ammonium nitrogen produced thinner lateral roots and a superior degree of develo
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pment of root branches at concentrations up to 20 ppm, as did nitrate nitrogen at concentrations of 30 ppm or higher.
3. Growth and root system development of alfalfa fertilized with nitrate nitrogen at a nitrogen concentration of 20 ppm in culture medium was inferior to that fertilized with ammonium nitrogen. Rather than being due to the use of nitrogen at levels exceeding the activity of nitrate reductase in alfalfa, the cause may be in adequate absorption of the nitrate ion in the very early stages.
4. The difference in taproot length after application of ammonium nitrogen fertilizer and nitrate nitrogen fertilizer at a concentration of 20 ppm in cultured medium may have been due to a difference in root physiological activity up to the 40th day after sowing. However, the variations in root system development for the two nitrogen sources at different nitrogen concentrations may have been attributable to differences in root physiological activity.
5. These results suggest that decreased pH of the culture medium is not responsible for the superior root system development of alfalfa fertilized with nitrate nitrogen at nitrogen concentrations of 30 ppm or higher, as compared with use of ammonium nitrogen. Less
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