1991 Fiscal Year Final Research Report Summary
The Growth and Nitrogen Uptake by Tomato Plants in the Night-time
| Project/Area Number |
02660033
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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 |
園芸・造園学
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| Research Institution | Okayama University |
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Principal Investigator |
MASUDA Masaharu Okayama Univ. Fac. of Agriculture. Professor, 農学部, 教授 (90026617)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Tomato / Night-growth / Labeled nitrogen / Mineral transport / Xylem sap analysis / Mineral nutrition |
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| Research Abstract |
1. For tomato plants, the growth rate was four-fold greater in weigh in weight in the night-time than in the daytime. However, there was no difference in root elongation rate between night-time and daytime.
2. The mineral transport concentration from root to shoot was investigated by xylem sap analysis. Exudation rate reached maximum near at noon. The nitrate concentration showed a little change, but phosphate concentration increased rapidly from evening, and reached maximum around at 10 : 00 P. M. . In contrast to phosphate, potassium concentration reached maximum around at 10 : 00 A. M. .
Mineral concentrations decreased greatly in shaded plants by 30% of sunlight intensity except phosphate ; the higher phosphate concentration at any time in the shaded plant than in the control one.
The concentrations of nitrate, phosphate, calcium and magnesium decreased as plants aged, whereas potassium concentration did not change irrespective of ages.
3. Night-uptake nitrogen( ^<15>N)was distributed to leaf, stem and root in the ratio of 5 : 1 : 4 in the morning, whereas in the ratio of 7 : 1 : 2 for day-uptake nitrogen. A portion of the night-uptake nitrogen was also transported to the calyx and the peduncle, but not yet to the fruits until the morning.
4. The growth of tomato plants was the greatest under cycles of 4 hours of darkness-20 hours of artificial light(18, 000lux)at 25 C. Tomato plants grown entirely in artificial light exhibited a bend of shoot tip, leaf chlorosis and necrosis caused by the deficiency of calsium and magnesium. Chlorophyll content and green color of leaves were recovered by 1-hour dark interruption.
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