2002 Fiscal Year Final Research Report Summary
THE ROLE OF PLANT HORMONE AND CARBOHYDRATE IN THE GRAIN FILLING OF RICE PLANT
| Project/Area Number |
12660010
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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 |
作物学
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NAKAMURA Teiji TOHOKU UNIVERSITY, GRADUATE SCHOOL OF AGRICULTURAL SCIENCE, ASSISTANT PROFESSOR, 大学院・農学研究科, 助手 (70155844)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAJIMA Takayuki TOHOKU UNIVERSITY, FACULTY OF AGRICULTURE, RESEARCH ASSISTANT, 大学院・農学研究科, 教務職員 (80241553)
GOTO Yusuke TOHOKU UNIVERSITY, GRADUATE SCHOOL OF AGRICULTURAL SCIENCE, ASSOCIATE PROFESSOR, 大学院・農学研究科, 助教授 (80122919)
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| Project Period (FY) |
2000 – 2002
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| Keywords | rice / spikelet position / light / grain growth / grain filling / endosperm / phytohormone / carbohydrate |
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| Research Abstract |
The purpose of this study is to elucidate the role of phytohormone and carbohydrate in the grain filling of rice.
1. Early growth and dry matter accumulation of grains
Shading after the heading decreased the early growth rate and increased the linear dry matter accumulation rate in the grain at the lower spikelet positions. Both the shading before the heading which reduced the carbohydrate content at the heading and elevated CO_2 after the heading had no effects on the early grain growth, but increased the linear dry matter accumulation rate in the grain. These results suggest that lights promote the early grain growth not through the increment of carbohydrate supply, but through phytohormone which concerned with the grain growth and the endosperm development.
2. Diurnal changes of the early grain growth
Grains were expanded and cells of maternal tissue were divided during the day at the early developmental stage. The level of abscisic acid was higher in the day than in the night, but the level of cytokinin was higher in the night than in the day. Sugar pool sizes of grains did not show the clear diurnal change. These results suggest that light regulates the early grain growth through the abscisic acid and, abscisic acid acts as a growth promoter.
3. Varietal differences in early grain growth and characteristics of grain filling
Under the defoliated condition, there was a varietal difference in the degree of the growth delay of the grains at the lower spikelet positions within panicle. The variety in which the early gram growth is difficult to delay had higher endosperm cell number and final grain weight than the variety in which the growth is easy to delay. It seemed to have to elucidate the varietal difference in the early grain growth, physiologically.
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