1999 Fiscal Year Final Research Report Summary
Chemical Studies on movement and sensivility in plants
| Project/Area Number |
09101001
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| Research Category |
Grant-in-Aid for Specially Promoted Research
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| Allocation Type | Single-year Grants |
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| Review Section |
Chemistry
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| Research Institution | Keio University |
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Principal Investigator |
YAMAMURA Shosuke Keio Univ., Chemistry., Professor, 理工学部, 教授 (40076708)
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| Co-Investigator(Kenkyū-buntansha) |
HASEGAWA Koji Tsukuba Univ., Applied Biology, Professor, 応用生物系, 教授 (70094167)
UEDA Minoru Keio Univ., Chemistry., Assistant Professor, 理工学部, 講師 (60265931)
KOSEMURA Seiji Keio Univ., Chemistry., Assistant Professor, 理工学部, 講師 (70231313)
TOMITA Kaori yokotani (富田 香織) Tsukuba Univ., Applied Biology, Assistant, 応用生物系, 助手 (10217531)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Phototropism / Growth inhibiter / SAUR gene / Phototropic natural products / Nyctinasty / Leaf-closing substance / Leaf-opening substance / Biological clock |
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| Research Abstract |
Phototropism has been known to be caused by a lateral gradient of growth-promoting auxin in the bending organ (Cholodny-Went theory). In contrast to the C.-W. theory, Brinsma and Hasegawa recently found that the shaded half did not contain more auxin than the illuminated ones. Instead it was found that the even distribution of auxin was accompanied by a lateral gradient of growth inhibitory substances during phototropic curvature. We have isolated some photo-induced growth inhibitory substances related to phototropism. 6-Methoxy-2- benzoxazolinone from light-grown maize (Zea mays L.) shoots was proved to inhibit the interaction between auxin and ABP1, the primary structure of which was determined, resulting in the growth inhibition in the illuminated side. Our present study has led to a new theory of "phototropism".
Many plants close their leaves at night and open during daytime. Such a circadian rhythm has been known to be controlled by their internal clock. We were able to isolate each pair of leaf-closing and -opening substances from five different species. Of the pair, one of them was found to be β-D-glucoside. The leaf movement of these plants is due to the balance of concentration between them, which is controlled by the activation of β-D-glucosidase. Based on our extensive study, a new mechanism of leaf movement has been presented.
In the case of Mimosa pudica, we could isolate a true active stimulant (activity : ca. 10-8〜10-9M) from the same plant, which consists of three components (potassium L-malate, magnesium transaconitate and dimehylammonium salt) in addition to the pair of leaf-closing and opening substances related to circadian rhythm.
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