1995 Fiscal Year Final Research Report Summary
Study of regulatory mechanisms of haustorial induction in Cuscuta japonica, a parasitic flowering plants, and survey for useful substanes containing in the haustoria.
| Project/Area Number |
06804049
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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 |
植物生理
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| Research Institution | Niigata University |
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Principal Investigator |
FURUHASHI Katsuhisa Niigata University, Faculty of Science, Department of Biology, Professor, 理学部, 教授 (90022714)
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| Co-Investigator(Kenkyū-buntansha) |
SUGAI Michizou Toyama University, Faculty of Science, Department of Biology, Professor., 理学部, 教授 (60109098)
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| Project Period (FY) |
1994 – 1995
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| Keywords | Cuscuta japonica / phytochrome / parasitic plant / haustoria / action spectrum / far-red light |
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| Research Abstract |
When seedlings of Cuscuta japonica, grown with Vigna radiata (the host plant) in a flower pot for 6 days under white light, were irradiated with far-red or blue lights (ca. 6 mumol photons m^<-2> s^<-1>), the seedligs parasitized to V.radiata. However, no parasitism of the seedlings was observed under red, white lights and in the dark. The parasitic behavior of seedlings of C.japonica was observed even if an acrylic stick was used as a substitute for the host plant. Haustoria development occurred when apical and subapical regions of the seedlings were held between two plate glasses kept ca. 0.7mm apart and irradiated with far-red light. However, no haustorium was induced by either the holding or the irradiation alone. These results indicate that parasitism of Cuscuta japonica is controlled by the cooperative effect of two physical signals, far-red light and an appropriate pressure by touch.
To elucidate the photoreceptor for this photo-induction of the haustoria, fluence-response relationships were measured at wavelength from 340nm to 800nm. The action spectrum for the induction of haustoria had a pronounced peak at 740nm and a small peak at 420nm. The spectrum for reversal of the induction exhibited a pronounced peak at 680nm and a small peak at 380nm. Differential spectrum calculated from these action spectra was resemble to that of absorption spectrum in tobacco phytochrome. These results indicate that photo-induction of haustoria in Cuscuta japonica is mediated by phytochrome. This is the first reliable evidence of phytochrome participation for haustorial development in parasitic plants.
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Research Products
(2 results)
