2005 Fiscal Year Final Research Report Summary
PROPAGATION, GROWTH AND FLOWERING PHYSIOLOGY OF ENDANGERED SPECEIS ARISAEMA SIKOKIANUM.
| Project/Area Number |
15580024
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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 |
Horticulture/Landscape architecture
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| Research Institution | KAGAWA UNIVERSITY |
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Principal Investigator |
HASEGAWA Atsushi KAGAWA UNIVERSITY, FACULTY OF AGRICULTURE, PROFESSOR, 農学部, 教授 (70036044)
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| Co-Investigator(Kenkyū-buntansha) |
FUKAI Seiichi KAGAWA UNIVERSITY, FACULTY OF AGRICULTURE, PROFESSOR, 農学部, 教授 (80228858)
KOBAYASHI Tsuyoshi KAGAWA UNIVERSITY, FACULTY OF AGRICULTURE, ASSOCIATE PROFESSOR, 農学部, 助教授 (70346633)
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| Project Period (FY) |
2003 – 2005
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| Keywords | ARISAEMA SHIKOKIANUM / ENDENGERED SPECIES / PHOTOSNTHESIS / BREAS DROMANCY |
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| Research Abstract |
A.sikokianum has a sympodial shoot with a two-year growth cycle. Inflorescence initiation occurred on the apex of the axillary shoot of the lower leaf in May. The apex initiated the spathe and spadix in succession. Floral primodia appeared on the spadix from September to October. In order to verify self-compatibility in A.sikokianum, pollen that was collected from several male plants and cryopreserved for a year was used to pollinate to the same plants when the sexual expression of the plants converted to female. Both self- and cross-pollinated spadices produced seeds, indicating that A.sikokianum is self-compatible. Dormancy of corms broke when corms were exposed to natural low temperature until middle December. Effective temperatures for breaking dormancy was 5℃. Vegetative corms exposed to low temperatures at 5℃ longer showed shorter days to sprout when grown at 20℃. Reproductive corms treated at 5℃ longer showed shorter days to flower. Potted A.sikokianum plants were grown under 28
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, 14 and 4% of light intensity to full sunlight (100%) at an experimental field. Net CO_2 assimilation rate near saturating irradiance (A_<sat>) and chlorophyll fluorescence characteristics at predawn and daytime were measured for well-developed leaves. At the beginning of flowering, A_<sat> and electron transport rate (ETR) in midday were greater in female plants than those of male plants. Both in the male and the female plants at this period, A_<sat> and ETR increased, and light use efficiency (ΔF/Fm') in the midday decreased with the intensity of growing light. No midday depression of ETR in the male plants would be partly ascribed to greater non-photochemical quenching (NPQ), a successful dissipation of excess light energy. The decrease of ΔF/Fm' in the midday recovered until evening, suggesting that chronic photoinhibition can be avoided even in the male plants with smaller photosynthetic capacity. After the flowering, A_<sat> and ETR were decreased and ΔF/Fm' did not recover in the evening. However, at the low light levels (4 and 14%), similar photosynthetic characteristics were shown between the male and the female plants and/or light intensities. These results suggest that A.sikokianum plants growing in the low light have mechanisms to maintain photosynthetic productivity irrespective of sex expressions and light intensities. The productivity of female plants would be supported by greater photosynthetic capacity at the leaf level from the beginning of shoot expansion and flowering. Less
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Research Products
(4 results)
