1987 Fiscal Year Final Research Report Summary
Studies on the survival mechanismn of plant cells and tissues at super-low temperatures.
| Project/Area Number |
60490004
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
広領域
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| Research Institution | Saitama University |
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Principal Investigator |
SUGAWARA Yasutake Saitama University, Associate Professor, 理学部, 助教授 (70114212)
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| Project Period (FY) |
1985 – 1987
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| Keywords | Protoplasts / Plant Cultured Calls / Freezing resistance / Freezing Injury / Cryopreservation / Marchantia polymorpha / Call wall Regeneration / 冷凍顕微鏡 |
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| Research Abstract |
To elucidate the cellular mechanisms of freezing injury and freezing resistance of plant cells and tissues at super-low temperatures, following studies were performed using protoplasts and cultured cells as experimental materials.
1 Changes in the rate of cell survival after freezing and thawing were examined in protoplasts and cultured cells isolated from several plant species under different freeze-thawing conditions in the presence of cryoprotectants. As a result, most suitable conditions of freeze-thawing for highest survival rate in cryopreservation were shown in protoplasts and cultured cells of each plant species. Further studies were performed to reveal some changes in physiological activities of freeze-thawed cells.
2 A simple and rapid method for determining the rate of cell survival by luciferin- luciferase assay was developed to determine the rate of cell survival in a small size of sample of in a shoot apex.
3 It was revealed that the freezing resistance of regenerated protoplasts of Marchantia polymorpha increase in parallel with the rate of call wall regeneration during an initial period of protoplast culture. The highest freezing resistance was observed after 18 to 22 hours of protoplast culture. A rapid loss of freezing resistance of regenerated cells was observed when they were treated with cell wall digesting enzyme. These results suggest that regenerated cell wall and/or plasma membrane forming new call wall play an important role in gaining the freezing resistance in Marchantia protoplasts. Further studies were performed with a cryomicroscope and freeze-fracture method and the mechanisms of freezing injury and freezing resistance were discussed.
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