| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Research Abstract |
Callus induction and rapid callus propagation in Laminariales plants, which are industrially and ecologically important seaweeds, cannot yet be applied for practical use to select and propagation of desired strain. There is a lack of knowledge regarding the physiological mechanism of callus induction and its growth. In this study, we examined the optimal conditions of callus induction and growth of Laminaria japonica sporophyte and discussed the physiological status of callus. The obtained results are summarized as described below.
1.The optimal water temperature and salinity were 10℃ and more than 27.5 psu, respectively, which was similar to that of a whole plant.
2.Nutrient-poor conditions decreased the induction rate of callus, and then the growth was stopped. In addition, vitamins were not effective to promote the callus induction.
3.Three chelating substances including EDTA, EGTA, and NTA, slightly promoted callus induction or did not affect the induction. However, enrichment of nutrients with chelating substances resulted into the decrease the induction rate of callus.
4.The callus induction occurred even in the dark, but the growth gradually decreased. The callus induction rate was significantly higher under red light compared with those under white and blue lights. Inversely, sorus formation was promoted by the irradiation of blue light, and was inhibited under red light.
5.The addition of auxin and cytokinins to the culture medium promoted callus formation. It is suggested from microscopic observations that auxin plays an important role for cell division and the elongation, and cytokinins is effective to inhibit the discoloration. In addition, the difference of callus induction rate among parts along the sporophyte seemed to be due to the content of these plant growth regulators.
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