• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.69-77
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• 2003

Brassinosteroids are known to promote cell elongation in a wide range of plant species but their effect on cell division has not been extensively studied. The effect of brassinolide on the kinetics and final division frequencies of regenerating petal protoplasts of Petunia hybrida Vilm v. Comanche was examined. Under optimal auxin and cytokinin conditions, 10-100 nM brassinolide not only reduced the time of first cell division by 4.5 days but also altered the final division frequencies after 10 days of culture. One micromolar brassinolide showed the same acceleration of first cell division but inhibited the final division frequency by approximately 9%. Under sub-optimal auxin conditions, 10-100 nM brassinolide accelerated the first cell division, but no significant increase in the 8-10 days final division frequencies. Isolated protoplasts may provide a useful model system for the investigation of the molecular mechanisms of brassinosteroid action on cell division and proliferation in higher plants.

• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.63-67
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• 2003

Brassinosteroids are known to promote cell elongation in a wide range of plant species but their effect on cell division has not been extensively studied. The effect of brassinolide on the kinetics and final division frequencies of regenerating petal protoplasts of Petunia hybrida Vilm v. Comanche was examined. Under optimal auxin and cytokinin conditions, 10-100 nM brassinolide not only reduced the time of first cell division by 4.5 days but also altered the final division frequencies after 10 days of culture. One micromolar brassinolide showed the same acceleration of first cell division but inhibited the final division frequency by approximately 9%. Under sub-optimal auxin conditions, 10-100 nM brassinolide accelerated the first cell division, but no significant increase in the 8-10 days final division frequencies. Isolated protoplasts may provide a useful model system for the investigation of the molecular mechanisms of brassinosteroid action on cell division and proliferation in higher plants.

• Journal of Plant Biotechnology
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• v.35 no.2
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• pp.121-126
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• 2008

Protoplasts from cabbage and radish were isolated and fused symmetrically by PEG treatment. The PEG treated mixture of high concentrated protoplasts produced lots of micro-calli after $2{\sim}3$ weeks. The microcalli developed to normal calli and shoots were regenerated from the calli. A total of 218 shoots were regenerated, but none of them contained the NWB-CMS specific DNA marker, indicating that the transfer of the radish NWB-CMS character into cabbage did not occur. However, ISSR analysis revealed that the cell fusion between protoplasts from radish and cabbage was occurred (3 out of 208 plantlet). The fused regenerants possessed the characteristics of source plants used for protoplast fusion. After vernalization, three regenerants were flowered with white petal color as seen in radish. Only three seeds were able to obtain from one regenerant by backcrossing with the cabbage pollen.