The influences of ethylene inhibitors (AgNO3 and silver thiosulfate) and cytokinins (BAP and TDZ) on shoot regeneration from cotyledon and hypocotyl explants of B. napus cv. Youngsan were investigated. The presence of 50 μM Silver thiosulfate (STS) in shoot regeneration medium formed shoots at 60-68% after 3-4 weeks of culture, which was enhanced by 2-fold compared to that of Silver nitrate (AgNO3). Moreover, cotyledon explants were more regenerative than hypocotyls; shoots from cotyledon explants began to occur 4-5 days earlier than that of hypocotyl explants. TDZ at a concentration of 8-10 μM was effective for shoot regeneration, compared with BAP. Consequently, the optimal shoot regeneration response was observed in medium supplemented with 50 μM STS + 8 μM TDZ. In transmission electron microscopy (TEM) analysis, higher density of silver nanoparticles was shown to be accumulated widely inside the cell wall and plasmodesmata of regenerating leaf cultured in medium supplemented with AgNO3. By contrast, in the cell cultured in medium with STS, fine-grained deposits were partly observed in the surroundings of the cell wall.

• Kyung Hee Roh(Department of Agricultural Biotechnology, National Academy of Agricultural Science, RDA) Corresponding Author
• Han-chul Kang(Department of Agricultural Biotechnology, National Academy of Agricultural Science, RDA)
• Jong-Bum Kim(Department of Agricultural Biotechnology, National Academy of Agricultural Science, RDA)
• Hyun Uk Kim(Department of Agricultural Biotechnology, National Academy of Agricultural Science, RDA)
• Kyeong-Ryeol Lee(Department of Agricultural Biotechnology, National Academy of Agricultural Science, RDA)