| Abstract: | Protoplasts of Brassica carinata Braun. (accession No. 84A165) were enzymatically isolated from hypocotyls and cotyledons of 3–5 day-old test-tube seedlings or first true leaves taken from greenhouse grown plants at a three-leaf stage. The protoplasts were suspended in a P-B liquid medium solidified with 0.15%–0.3% low melting agarose which formed a thin layer floating on the surface of the liquid medium. The optimum protoplast density was ranging from 5× l03 to 1 × 104/ml. As for the hypocotyl protoplasts, the first division was observed after 48 h in the culture. The division frequency reached 21% and 34% at day 3 and 6 respectively. The initiation of cell division in the case of cotyledon and mesophyll protoplast culture was late, usually at day 5, and the division frequency was also somewhat lower. One week after culture, the cultures were transferred to fluorescent light condition with an intensity of about 1000 lx. A dilution medium DPDK3 was then added and the dilution procedure was repeated at one week interval thereafter. One month after culture, microcalli with 300–500 μm in size were formed. It was also found that in some cases globular embryoid structure protruded on the callus surface. Totally, a 2%–3% plating efficiency was achieved. Shoot regeneration occurred when cotyledon and mesophyll protoplast-derived calli were transferred onto a modified MS medium supplemented with NAA 0.1, BA 3 mg/l. Individual shoots were rooted on a rooting medium supplemented with 0.2 mg/l of IAA. Intact plants with normal morphology were eventually produced. |
