| Abstract: | Abstract Flax is an important natural material for the linen spinning industry and as an oil crop in China. Flax products worth US $100 million are exported every year. Recently, with the development of a market economy and China's entry into the WTO, farmers and flax factories have shown a need for new varieties that have a short vegetation period, are resistant to herbicides and lodging, and have a high fiber content. In order to resolve these problems quickly, we have studied flax genetic transformation since 1998. The paper is about flax genetic transformation by Agrobacterium tumefaciens strain EHA105. The explants were hypocotyl segments from 5-7 day old seedlings. The segments cannot form a callus when the concentration of kanamycin is 30 mg/L and 50 mg/L. Therefore, 50 mg/L of kanamycin was selected as an efficient concentration to select the transgenic plants. The segments of hypocotyl were treated with EHA105 and then were inoculated in different media (Ms, B5, N6). The experiment showed that Ms is a preference medium for flax genetic transformation. Agrobacteriumtieated segments of hypocotyl were cultured on the surface of modified Ms medium (Ms agar medium supplemented with 3.5 mg/L IAA, 2 mg/L KT, 150 mg/L LH). Callus was formed by 71.4%-81.6% of the hypocotyls. Callus inoculated in a regenerative medium of Ms with little BA and NAA could regenerate at the rate of 31.8%-40.2%, and 87.4% of regenerative plants could root in the medium of 1/2 Ms supplemented with 0.001 mg/L NAA. This transformation system has been tested by the GUS-INT gene. After co-cultivation of the segments of hypocotyl and GUS-INT, the segments of hypocotyl were moved to callus medium. After 3 days, the transformation rate of new callus was 72.0%; after 4 weeks the transformation rate of callus was 24.0%; the transformation rate of regenerative plants was 7.5%. The experiment allowed for the establishing of a flax genetic transformation system mediated by Agrobacterium tumefaciens. |
