同源四倍体青花菜离体再生及其倍性鉴定

以同源四倍体青花菜带柄子叶为外植体，研究其离体再生体系。结果表明： 10 d苗龄外植体在MS + 0.05 mg·L^-1 NAA + 3.0 mg·L^-1 6-BA+0.8% 琼脂 + 3% 蔗糖培养基上不定芽的再生频率最高为63.3％；继代培养(MS + 0.04 mg·L^-1 NAA + 4.0 mg·L^-1 6-BA + 0.8% 琼脂 + 3% 蔗糖)增殖系数为6，诱导(1/2MS + 0.1 mg·L^-1 NAA + 0.7% 琼脂 + 3% 蔗糖)生根率100％，移栽成活率90％。流式细胞技术分析及染色体计数鉴定结果表明，再生植株的DNA相对含量为二倍体的2 倍，染色体数为2n=4x=36。

Regeneration of Autotetraploid Broccoli in Vitro Culture and Identification of the Ploidy

The frequency of shoot regeneration in autotetraploid broccoli was studied. Cotyledons with petiole as explants were cultured on MS media with different combinations of growth regulator. The effects of growth regulator combinations on induction of shoots were evaluated. The optimal media for inducting shoots were MS media containing 0.8% agar and 3% sucrose supplemented with 3.0 mg·L^-1 6-BA, 0.05 mg·L^-1 NAA. The shoot induction percentage was 63.3%. Then each shoot was transplanted on the MS medium containing 0.04 mg·L^-1 NAA and 4.0 mg·L^-1 6-BA proliferating about 6 times. The use of 0.1 mg·L^-1 NAA in the rooting medium increased the number of healthy roots per rooted plant (root ratio was 100%). In this study, we established high-efficient shoot regeneration system of autotetraploid broccoli and analyzed the ploidy stability of regenerates using flow cytometry. The result showed that the tetraploid relative DNA content was about two times of control. The identified result of flow cytometry according to the chromosome analysis implied the regeneration plantlets keep the original ploidy.