南方泡桐同源四倍体的诱导及其体外植株再生

Induction of autotetraploid of Paulownia australis and its in vitro plantlet regeneration

【目的】用秋水仙素诱导出南方泡桐同源四倍体,建立其体外植株高效再生系统,为泡桐新品种的培育奠定基础。【方法】以二倍体南方泡桐幼苗叶片为外植体,预培养泡桐不同时间(0,8,16 d)后,置于含不同质量浓度(5,10,20 mg/L)秋水仙素的固液双层培养基上处理泡桐不同时间(24,48,72 h),以诱导其同源四倍体植株,并通过根尖细胞染色体计数和叶片单细胞DNA相对含量的测定,进行变异植株的倍性分析;同时,以其四倍体叶片、茎段和叶柄为外植体,利用不同植物激素不同质量浓度的组合培养基,筛选建立体外植株再生系统的最适培养基。【结果】秋水仙素质量浓度和处理时间对南方泡桐同源四倍体诱导率影响显著,外植体预培养时间影响不显著;在含10 mg/L秋水仙素的MS培养基上处理72 h,未经预培养叶片的四倍体诱导率高达18.8%;同源四倍体幼苗叶片较二倍体大而且厚,叶片单气孔器变大,孔密度变小,叶绿素含量和SOD活性升高,MDA含量和POD活性降低。MS+0.1mg/L NAA+8 mg/L BA、MS+0.3 mg/L NAA+12 mg/L BA和1/2 MS分别是其愈伤组织诱导、芽诱导和根诱导的适宜培养基。【结论】诱导获得了南方泡桐同源四倍体,建立了同源四倍体南方泡桐的体外植株再生系统;叶片是同源四倍体南方泡桐体外植株再生的最佳外植体。

[Objective] Induction of Paulownia australis autotetroploid with colchicines was investigated and the system of in vitro plantlet regeneration with different explants was established in order to lay foundation for the breeding of new variant of Paulownia plants. [Method] The diploidy leaves on the liquid-solid double layer MS media with different colchicines concentrations were used to induce the autotetraploid and the ploidy levels were analysed through chromosome numbering of the plant root tip cells and DNA relative content of the leaf single cell. [Result] The concentrations of colchicine and the treatment periods were significantly different,and pre-culture time was not significantly different to the autotetraploidy induction. The highest induction rate might reach 18. 8% from non pre-cultured leaves treated with 10 mg/L colchicine for 72 h on the MS medium. Leaves of the autotetraploids were larger and thicker,and the stomatal size and density on the leaf larger and thinner than those of the diploid, and the chlorophyll content and SOD activities of the autotetraploids became higher and MDA content and POD activity lower than those of the diploids. MS＋0.1 mg/L NAA＋8 mg/L BA,MS＋0.3 mg/L NAA＋12 mg/L BA and 1/2 MS were the optimal media for shoot and root induction respectively. [Conclusion] The autotetroploid of Paulownia australis was induced and the system of its in vitro plantlet regeneration was established. Moreover, leaves were the suitable explants for the in vitro plantlet regeneration.