白及假鳞茎薄片诱导不定芽及快繁体系的构建

以白及(Bletilla striata)假鳞茎为外植体,根据上、中、下部位切取薄片,探索假鳞茎不同部位BA、NAA和TDZ对假鳞茎薄片诱导不定芽的影响,比较假鳞茎薄片不同厚度对褐化率和出芽数的影响,采用正交试验,研究了BA和NAA对不定芽增殖的效果,并对组培苗进行壮苗、生根和移栽。结果表明:假鳞茎的部位对诱导不定芽作用极显著,下部的出芽率显著高于上部和中部,BA和TDZ对诱导不定芽作用显著,NAA对诱导不定芽作用不显著。最佳诱导不定芽的方式为假鳞茎下部薄片在基本培养基+2.0 mg·L^-1BA+1.0 mg·L^-1TDZ的培养基上培养4周,出芽率为93.3%,出芽数为15个,厚度为1.6~2.0 mm的假鳞茎薄片其褐化率最低。最佳的增殖培养基为基本培养基+1.5 mg·L^-1BA+0.3 mg·L^-1NAA,增殖系数达4.3,平均苗高为7.8 cm。本研究成功建立了白及假鳞茎薄片诱导芽为关键技术的快繁技术体系,为白及种质资源创新奠定了基础。

Shoot Regeneration from Transverse Thin Cell Layers of Pseudobulbs and Micropropagation of Bletilla striata

Pseudobulbs of Bletilla striata were taken as initial explants and cut averagely for three transverse thin cell layers-upper position, middle position and lower position to culture on different media. Different parts of pseudobulbs, plant growth regulators and their concentrations were used to study the effects on shoots regeneration from pseudobulb transverse thin cell layers. The thickness of pseudobulb transverse thin cell layers were also used for explants for comparing the browning rate and the number of shoots. Orthogonal design was used to study the effects of BA and NAA for shoots micropropagation. The micropropagated shoots were cultured on a medium for being strong and rooting prior to transplanting to soil. The results showed that:Position of pseudobulb transverse thin cell layers significantly affected shoot induction. Lower part of pseudobulbs were significant easier to induce shoots than upper part and middle part. TDZ and BA also had obvious effect on shoot induction. NAA had no obvious effect on shoot induction. Lower parts of pseudobulb transverse thin cell layers cultured on basic medium+2.0 mg·L^-1 BA+1.0 mg·L^-1 TDZ for 4 weeks was the optimal treatment to induce shoots. The induction rate was 93.3% and the number of shoots was 15. Pseudobulb transverse thin cell layers(1.6-2.0 mm in thickness) were scarcely browning. Basic medium+1.5 mg·L^-1 BA+0.3 mg·L^-1 NAA was the optimal medium for micropropagation. The multiplication factor was 4.3, and the length of shoots was 7.8 cm. Shoots regenerated directly from pseudobulb transverse thin cell layers and micropropagation system of B.striata was established successfully, which laid a foundation for innovation of germplasm resources.