栽培薯蓣茎段离体再生体系的建立

Establishment of an In Vitro Regeneration System for Stem Segments of Cultivated Dioscorea polystachya

为建立栽培薯蓣(Dioscorea polystachya)组培再生体系,以茎尖及茎尖下4个不同长度的茎段为外植体,探讨了不同浓度植物生长调节剂、培养基类型及茎段对腋芽诱导和植株再生的影响。结果表明,培养基配比为MS+1.0 mg·L^(–1)6-BA+0.5 mg·L^(–1)KT和茎尖下12–20 cm的茎段为栽培薯蓣不定芽诱导的最佳组合,诱导率达90.0%;继代培养最适培养基配方为MS+0.5 mg·L^(–1)6-BA+0.05 mg·L^(–1)NAA+0.1 mg·L^(–1)KT,低浓度NAA固定时,增殖系数在一定范围内随着6-BA浓度的升高而增高;在相同外源激素条件下,快繁生根采用DKW培养基明显优于常规1/2MS培养基,生根率显著提高,达92.86%。添加1 mg PVP以及增加转接次数均能明显降低褐化率。该研究有效解决了栽培薯蓣种质资源离体稳定繁殖取材部位优化的问题,为规模化生产栽培薯蓣优质脱毒苗奠定了良好基础。

To establish a tissue culture regeneration system for cultivated Chinese yam(Dioscorea polystachya),the effects of different concentrations of plant growth regulators,and stem segments on axillary bud induction and plant regeneration were investigated with different concentrations of plant growth regulators,media types,and shoot tips and stem segments at four different positions under the shoot tip as explants.The results revealed that MS+1.0 mg·L^(–1)6-BA+0.5 mg·L^(–1)KT hormone ratio and 12–20 cm stem segment under the stem tip were the best formulas for the induction of adventitious buds in D.polystachya,and the induction rate reached 90.0%.In the subculture,the optimal concentration was MS+0.5 mg·L^(–1)6-BA+0.05 mg·L^(–1)NAA+0.1 mg·L^(–1)KT,and the proliferation coefficient increased with increasing of 6-BA within a certain range when the low concentration of NAA was constant.With the same concentration of exogenous hormones,DKW medium was significantly better than the conventional 1/2MS medium,and the rooting rate is significantly improved,reaching 92.86%.Adding 1 mg PVP(polyvinylpyrrolidone)and increasing the number of transfers can significantly reduce browning.This study effectively solved the problem of optimizing the explant position for the stable of in vitro propagation of cultivated yam germplasm resources,laying a good foundation for the large-scale production of their high-quality virus-free seedlings.