蒙古沙冬青子叶节诱导培养再生植株的研究

Research on Cotyledonary Nodes Regeneration System of Ammopiptanthus mongolicus

[目的]建立蒙古沙冬青子叶节丛生芽再生体系。[方法]以蒙古沙冬青子叶节为外植体,研究种子萌发培养基中6-BA浓度、子叶节萌发天数、丛生芽诱导的基本培养基及6-BA浓度对丛生芽诱导的影响和外源激素对丛生芽伸长及生根的影响。[结果]表明:(1)添加6-BA的萌发培养基与不添加的相比能够显著促进子叶节的生长及子叶节丛生芽的诱导,且6-BA浓度在2.0 mg·L-1时,诱导率最高可达73.3%,平均芽数2.26个;(2)种子萌发天数对子叶节丛生芽的诱导有显著影响,萌发7 d的子叶节丛生芽诱导率最高,诱导率为74.7%,但与萌发9、11 d的子叶节丛生芽诱导率差异不显著;(3)MS和B5培养基对丛生芽诱导的影响差异不显著,但B5抑制褐化的效果显著好于MS;(4)采用1.0 mg·L-16-BA+0.3 mg·L-1IAA激素组合有利于丛生芽伸长,伸长率为60.5%;(5)不同浓度生长素组合均能促进丛生芽幼苗生根,1.0 mg·L-1IBA生根率最大,生根数最多。[结论]最佳蒙古沙冬青子叶节丛生芽再生体系为:以在MS+2.0 mg·L-16-BA培养基中黑暗培养7 11 d的幼苗子叶节为外植体,在B5+1.0mg·L-16-BA培养基中诱导丛生芽,待丛生芽长约0.3 0.5 cm后,转入B5+1.0 mg·L-16-BA+0.3 mg·L-1IAA培养基中进行伸长培养,当丛生芽伸长至2 3 cm时,单株切下转入1/2 B5+1.0 mg·L-1IBA培养基中生根,该体系与愈伤组织培养相比能缩短培养时间,改善褐化严重、玻璃化等问题,可为蒙古沙冬青的扩繁及进一步开展遗传转化奠定基础。

[Objective]To establish cotyledonary nodes regeneration system of Ammopiptanthus mongolicus. [Method]The effects of concentrations of 6-BA in seed germination medium,seed germination days,type of basal induction medium and 6-BA concentrations on the induction of cluster bud were studied using cotyledonary nodes of A.mongolicus as explants. The effects of exogenous hormones on elongation and rooting of explants were discussed as well. [Result] The results showed that：（1） The medium containing 6-BA can significantly promote the cotyledonary node growth and the induction of cluster bud compared to the medium without 6-BA. And when the 6-BA concentration was at 2. 0 mg·L-1,the induction rate was up to 73. 3% with 2. 26 buds in average.（2） The days of seed germination also had a significant effect on the induction rate of cluster bud. The induction rate of the 7-dayold cotyledonary node reached the maximum of 74. 7%,but had no statistically significant difference with the induc-tion rate of the 9-,and 11-day-old cotyledonary nodes.（3） B5 or MS as the basal medium for induction of cluster bud had no difference,but B5 worked better in inhibiting browning.（4） For elongation culture,the optimal condition was 1. 0 mg·L-16-BA ＋ 0. 3 mg·L-1 IAA with an elongation of 60. 5%.（5） Although the root can be induced from the combination of different concentrations of auxins,the best rooting rate and the maximum number of root occurred when IBA was 1. 0 mg·L-1. [Conclusion] The optimal cotyledonary nodes regeneration system of A. mongolicus includes the following steps： the cotyledonary nodes,cultivated on the MS medium containing 2. 0 mg·L-16-BA in the dark after 7 to 11 days,are used in B5 medium containing 1. 0 mg·L-16-BA to regenerate cluster bud. When the length of buds is about 0. 3-0. 5 cm,they are transferred to B5 medium with 1. 0 mg·L-16-BA and 0. 3 mg·L-1 IAA for elongation culture. When the clumps stretch to 2-3 cm,the single plants are cut into 1/2 B5 ＋ 1. 0 mg · L-1 IBA medium to take root. Compared with the callus tissue culture,this process can shorten the culture time,improve the serious brown and vitrification,and will lay the foundation of propagation and further genetic transformation for A. mongolicus.