米老排优树组培技术体系优化研究

Optimization of the tissue culture technology system of Mytilaria laosensis trees

【目的】建立米老排(Mytilaria laosensis)优良单株组培再生体系,为今后其无性化推广提供技术支撑。【方法】以米老排优树基部半木质化萌芽为外植体,采用丛芽发生途径,通过初代腋芽诱导、继代增殖培养、生根培养等过程,研究筛选最适的外植体采集时间、继代及生根培养的基本培养基以及植物生长调节剂的种类及浓度配比等。【结果】10月采集的外植体诱导效果最好,存活率为32.38%;米老排腋芽诱导最适配方为MS+6-BA 0.5 mg/L+NAA 0.02 mg/L,诱导率为100%,萌发时间为4.07 d;最适增殖培养基为MX(改良WPM)+6-BA 1.0 mg/L+NAA 0.05 mg/L,增殖系数达4.94,芽生长旺盛;最适生根培养基为MX+NAA 0.3 mg/L,生根率100%,平均根数13.18,根生长健壮,移栽成活率可达92.3%。【结论】米老排外植体诱导成活率与取材地点、时间相关,广东地区10月的米老排外植体材料最佳;在使用MS基本培养基增殖系数低的情况下,改用MX(改良WPM)培养基能够显著提高米老排增殖继代倍数;本研究还对米老排诱导培养基、增殖培养基、生根培养基进行了优化,有助于建立米老排优树组培体系,有效提高组培质量和效率。

【Objective】Mytilaria laosensis is an evergreen,broad-leaved tree with a wide range of suitable habitats and good economic and ecological protection.The seedling is mostly used for cultivation.Grafting and cutting techniques are still experimental,and few reports on tissue culture techniques exist.Therefore,it is of great significance to establish an efficient tissue culture technology system for M.laosensis and to provide technical support for promoting its clone in the future.【Method】With the semi-lignified bud at the base of the superior tree as explants,through the processes of primary axillary bud induction,secondary proliferation culture,rooting culture,the optimal explant collection time,the basic breeding and rooting culture medium,and the type and concentration ratio of plant growth regulator were studied.【Result】There were significant differences in the effect of different sampling times on the induction of M.laosensis.The best induction of explants was collected in October 2022,with a survival rate of 32.38%.Treatment with different hormone concentrations significantly affected the time required for bud germination and the growth status of explants.The optimal formula for axillary bud induction was MS+6-BA 0.5 mg/L+NAA 0.02 mg/L,the induction rate was 100%,and the germination time was 4.07 d.The selection of different basic mediums significantly affected the proliferation of M.laosensis.MX medium had the highest average shoot length(4.47 cm)and the largest proliferation coefficient(4.41),respectively,which were significantly higher than those of other basic media(1/2 MS,MS,DKW,WPM),and the proliferation buds grew strongly,increased quickly and had a good effect.Different hormone types and treatment concentrations significantly affected the proliferation and rooting effects of M.laosensis.The optimal breeding medium was MX(modified WPM)+6-BA 1.0 mg/L+NAA 0.05 mg/L,and the proliferation coefficient reached 4.94.The buds grow vigorously.The optimal rooting medium was MX+NAA 0.3 mg/L,the rooting rate was 100%,the average root number was 13.18,root growth was robust,and the transplanting survival rate reached 92.3%.【Conclusion】The induction survival rate of M.laosensis explants was related to the location and time of material collection.October was the best time to collect explant material in Guangdong.In the case of a low proliferation coefficient of the MS basic medium,switching to an MX(modified WPM)medium could significantly increase the proliferation succession factor.Then,the induction medium,breeding medium,and rooting medium were optimized,which helped establish the tissue culture system of the superior tree of M.laosensis and improved the quality and efficiency of the tissue culture.