西藏虎头兰高效植株再生体系的研究

In vitro culture and highly efficient plant regeneration system of Cymbidium tracyanum

为建立西藏虎头兰(Cymbidium tracyanum)的高效快速繁殖体系,该研究以野生西藏虎头兰种子为外植体,通过分析不同基本培养基和植物激素配比对原球茎诱导、增殖和分化的影响,以及光照时间和培养温度对试管苗生长的影响,筛选出适宜西藏虎头兰植株高效再生的条件。结果表明:适宜西藏虎头兰生长的基本培养基为1/2 MS;种子萌发和原球茎诱导的最适培养基为1/2 MS+1.0 mg·L^(-1)6-BA+0. 5 mg·L^(-1)NAA,培养50 d后,有95.00%的种子发育成原球茎;原球茎增殖的最适培养基为1/2 MS+2.0 mg·L^(-1)NAA,培养30 d,增殖倍数为4.25;原球茎的最适分化培养基为1/2 MS+2.0 mg·L^(-1)NAA+60 g·L^(-1)土豆泥+0.5g·L^(-1)活性炭,培养10 d,不定芽发生率为98.33%,培养40 d,幼苗生根率为94.67%;试管苗在温度20℃、光照时间12 h·d^(-1)、光照强度2 000 lx的条件下培养,苗长势好,叶片生理性焦尖发生率仅为3.33%;以腐殖土作为栽培基质,试管苗的移栽成活率为97.78%。该研究结果为保护西藏虎头兰野生资源和工厂化育苗提供了科学依据和技术支持。

In order to establish a highly efficient plant regeneration system, Cymbidium tracyanum was selected as explant to screen out the conditions to regenerate with highly efficiency, by evaluating the effects of basic medium and hormone combination on the plant regeneration of C. tracyanum , and the effects of illumination time and culture temperature on the growth of plantlets were also studied. The results were as follows: The optimum basic medium for C. tracyanum growth was 1/2 MS. The optimal medium for protocorm induction was 1/2 MS+1.0 mg·L^-1 6-BA+0.5 mg·L^-1 NAA, 95.00% of the seeds developed into the protocorms after cultured for 50 d. The optimal medium for protocorm proliferation was 1/2 MS+2.0 mg·L^-1 NAA, the maximum proliferation multiple of protocorm reached 4.25 after cultured for 30 d. The optimal medium for protocorm differentiation was 1/2 MS+2.0 mg·L^-1 NAA+60 g·L^-1 mashed potato+0.5 g·L^-1 acticarbon, the induction rate of indefinite bud was 98.33% after cultured for 10 d, the rooting rate was 94.67% after cultured for 40 d. In the process of plantlets subculture, temperature of 20 ℃, illumination time of 12 h·d^-1 and illumination intensity of 2 000 lx were suited for the growth of plantlets, the physiological scorch rate of leaf tip was 3.33%. Using humus as cultivation substrate, the transplanting survival rate of plantlets was 97.78%. This study provides an effective way for keeping good varieties of features and rapid propagation of C. tracyanum , at the same time, helps to solve some theoretical problems in factory production of C. tracyanum .