摘要:
To explore the effects of crude toxins from Colletotrichum gloeosporioides(C. gloeosporioides)on the growth of Dendrobium officinale Kimura et Migo(D. officinale),and to provide early basis for thescreening and cultivation of the resistant variants of C. gloeosporioides. Methods Seedlings of D. officinal werecultivated in MS medium added with different concentrations of the crude toxins from C. gloeosporioides. Theeffects of the crude toxin on the growth of seedlings were observed, and the optimum resistance -selectionthreshold was preliminarily screened. Results In the concentration range of 5% - 15%(volume fraction),crudetoxins from C. gloeosporioides increased the plant height,stem diameter,number of new bud,root number,and fresh mass of D. officinale,among which the effect of 5%(volume fraction)of crude toxins was the moststrongest. In the concentration range of 35% - 40%(volume fraction),crude toxins suppressed the plant height,leaf number,number of new bud,root number,and the fresh mass of D. officinale. When cultured with 20%(volume fraction)crude toxins, D. officinale was blooming, and the flowers appeared variation phenomenon.Conclusion The crude toxins from C. gloeosporioides have biological activity and certain toxicity,which can beconsidered as a selection agent instead of pathogenin in vitro to screen the resistant variant of D. officinale,butthe optimum resistance-selection threshold still needs further research.%[目的]探究胶孢炭疽菌粗毒素对铁皮石斛幼苗生长状况的影响,为铁皮石斛抗性突变体筛选和培育提供前期基础.[方法]添加不同浓度胶孢炭疽菌粗毒素的MS培养基对铁皮石斛幼苗进行培养,观察粗毒素对幼苗生长的影响,并初步筛选适宜抗性选择压.[结果]胶孢炭疽菌粗毒素浓度在5%~15%(体积分数)范围内,对铁皮石斛株高、茎粗、新增芽数、根数、鲜重的增长起促进作用,其中以浓度为5%(体积分数)时促进作用最为显著;粗毒素浓度在35%~40%(体积分数)范围内对铁皮石斛株高、叶片数、新增芽数、根数、鲜质量的增长起到抑制作用;粗毒素浓度在20%(体积分数)时,铁皮石斛出现开花现象,且花的形态出现变异现象.[结论]胶孢炭疽病菌粗毒素具有生物活性,且有一定的毒性,可以考虑代替病原菌作为离体筛选铁皮石斛抗炭疽病突变体的选择剂,但筛选铁皮石斛抗性突变体的抗性选择压还有待进一步研究.