枸杞抗炭疽病菌毒素愈伤组织变异体的离体筛选及其防御酶活性研究
Selection of Resistant Calli of Lycium barbarum to Colletotrichum gloeosporioides in vitro and Its Changes in Activity of Defensive Enzymes

以枸杞炭疽病菌粗毒素液作为选择剂，将体细胞无性系变异与辐射诱变相结合，对宁夏枸杞主栽品种“宁杞1号”的叶片胚性愈伤组织进行辐射诱变和筛选，以期获得稳定的抗炭疽病细胞变异系。结果表明，以半致死剂量的60Co γ对枸杞叶片诱导出的胚型愈伤组织进行辐照处理，将其恢复增殖后，采用多步正选择法结合加压与去压交替的筛选方法，筛选到了抗性愈伤组织变异体，其在不同粗毒素浓度胁迫下，其鲜重增长均高于对照组，而且在离开选择因子继代培养4代后，仍保持获得的抗性。分析抗性系与抗病相关的防御酶的活性表明，无论有无粗毒素胁迫，抗性愈伤组织变异体的PAL、POD和PPO酶活性均高于对照愈伤组织；在粗毒素胁迫下，随着粗毒素浓度的增大，3种酶活性基本呈先升高后降低的趋势，抗性变异系3种酶活性的上升幅度较对照组要大，而PAL和POD活性的下降速度较对照亲本系小，说明抗性变异系通过增强与抗病性相关酶的活性，来加强同植物防卫有关的物质代谢。
For obtaining stable cell mutant of Lycium barbarum. resistant to Colletotrichum gloeosporioides, the disease resistant mutant selection system was established by the integral application of theγ-ray irradiation and somaclonal variation techniques. The results showed some stable cell mutants resistant to the toxin of C. gloeosporioides were obtained after the calli induced with the leaves of Ningqi No.1 (L.barbarum cv. Ningqi 1) were treated by the dose value of LD50 of 60Co γ-ray irradiation and then selected by using multi-step screening system and interval selected method. The fresh weight increment of the resistant lines was higher than that of controls at different concentrations of crude toxin, and they could remain resistance to toxin after they were subcultured four times successively apart from selective factor. Furthermore, changes of activity of defensive enzymes (PAL, POD and PPO) in mutant and original callus were investigated after treated by different concentrations of crude toxin. The results demonstrated that the activity of three disease resistance-related enzymes in resistant calli was higher than that of parent calli whether or not treated with crude toxin. As the concentration of crude toxin increased, the activity of three defensive enzymes both increased then decreased, the range of the activity variation of three enzymes in variant cell lines was lower than those of the parent