^(60)Coγ射线辐照对春兰‘雪山’的诱变效应

Mutagenic Effects of ^(60)Co-γ Irradiation on Cymbidium goeringii‘Xueshan'

本研究目的是通过辐射诱变创建春兰"叶艺"新种质,并研究其遗传机理。试验以不同剂量的^(60)Coγ射线对"叶艺"春兰品种‘雪山’带小芽植株进行辐照,对各处理植株、老芽、新芽的生长情况和性状进行观测,对新芽的‘叶艺’突变体进行了超微结构观察和遗传变异的ISSR分析。结果表明:辐照剂量为5 Gy,新芽‘叶艺’变异率达70.95%;辐射剂量为10 Gy,新芽‘叶艺’变异率达25.93%,新芽黄化苗变异率达7.14%。辐照剂量为20 Gy、30 Gy时,植株停止生长、老芽死亡,连续两年无新芽萌发。突变体出现斑缟艺、片缟艺、中斑艺、粉斑艺等高级艺,且生长性状稳定。叶片组织超微结构观察发现,正常植株、半边斑缟突变体叶片的绿色部位的叶肉细胞结构完整清晰,叶绿体数量较多,叶绿体内部片层排列有序且结构清晰;正常植株、突变体叶片的黄色部位的叶肉细胞中没有正常的叶绿体,没有基粒片层系统,只有少量细胞质、囊泡、嗜饿颗粒和线粒体;突变体的ISSR分析表明突变体DNA发生了变异。本研究的结果为高级"叶艺"春兰新种质的创建提供了参考,有很大的实用价值。

The purpose of this study was to innovate new germplasm about leaf variegation of Cymbidium goeringii through radiation, and study its genetic mechanism. In this research Cymbidium goeringii 'Xueshan' was irraclizted by^(60)Coγ-rays at different doses, and the irradiation effects on bud growth and character of treated pseudo-bulb, plumules, old bud were observed, and the ultra-structure of leaf color mutants were observed, and leaf color mutants were analysed by Inter-Simple Sequence Repeat. The results showed that the mutation rate of Leaf color was 70.95% with dose of 5 Gy; Leaf color mutation rate was 25.93% with dose of 10 Gy, and xantha mutants rate was 7.14%. The plant stop growing, plumules died a year later and no germination with dose of 20 Gy and30 Gy. The mutants including Mosaic leaves, Stripe Mosaic leaves, mottle leave, middle stripe leaves, and whole yellow leaves with green mottle, and so on, which showed the high level variegation and grew normal. Through observing the ultrastructure of the leaves, we found that the Mesophyll Cellular structure was integrated and there were more chloroplasts, lamella structure of an orderly and clear in the stroma in the green area; but in the yellow area of the leaves, there were no normal chloroplast and Grana lamella system in the chloroplast, and there were less cytoplasm, vesicle, osmiophilic droplets and mitochondria in the stroma. The analysis of ISSR showed that the DNA of Mutants happened genetic variation. The analysis of ISSR showed that the DNA of Mutants happened genetic variation. The results of this study provided reference to innovate new germplasm a bout high level leaf variegation of Cymbidium goeringii, which has great practical value.