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用309、0和180Gy12C6+重离子辐照处理大葱干种子,研究其对大葱根尖的细胞学效应,并采用随机扩增多态性DNA(RAPD)技术初步分析了其变异类型。不同剂量12C6+的重离子照射能有效诱导大葱根尖细胞微核和染色体畸变。随着辐照剂量的增加,幼苗根尖细胞微核形成几率明显增大,微核率、多微核率和染色体总畸变率呈线性上升。但除去微核以外的染色体畸变率则呈U型变化。RAPD结果表明,大葱不同处理之间的DNA存在明显差异,所用35种引物中有28种出现了特异性条带,既有新增条带,又有缺失条带,还有迁移率的差异。30、90和180Gy剂量辐照引起的RAPD变异率分别为29.91%、41.05%和22.14%。结果发现高微核率和染色体变异过大会导致高致死效应,使得染色体总畸变率高的处理组在当代生长苗的DNA变异率变小。
The seeds of Welsh Onion were treated with heavy ion irradiation of 309, 0 and 180Gy12C6 + and their cytological effects on the root tips of Welsh Onion were studied. The variations of them were analyzed by random amplified polymorphic DNA (RAPD) technique. Different doses of 12C6 + heavy ion irradiation can effectively induce onion root micronucleus and chromosome aberrations. With the increase of irradiation dose, the chances of micronuclei formation in root tip cells of seedlings increased obviously, and the rates of micronucleus, micronucleus and total chromosome aberration increased linearly. However, except for the micronuclei, the rate of chromosome aberration was U-shaped changes. The results of RAPD showed that there was a significant difference in the DNA between the different treatments of Welsh Onion. Among the 35 kinds of primers used, 28 showed specific bands, including new bands, missing bands and differences in mobility. The mutation rates of RAPD caused by 30, 90 and 180 Gy doses were 29.91%, 41.05% and 22.14%, respectively. The results showed that high micronucleus rate and chromosomal aberrations caused by over-large lead to a high lethal effect, so that the total chromosome aberration rate of treatment groups in contemporary growing seedling DNA mutation rate becomes smaller.