~(12)C~(6+)重离子辐照大葱的细胞学和RAPD分析

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。

CYTOLOGICAL EFFECTS AND RAPD ANALYSIS OF Allium fistulosum L.IRRADIATED BY ~(12)C~(6+) HEAVY IONS

Cytological effects and RAPD analysis of root-tip cells of Allium fistulosum L., the dry seeds were irradiated by()~(12)C~(6 ) heavy ions,were studied.Micronucleus and chromosomal aberration observed in the root-tip cells showed that obvious "linear rise" trend was in the frequency of micronucleus,multi-micronucleus and total chromosomal aberration.But a "U-formed" trend was observed only in the chromosomal aberration frequency.At the same time,RAPD analysis revealed()~(12)C~(6 ) heavy ions exerted great effect on DNA variation of Allium fistulosum L..Flawing bands,increasing bands and the ones with different transport ratios were observed in amplified bands of 28 selected primers.The DNA variation rate for 30,90 and 180Gy treatments was 29.91%,41.05% and 22.14%,respectively.This study also found that high micronucleus frequency and chromosomal variation lead to high lethality,resulting in low DNA variation rate in the survived plants which seeds were irradiated with high doses.