碳离子束辐照百脉根的当代生物学效应

Biological effects of carbon ion irradiations on M1 generation of Lotus japonicus

利用初始能量为80 MeV/u的碳离子束辐照百脉根(生态型:MG20)干种子,通过对M1代植株株高,干鲜重,光合色素含量的测定及DNA指纹图谱分析来研究高LET碳离子束辐照对百脉根M1代的相关生物学效应。结果表明,碳离子束辐照对百脉根的干鲜重、株高具有显著的抑制作用;叶绿素a、总叶绿素和类胡萝卜素含量均呈现出先升高后降低的趋势,叶绿素b的含量则表现出随剂量增加而逐渐降低的趋势;运用RAPD技术对辐照后百脉根的DNA指纹图谱进行分析,总多态性为15.483%,各辐照处理组之间的相似性系数在0.710-0.863之间,各处理组间的相似性系数与辐照剂量无明显的规律性,但是对照组与辐照组之间存有一定的差异性。综合分析表明:碳离子辐照百脉根干种子,具有明显的当代损伤效应,高LET辐照对百脉根具有严重的抑制生长效果,同时也对百脉根基因组DNA造成了一定程度的分子多态性差异。

To investigate the M1 biological effects of carbon ions on Lotus japonicas （MG20）, dry seeds were exposed to 80MeV/nucleon carbon ions at doses of 0 Gy, 20 Gy, 50 Gy, 150 Gy, 200 Gy and 300 Gy. The dry and fresh weight, and plant height of M1 seedlings were significantly inhibited by carbon ions. The contents of chlorophyll a, total chlorophyll, and carotenoid showed the same trend with an initial increase, followed by a decrease with each dose increment; meanwhile the content of chlorophyll b showed consecutive drops. By using a random amplified polymorphic DNA （RAPD） technique, the variations of genomic DNA fingerprints of the seedlings in control and treatment groups were examined. The 2,238 bands were amplified by using 59 primers, and 400 bands showed differences, and the total percentage ofpolymorphism was 15.483%. The genetic similarity coefficient among the control and treatment groups were 0.710--0.863, and there were no obvious correlations between the similarity coefficients and dosages, however, differences indeed existed between the control and treatment groups. In brief, all the results showed that exposure to carbon ions had obvious biological effects on both the development and genomic DNA of the M1 seedlings of Lotus japonicus.