氮离子束对小麦种子不同部位作用的突变效应

本文描述了荷能重离子束（^14氮^1 和^14氮^7 ）在作物改良上的应用。为了探讨离子束轰击小麦种子不同部位（例如：种皮,种胚和整粒种籽,包括胚乳、胚和种皮）后的不同反应,采用了不同能量的氮离子。轰击不同部位是通过改变离子能量来实现的。在这个研究中,我们选择了三种能量以达到轰击不同部位的目的,它们是超低能区的110keV,低能区的15．7MeV/u和中能区的72MeV/u.根据TRIM 91程序计算,它们在种子内的射程依次为0．44μm,0.61mm和9.6mm。所以,110keV的离子不能贯穿种皮,因为它的厚度72μm,只能极浅层注入种皮而不能触及胚细胞（称这种情况为轰击部位1）,15．7MeV/u的离子能够贯穿种皮并注入胚内（厚度约1mm),但不能进入胚乳（称这为轰击部位2）,72MeV/u的离子能从种子的胚部到顶部贯穿整个麦粒（麦粒长约7mm)（称这为轰击部位3）。上述三种能量的氮离子辐照了三个品种（定西24、88－12、82－579）的春小麦种子。而后进行了室内实验和大田培育,得到了50％出苗率时的剂量D50,统计了上述三个轰击部位下根尖细胞中的微核率及染色体畸变率,大田中产生了一些新的变异,例如增产（达百分之几十）,早熟（五天左右）,矮杆（低约20cm),抗（条锈）病,并且显示了轰击不同部位的突变频率与突变谱,还简略地讨论了三种情况的突变机理。

Mutagenic Effects of N Ion Beams on Different Sites of Triticum Aestivum L Seed

The applicati on of energetic heavy ion beams (~14N~1+ and~14N~7+) to cr op improvement is described in the paper. For the sake of exploring different re sponse of different sites (e.g. seed-coat, embryo, whole grain of wheat includi ng endosperm and former two) of wheat ( Triticum Astivum L ) seed to hit of t he ion beams, N ions with different energies were used. Hitting different sites was realized through changing ion energy. We chose three energies for the ions h itting different sites in the study. They were 110 keV in ultra-low energy regi on, 15.7 MeV/u in low energy region and 72 MeV/u in intermediate energy region. Their ranges in the wheat seed based on TRIM 91 calculation were 0.44 μm, 0.61 m m and 9.6 mm in turn. Therefore, the ions with 110 keV could not penetrate throu gh the seed coat (the coat thickness ～72 μm). It can superficially implant int o the seed-coat only code　and can not touch embryo cells (hitting site-1). The ions w ith 15.7 MeV/u can penetrate through the seed coat and i