高剂量^(60)Co-γ射线辐照对澳洲坚果种子的诱变及致死效应

Mutagenic and Lethal Effect of High Dose ^(60)Co-γ Ray Irradiation on Macadamia Seed

在前期低剂量辐照试验的基础上,分别用剂量为300、600、900、1200、1500 Gy(2011年)和400、500、700、800 Gy(2012年)较高剂量的60Co-γ射线对4个品种的澳洲坚果种子进行了辐照,剂量率为10 Gy/h。结果表明,随着辐照剂量的增加,所有品种的发芽速率显著减慢,部分处理在播种后12周才开始发芽,且发芽率显著降低;辐照后的幼苗表现出茎干分叉、根系变短、第一对真叶消失、茎干矮化粗壮、叶片畸形等性状;不同品种的致死剂量和适宜诱变剂量也有明显差异,‘云澳57’和‘云澳58’的60Co-γ射线致死剂量均为800 Gy,‘云澳51’的致死剂量为900 Gy,‘云澳41’的致死剂量最低,为700 Gy;经致死剂量及高于致死剂量的射线辐照后,澳洲坚果种子仍可以正常裂壳和萌芽,但其芽点会逐渐变色直至死亡;4个品种的60Co-γ射线适宜诱变剂量分别为:‘云澳57’500 Gy,‘云澳51’700 Gy,‘云澳41’400 Gy,‘云澳58’300 Gy。

Based on the results of low dose 60Co-γ ray irradiation experiment,the seeds of four macadamia cultivars ‘ YunMac 57＇,‘ YunMac51＇,‘YunMac 41＇ and ‘YunMac 58＇ were inadiated by 60Co-γray at 300,600,900,1200,1500 Gy （in 2011） and 400,500,700,800 Gy （in 2012） with the dose rate of 10Gy/h.The results indicated that the seed germination of macadamia were significantly inhibited by 60Co-γ ray irradiation,some seeds began to germinate after seeding for 12 weeks.Seedlings after being irradiated showed the following properties：stem branching,root system becoming shorter,euphylla disappeared,dwarfed stem and leaf malformation.The lethal dose and appropriate mutation dose were different among different cultivars.The lethal dose of ‘ YunMac 57＇ and ‘ YunMac 58＇ were 800 Gy,and ‘ YunMac 51 ＇ was 900 Gy,and ‘ YunMac 41＇ was 700 Gy.The seeds which were iraadiated by lethal dose or higher dose began to germinate,but the shoots gradually died.The appropriate mutation dose of four macadamia cultivsrs were that ‘ YunMac 57＇ was 500 Gy,‘ YunMac 51＇ was 700 Gy,‘ YunMac 41＇ was 400 Gy and ‘ YunMac 58＇ was 300 Gy.