In order to explain the effect of water tolerance of 60 Co-γradiation on the seed germination of Bromes , polyethylene glycol (PEG-6000 ) was used to simulate water stress ,The seeds of Bromes are used as materials ,using germination box filter paper germination .the effects of different 60Co-γ radiation on the seeding growth、cell membrane permeability、osmotic adjustment and the activity of protective enzymes were studied .The results showed that :10％ PEG was the best stress concentration in the seed germination period of Bromes .Low dose radiation to improve the root of the seed water absorption capacity ,and promote the water content of seedling ,there by promotion seedling growth ,high-dose radiation is inhibited .But the relative conductivity content was positively correlated with the radiation dose ,the radiation dose gradually increased ,the destruction of the cell membrane is enhanced .The contents of proline ,soluble sugar and soluble protein were negatively correlated with the radiation dose .Low dose radiation could promote the osmotic adjust-ment of substance and maintain normal physiological metabolism .With the increase of radiation dose ,the protective en-zyme activities of Bromes were all increased first and then decreased ,which indicated that low dose radiation could pro-mote the free radical scavenging ability of Bromes ,and the high dose had inhibitory effect .Low dose radiation can pro-mote promotes its ability of scavenging radicals of Bromes ,while the high dose has inhibitory effect .Thus ,the low dose of 60 Co-radiation (50～100 Gy ) to promote the growth of Bromes and protected the cell membrane by the decrease of relative conductivity .At the same time ,there is no increase in osmotic regulation and antioxidant enzyme activity to adapt to the water stress environment Inhibition ,the degree of damage to a minimum .%为了解60 Co-γ射线辐射对无芒雀麦种子幼苗耐旱性的影响,试验利用聚乙二醇(PEG-6000)为渗透介质模拟水分胁迫,以无芒雀麦种子为材料,采用发芽盒滤纸萌发,研究不同剂量60 Co-γ射线辐射对无芒雀麦幼苗生长、细胞膜透性、渗透调节物质和保护酶活性的影响.结果表明:10％PEG为无芒雀麦种子萌发期的最佳胁迫浓度.低剂量60 Co-γ辐射提高种子的根系吸水能力,促进幼苗的含水量增加,从而促进种子的幼苗生长,高剂量辐射则具有抑制作用.相对电导率含量与辐射剂量呈正相关,随辐射剂量逐渐升高,对细胞膜的破坏性增强.脯氨酸、可溶性糖、可溶性蛋白含量变化均与辐射剂量呈负相关,低剂量辐射可以促进渗透调节物质含量的积累,进而维持正常的生理代谢.随着辐射剂量的增加,无芒雀麦幼苗的保护酶活性均呈现先升后降趋势,说明低剂量辐射促进无芒雀麦幼苗清除自由基的能力,而高剂量具有抑制作用.低剂量60 Co-γ射线辐射(50～100 Gy)促进无芒雀麦幼苗的生长,且通过相对电导率的降低对细胞膜起到保护作用.同时,无芒雀麦幼苗可通过体内渗透调节物质及抗氧化酶活性的增加来适应水分胁迫环境.
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