中文摘要：

该研究表明，1Gy、10Gy和100Gy的α粒子注入拟南芥胚后，胚的发芽率均达96％以上，α粒子注入对胚生活力的影响体现在发芽势，照射1Gy发芽势呈升高趋势，剂量大于10Gy发芽势低于正常水平。主根长度的变化趋势与发芽势一致，100Gyα粒子注入使主根的重力敏感性降低，而在竖直的培养基上呈“S”型生长。Vc清除过氧化氢实验表明，100Gy的α粒子注入的拟南芥胚，在含0．2mmol／LVc的MS培养基上，根的重力敏感性恢复正常。α粒子注入引起的重力敏感性及根长等生理指标的变化与过氧化氢的产生有关。过氧化氢酶、丙二醛的含量随剂量的增加而增加，而SOD活性在100Gy时降低。该研究表明，α粒子注入可能通过诱导信号分子过氧化氢的增加，引起生理水平的变化。

英文摘要：

T Arabidopsis embryos were irradiated by 241^Am α-particles to 1, 10 or 100Gy to study the irradiation effects. The results indicated that germination percentages of embryos were not affected by the irradiation in the dose range. Germination speed of the 1Gy group was 11.4% higher than that of control, whereas germination speed of the higher dose groups decreased, with germination speed of the 100Gy group being about 29.3%. The irradiation effect on root length was similar to the germination speed. Moreover, root gravitropism of the 100Gy group became S-shaped curves. In a mechanism study, the root gravitropism recovered while cultured in an MS medium containing 0.2mmol/L Vc, which indicated that H2O2 might joined the process of gravitropism. Furthermore, during shooting period of the Arabidopsis, the content of MDA was detected and the activities of SOD and CAT were observed, and the CAT activity and MDA content increased with the dose, while SOD activity of the 100Gy group decreased by 12.6% compared with the control. The results indicate that the induced increase of H2O2 signal .molecules after the α-particle irradiation may be the mechanism of radiation physiological effects.