实践八号卫星飞行环境中不同因素对小麦的诱变效应

Mutagenic Effects of Different Factors in Spaceflight Environment of Shijian-8 Satellite in Wheat

以实践八号育种卫星1×g离心机、铅屏蔽室和卫星舱内同时搭载处理的3个小麦品种为材料,分别分析同一飞行环境下空间辐射、空间微重力和空间综合环境作用对小麦的损伤特点,比较研究其对小麦品种的诱变效应。结果表明,空间综合因素处理抑制了小麦轮选987和新麦18当代(SP1代)的苗期生长,而对周麦18没有显著影响,空间辐射单因素处理只对轮选987有显著的抑制作用,而空间微重力对3个品种的抑制作用都不显著;成熟后3种处理对各农艺性状的影响都不存在显著差异。3个小麦品种SP2代均出现株高、穗长、千粒重等多种表型性状突变;轮选987和新麦18都表现空间综合环境因素诱发的突变频率高于其他2个单一因素,而空间微重力的突变效应最小。在新麦18空间综合因素处理的群体中,还发现了叶片条纹状白化突变体(0.48%)并可以遗传到后代。上述结果证实,在空间条件下宇宙射线和微重力的共同作用具有累加的效应,宇宙射线是产生变异的主要因素,空间微重力的单独作用也可以导致变异的产生。

Space environment mainly consisted of cosmic rays and microgravity is a kind of complicated mutagen, and has been used for plant mutation induction and breeding. In the recoverable satellite Shijian-8 that was launched for breeding purpose on September 9, 2006, seeds of three wheat （Triticum aestivum L.） cultivars, Lunxuan 987, Xinmai 18, and Zhoumai 18, were loaded. In the 1×g centrifuge, 300 seeds of each variety were treated with space cosmic rays （CR-E）, and in the lead screen container and the satellite capsule, 500 seeds of each cultivar were treated with microgravity （Mg-E） and comprehensive factors of space environment （SPc-E）, respectively. The treated seeds were germinated at room temperature and transplanted in the field after vernalization, the inhibition effects of the three treatments were evaluated and the mutagenic effects on wheat were compared. In the SPc-E treatment, growth of seedlings was significantly inhabited in the first generation （SP1） of Lunxuan 987 and Xinmai 18, whereas no significant effect was observed in the seedling growth of Zhoumai 18. In the CR-E treatment, only the growth of Lunxuan 987 seedlings was significantly inhibited. The Mg-E treatment had no significant effect on seedling growth in all the three cultivars. No significant variations were detected in main agronomic traits in the SP1 generation. In the SP2 generation, there were obvious mutations in phenotypes of the three cultivars, such as plant height, spike length and thousand-grain weight. In Lunxuan 987 and Xinmai 18, the highest mutation frequency was observed in the SPc-E treatment, followed by the CR-E treatment, and the lowest mutation frequency in the Mg-E treatment. A novel inheritable mutant of striated-albino leaf, with the frequency of 0.48%, appeared in the SP2 population of Xinmai 18 under the SPc-E condition. Among the three treatments, comprehensive factors of space environment induced the most frequent mutations of wheat, indicating the synergistic effect between cosmic rays and microgravity, while the single effect of microgravity was much lower than that of cosmic rays.