中文摘要：

比较研究了SJ-8返回式卫星留轨舱微重力条件与地面三维回转模拟微重力条件下青菜生长与发育情况．研究发现空间微重力条件下青菜开花过程需要大约18h，明显长于地面对照5h左右．回转器模拟实验结果表明，改变重力影响了花瓣的伸展与发育及花粉的产量，回转条件下花粉细胞中的微管排列明显不同于静止对照．细胞骨架受到干扰可能是改变重力条件下花粉产量降低的原因之一．本研究首次报道了在空间飞行试验中成功地采用了显微实时图像技术观察植物的开花过程，并获得了从花蕾到开花结束各阶段清晰的图像．

英文摘要：

Plants have usually evolved under the surface gravity and have acquired the ability to gravistumili to regulate their growth and development. Space experiments show that the plant morphogenesis and growth responses are highly influenced by the gravity level. In the present study, flower and pollen development of Brassica parachinese under microgravity on board the Chinese S J- 8 recoverable satellite and under simulated microgravity on a 3D clinostat condition, respectively, were studied. Flower opening is due to the rapid growth and the movements of petals, which are accompanied by a high rate of cell expansion. The period of flower bud development and opening in space were about 18 h significantly increased in comparison with 5 h under 1 g control conditions. The experimental results of the 3D clinostat rotation also showed the similar results, that plants under clinostat rotation produced flowers with smaller petals and shorter stamens in comparison with the usually controlled plants, but no other attributes were apparently affected. In this case, significant reduction of the pollen was also observed in the flowers. The influences of altered gravitv on the arrays of microtubules in pollen cells during microspore nuclear migration and the asymmetrical mitosis were also observed. Based on our knowledge, the present space experiment is the first one to use the live imaging analysis to study the influence of the microgravity condition on the flower expansion and opening.