An Endogenous Growth Pattern of Roots Is Revealed in Seedlings Grown in Microgravity
An Endogenous Growth Pattern of Roots Is Revealed in Seedlings Grown in Microgravity
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DOI：
10.1089/ast.2011.0699
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发表时间：
2011-10-01
期刊：
影响因子：
4.2
通讯作者：
Kiss, John Z.
中科院分区：
文献类型：
--
作者：
Millar, Katherine D. L.;Johnson, Christina M.;Kiss, John Z.
在植物中，敏感和选择性的机制已经进化成感知和响应光和重力。在航天实验中，我们研究了微重力对拟南芥(Landsberg)生长发育的影响。这些研究是在2010年4月执行STS-131任务期间，利用航天飞机中层甲板区域的生物罐研究硬件系统进行的。幼苗在黑暗条件下生长在金砖四国硬件的培养皿中的营养琼脂上，然后用多聚甲醛、戊二醛或RNAlater固定在飞行中。虽然长期目标是研究肌动蛋白细胞骨架在重力感知中的作用，但在本文中，我们重点分析在微重力下发育的幼苗的形态。虽然之前的航天研究指出了乙烯气体积累对形态的有害影响，但在用金砖四国系统生长的幼苗中没有观察到这种影响。航天试验的种子发芽率为89%，地面对照的种子发芽率为91%，两种条件下的幼苗生长情况相当。然而，太空育苗的根在总体生长模式上(与地面对照相比)表现出显著的差异，因为它们向一个方向倾斜。此外，在飞天植株中，下胚轴形成了更多的不定根。我们的假设是，植物的内源反应导致根部扭曲，这种默认的生长反应在很大程度上被地球上正常的1g条件所掩盖。
In plants, sensitive and selective mechanisms have evolved to perceive and respond to light and gravity. We investigated the effects of microgravity on the growth and development of Arabidopsis thaliana (ecotype Landsberg) in a spaceflight experiment. These studies were performed with the Biological Research in Canisters (BRIC) hardware system in the middeck region of the space shuttle during mission STS-131 in April 2010. Seedlings were grown on nutrient agar in Petri dishes in BRIC hardware under dark conditions and then fixed in flight with paraformaldehyde, glutaraldehyde, or RNAlater. Although the long-term objective was to study the role of the actin cytoskeleton in gravity perception, in this article we focus on the analysis of morphology of seedlings that developed in microgravity. While previous spaceflight studies noted deleterious morphological effects due to the accumulation of ethylene gas, no such effects were observed in seedlings grown with the BRIC system. Seed germination was 89% in the spaceflight experiment and 91% in the ground control, and seedlings grew equally well in both conditions. However, roots of space-grown seedlings exhibited a significant difference (compared to the ground controls) in overall growth patterns in that they skewed to one direction. In addition, a greater number of adventitious roots formed from the axis of the hypocotyls in the flight-grown plants. Our hypothesis is that an endogenous response in plants causes the roots to skew and that this default growth response is largely masked by the normal 1 g conditions on Earth.