Kiss J Z
Department of Biology, University of Mississippi, University, MS, USA.
Plant Biol (Stuttg). 2014 Jan;16 Suppl 1:12-7. doi: 10.1111/plb.12031. Epub 2013 Jul 25.
While there have been numerous studies on the effects of microgravity on plant biology since the beginning of the Space Age, our knowledge of the effects of reduced gravity (less than the Earth nominal 1 g) on plant physiology and development is very limited. Since international space agencies have cited manned exploration of Moon/Mars as long-term goals, it is important to understand plant biology at the lunar (0.17 g) and Martian levels of gravity (0.38 g), as plants are likely to be part of bioregenerative life-support systems on these missions. First, the methods to obtain microgravity and reduced gravity such as drop towers, parabolic flights, sounding rockets and orbiting spacecraft are reviewed. Studies on gravitaxis and gravitropism in algae have suggested that the threshold level of gravity sensing is around 0.3 g or less. Recent experiments on the International Space Station (ISS) showed attenuation of phototropism in higher plants occurs at levels ranging from 0.l g to 0.3 g. Taken together, these studies suggest that the reduced gravity level on Mars of 0.38 g may be enough so that the gravity level per se would not be a major problem for plant development. Studies that have directly considered the impact of reduced gravity and microgravity on bioregenerative life-support systems have identified important biophysical changes in the reduced gravity environments that impact the design of these systems. The author suggests that the current ISS laboratory facilities with on-board centrifuges should be used as a test bed in which to explore the effects of reduced gravity on plant biology, including those factors that are directly related to developing life-support systems necessary for Moon and Mars exploration.
自太空时代开始以来，虽然已经有大量关于微重力对植物生物学影响的研究，但我们对低重力（小于地球标准重力1g）对植物生理和发育影响的了解非常有限。由于国际空间机构已将载人探索月球/火星作为长期目标，了解月球（0.17g）和火星重力水平（0.38g）下的植物生物学非常重要，因为植物很可能是这些任务中生物再生生命支持系统的一部分。首先，回顾了获得微重力和低重力的方法，如落塔、抛物线飞行、探空火箭和轨道航天器。对藻类趋重力性和向重力性的研究表明，重力感知的阈值水平约为0.3g或更低。国际空间站（ISS）最近的实验表明，高等植物的向光性在0.1g至0.3g的水平上会减弱。综合这些研究表明，火星上0.38g的低重力水平可能足以使重力本身不会成为植物发育的主要问题。直接考虑低重力和微重力对生物再生生命支持系统影响的研究已经确定了低重力环境中影响这些系统设计的重要生物物理变化。作者建议，当前配备机载离心机的国际空间站实验室设施应作为一个试验台，用于探索低重力对植物生物学的影响，包括那些与开发月球和火星探索所需生命支持系统直接相关的因素。
