Studies On The Speed Setting Of Uniaxial Clinostat Simulating The Effects Of Microgravity

In this paper, force analysis is carried out to the tested samples on uniaxial clinostat with the fundamental principle of physics. The rule of speed setting for uniaxial clinostat simulating microgravity effects and a method to determine the minimum reponse time to gravity of tested samples are suggested from the theoretical viewpoint; A tested sample is selected to do experiments with different speeds on uniaxial clinostat. The minimal reponse time to gravity of the tested sample and the optimizing rule of speed setting can be obtained by comparing the theoretical results with the experimental ones.To simulate the microgravity effects with uniaxial clinostat, the speed of the clinostat should be constrained by two factors at least:on the one hand, the changing period of rotation must not less than the minimum response time to gravity of the sample. So, the tested sample can not feel the effect of gravity and achieve the effects of microgravity simulation. Thus, the rotational speed should be as fast as possible; On the other hand, the centrifugal force should not be too large. The centrifugal force is relevant to the rotational speed and radius. Only the centrifugal force acting on the tested sample is small enough, the conditions simulating microgravity experiments are valid. So, the rotational speed should be as slow as possible. Take the above two factors into account, we can determine the minimum and maximum rotational speeds in theory, so as to determine the range of totational speeds for uniaxial clinostat.We select vigna radiata as testing samples and observe the changes of their roots in macro phenotype and microscopic physiological indexes at different rotational speeds, From this, one can judge whether the results of simulating microgravity effect are available. The samples are divided into nine groups:1 group for control and 8 groups for rotational treatment. Selecting 8 vigna radiata seeds with near 5mm long in each group, make the rotational treatment groups rotate continusly for 24h under different selected speeds respectively, and make the control group static for 24h. Finally, we observe the rotational treatment groups in macro aspect (offset distance and offset angle of the root) and microscopic aspect (distribution of starch grains in root cell) respectively. Comparing these results with that of control group can optimize the rule of speed setting and determine the minimum response time to gravity of the sample.We hope that the rule of speed setting for uniaxial clinostat and the method to determine the minimum response time to gravity suggested in this paper can be helpful for the biological researchers who use uniaxial clinostat to simulate microgravity effects.