A simple conceptual model of CELSS (Controlled Ecological Life Support Systems) of a bioreactor in which fish graze on an alga was formulated and the major ecological processes were mathematically simulated. To obtain the basic parameters and validate the model, corresponding empirical data, consisting of grazing by Grinocheilus aymonieri on Spirulina platensis was performed. From the separate experimental data from the fish tank and the algal tank, the growth parameters (μmax and KCN) of S. platensis and the grazing parameters (μx and Kx) of G. aymonieri were calculated. This study focuses on the prediction of the succession of a system by establishing a set of nonlinear dynamic equations for the CELSS. Comparison with the continuous measurements from the two reactors showed that the model fitted well with the experiment results both for the fish succession and for the substrate change.

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This paper presents the results of study on a prototype design and its set up to measure plant water uptake under the influence of microgravity (μG). The results are summarized as follows: 1) A proposed prototype system smoothly functioned and was controlled throughout the flight. 2) Leaf temperature increased by 0.8-1.6°C during μG condition. 3) Water uptake rate rapidly dropped when the gravity condition changed into μG from. 4) The water uptake recovered as the gravity increased to 1.5G which created by the ascending flight following to the μG flight. Uptake rate change took place at the time of gravity change (high-G to /from μG) but it did not sustain and its relaxation time varied.

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Rates of ethylene emission, photosynthesis and transpiration of dwarf rice species were measured by using a closed-type chamber. Volatile organic compounds (VOCs) emitted from rice plants were identified with gas chromatograph mass spectrometry. Ethylene emission rate on plant basis increased with days after planting. The rate was highest at anthesis stage and then decreased. Ethylene emission rate was not greatly different among rice species. But, the rates of photosynthesis and transpiration of the dwarf rice species were much lower than those of Nipponbare which is widely grown in Japan. Dimethylsulfide and 3, 7-dimethyl-1, 6-octadien-3-ol were major VOCs emitted from rice plants. 3, 7-dimethyl-1, 6-octadien-3-ol was emitted only when the rice plant had a damage such as leaf chlorosis by high air temperature. This result might indicate that measurement of VOCs in closed plant growth chamber such as Closed Ecology Experiment facility (CEEF) is a useful non-destructive method for plant growth diagnosis.

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Development of water recovery and recycling system in a plant growth chamber is most important challenge for plant cultivation under micro-gravity. In this paper, a water recycling system consisting of Peltier cooler unit and capillary fibrous mat for water transport is proposed as a suitable technology for small-scale closed plant growth chamber under micro-gravity. In the preliminary experiment, maximum water condensation rate by the fin of Peltier cooler unit was 100g/day. This value is not high enough to support water circulation in plant growth chamber when mature plants are densely grown. Water could be successfully transferred from the fin to the plant growth medium through the fibrous mat in the short-term experiment (144h). A long-term experiment is required to evaluate the system performance and stability. Key factors controlling water movement of the system, including hydraulic conductivity of the fibrous mat and medium and water condensation capacity of cooling fin, are discussed.

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To demonstrate the somatic effects of continued gamma-irradiation, the CF#T-JCL mice were raised and bred under the environment of continuous Co gamma-irradiation with a low dose-rate (5.7×10^-2Gy/22h-day) from conception until fully grown (90-160days old). The total dose accumulated was approximately 5.3-10.25Gy for each mouse of CF#1 males and females in the irradiated group. As a one of the criteria on growing process of mice, the changes of body weight, head-body length, and tail length were measured during the period from 70 to 160 days olds.
The increase on body weight, head-body length, and tail length were observed in mice of the control group according to their age from 70 to 160 days old. In the irradiated group, the pattern of growth in body weight, head-body length, and tail length showed the similar growth patterns as found in the controls, although the increase observed were always low values with compared to the same age of the control. Especially, the tail length were significantly shorter than in the controls, and the differences was clearly expressed in the tail coefficient (the ratio of tail and head-body lengths) of irradiated mice: the tail coefficient showed the value about 1.00 in all age groups of control whereas those of irradiated mice showed 0.9 in all age groups. From those results, the growth process of mice were affected under the condition of continuous gamma irradiation with low dose-rate throughout their whole duration of life.

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