红萍作为空间受控生态生命保障系统中的重要生物部件,为航天员提供O2和新鲜蔬菜,并吸收环境中CO2.本试验旨在弄清模拟微重力环境下红萍群体光合作用规律,为红萍生物部件的空间应用奠定基础.建立能模拟空间微重力效应的三维旋转式植物栽培装置,将红萍湿养在装置的受控密闭舱内,通过测定舱内O2和CO2浓度的变化来研究红萍群体光合作用的特征.试验结果显示,在模拟微重力环境下红萍净光合效率与光照强度成正相关,光照强度在7 000 lx时,单位能耗红萍放O2量和固定CO2量最大.红萍净光合效率还与密闭舱内大气CO2浓度环境成正相关,并与大气O2浓度环境成负相关.尤其在低O2浓度环境伴随高CO2浓度环境下,红萍的净光合效率较正常O2和CO2浓度环境的要高,这说明红萍光合放O2能力很强,有效促使密闭舱内O2和CO2浓度朝着有利于人生存的环境方向平衡,进而验证红萍的空间应用前景.%Azolla is an important biological component of the Controlled Ecological Life Support System (CELSS),because it can supply O2 and absorb CO2 from the environment,and can be used as fresh vegetable by the astronauts.The aim of this study is to clarify the canopy photosynthesis regular pattern of Azolla in simulated microgravity environment,and to lay the foundation of Azolla space's application.Azolla was moistly cultured in the controlled airtight cabin of 3D-rotary plant clinostat,which could stimulate space microgravity effect.The canopy photosynthesis characteristics of Azolla were studied by measuring the O2-CO2 concentrations in airtight cabin.The results showed that net photosynthesis efficiency of Azolla in stimulated microgravity environment had a positive correlation with illumination intensity.When illumination intensity was 7 000 lx,the amount of released O2and fixed CO2 by photosynthesis perunit energy consumption was the largest.Azolla net photosynthesis efficiency also had a positive correlation with CO2 concentration in cabin,but a negative correlation with O2 concentration.Azolla net photosynthesis efficiency was higher than that of normal atmosphere environment especially in an environment that was low in O2 and high in CO2.These results showed that Azolla had strong capacity of photosynthetic O2-release,which balanced the O2-CO2 concentration inside the cabin to aid the astronauts' survival,further prospect for Azolla space application.
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