Monje O, Bingham G E, Carman J G, Campbell W F, Salisbury F B, Eames B K, Sytchev V, Levinskikh M A, Podolsky I
Plants, Soils & Biometeorology Dept., Utah State University, Logan 84322-4820, USA.
Adv Space Res. 2000;26(2):303-6. doi: 10.1016/s0273-1177(99)00575-x.
The SVET Greenhouse on-board the Orbital Station Mir was used to measure canopy photosynthesis and transpiration rates for the first time in space. During the Greenhouse IIB experiment on Mir (June-January 1997), carbon and water vapor fluxes from two wheat (cv. Superdwarf) canopies were measured using the US developed Gas Exchange Measurement System (GEMS). Gas analyzers capable of resolving CO2 concentration differences of 5 micromoles mol-1 against a background of 0.9% CO2, are necessary to measure photosynthetic and respiratory rates on Mir. The ability of the GEMS gas analyzers to measure these CO2 concentration differences was determined during extensive ground calibrations. Similarly, the sensitivity of the analyzers to water vapor was sufficient to accurately measure canopy evapotranspiration. Evapotranspiration, which accounted for over 90% of the water added to the root zone, was estimated using gas exchange and used to estimate substrate moisture content. This paper presents canopy photosynthesis and transpiration data during the peak vegetative phase of development in microgravity.
和平号轨道站上的SVET温室首次用于在太空中测量冠层光合作用和蒸腾速率。在和平号上进行的温室IIB实验期间（1997年6月至1月），使用美国开发的气体交换测量系统（GEMS）测量了两个小麦（品种：超级矮秆）冠层的碳和水汽通量。要在和平号上测量光合作用和呼吸速率，需要能够在0.9%二氧化碳背景下分辨出5微摩尔/摩尔二氧化碳浓度差异的气体分析仪。GEMS气体分析仪测量这些二氧化碳浓度差异的能力在广泛的地面校准中得到了确定。同样，分析仪对水汽的灵敏度足以准确测量冠层蒸散量。蒸散量占添加到根区水分的90%以上，通过气体交换进行估算，并用于估算基质含水量。本文展示了微重力条件下发育高峰期冠层光合作用和蒸腾作用的数据。
