Dynamac Corporation, Kennedy Space Center, FL 32899, United States.
Dynamac Corporation, Kennedy Space Center, FL 32899, United States.
Life Sci Space Res (Amst). 2022 Aug;34:37-44. doi: 10.1016/j.lssr.2022.06.001. Epub 2022 Jun 2.
Future space missions will likely include plants to provide fresh foods and bioregenerative life support capabilities. Current spacecraft such as the International Space Station (ISS) operate at 1 atm (101 kPa) pressure, but future missions will likely use reduced pressures to minimize gas leakage and facilitate rapid egress (space walks). Plants for these missions must be able to tolerate and grow reliably at these reduced pressures. We grew two lettuce cultivars, 'Flandria' a green bibb-type and 'Outredgeous,' a red, loose-leaf type, under three pressures: 96 kPa (ambient control), 67 kPa (2/3 atm), and 33 kPa (1/3 atm) for 21 days in rockwool using recirculating nutrient film technique hydroponics. Each treatment was repeated three times using a different hypobaric chamber each time. A daily light integral of 17.2 Moles Photosynthetically Active Radiation per day was provided with metal halide lamps set to deliver 300 µmol ms photosynthetic photon flux (PPF) for a 16 h photoperiod at 22 °C. Oxygen was maintained at 21 kPa (equal to 21% at 1 atm) and CO at 0.12 kPa (equal to 1200 ppm at 1 atm). Leaf area for 'Outredgeous' was reduced 20% and 38% at 67 kPa and 33 kPa respectively; shoot fresh mass was reduced 22% and 41% at 67 kPa and 33 kPa respectively when compared to control plants at 96 kPa. These trends were not statistically significant at P ≥ 0.05. Leaf area for 'Flandria' showed no difference between 96 and 67 kPa but was reduced 31% at 33 kPa; shoot fresh mass was reduced 6% and 27% at 66 kPa and 33 kPa respectively compared to 96 kPa. There were 10% and 25% increases in anthocyanin concentration at 66 kPa and 33 kPa compared to 96 kPa, potentially increasing the bioprotective capacity of the plant. Previous studies with other cultivars of lettuce showed slight change in growth across this range of pressures, suggesting responses may vary among genotypes, hypobaric exposure treatments, and / or environmental conditions. Collectively, the findings suggest further testing is needed to understand the effects of atmospheric pressure on plant growth.
未来的太空任务可能会包括植物，以提供新鲜食物和生物再生生命支持能力。目前的航天器，如国际空间站（ISS），在 1 个大气压（101 kPa）下运行，但未来的任务可能会使用降低的压力来最小化气体泄漏并促进快速撤离（太空行走）。这些任务中的植物必须能够在这些降低的压力下耐受和可靠生长。我们在岩棉中使用循环营养液膜技术水培法，在三种压力下（96 kPa（环境控制）、67 kPa（2/3 大气压）和 33 kPa（1/3 大气压）下）培养了两种生菜品种，'Flandria'一种是绿色 bibb 型，'Outredgeous'一种是红色松散叶型，共 21 天。每种处理重复三次，每次使用不同的减压室。每天提供 17.2 摩尔光合作用有效辐射的光积分，使用金属卤化物灯设置为每天 16 小时光周期下提供 300 µmol ms 光合光子通量（PPF），在 22°C 下。氧气保持在 21 kPa（相当于 1 个大气压下的 21%），二氧化碳保持在 0.12 kPa（相当于 1 个大气压下的 1200 ppm）。与 96 kPa 下的对照植物相比，'Outredgeous'的叶面积分别减少了 20%和 38%；茎鲜重分别减少了 22%和 41%。'Flandria'的叶面积在 96 和 67 kPa 之间没有差异，但在 33 kPa 下减少了 31%；与 96 kPa 相比，茎鲜重分别减少了 6%和 27%。与 96 kPa 相比，66 kPa 和 33 kPa 下的花色苷浓度分别增加了 10%和 25%，可能增加了植物的生物保护能力。以前对其他生菜品种的研究表明，在这个压力范围内，生长略有变化，这表明响应可能因基因型、减压暴露处理和/或环境条件而异。总的来说，这些发现表明需要进一步的测试来了解大气压力对植物生长的影响。
