Testing the limits of survivability in space is the primary focus in astrobiological research. Although a number of previous studies have examined terrestrial life survival in an extraterrestrial environment, only a few have investigated how life systems respond to high doses of alpha cosmic ray, the main component of cosmic rays. We used respiration and photosynthetic rates as indicators of the vital signs of the lichen Caloplaca flavovirescens, which is a symbiotic life form including fungi and algae. Our experiment demonstrated that the photosynthetic rate decreased with increased helium-beam doses, whereas the respiration rate was relatively unaffected. Specifically, under a helium-beam dose greater than 10 Gy, the respiration rate remained nearly constant regardless of further increases in the radiation rate. Our results indicate that the different metabolic systems of terrestrial life forms might exhibit different survival characteristics when they are in space.

中文翻译：

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高剂量氦束照射下地衣黄萎病菌的潜在存活率。

测试太空生存能力的极限是天体生物学研究的主要重点。尽管许多先前的研究已经研究了在地球外环境中的地球生命生存，但是只有少数研究调查了生命系统如何应对高剂量的α宇宙射线（宇宙射线的主要成分）。我们使用呼吸和光合作用速率来指示地衣黄萎病的生命体征，这是一种包括真菌和藻类在内的共生生命形式。我们的实验表明，光合速率随氦束剂量的增加而降低，而呼吸速率相对不受影响。具体地，在大于10 Gy的氦束剂量下，呼吸速率几乎保持恒定，而与辐射速率的进一步增加无关。