Response of Arabidopsis Thaliana Seeds to Simulated Galactic Cosmic Rays
Abstract
One of the major concerns for long-term exploration missions beyond the Earth's magnetosphere, is radiation risks. These risks arise primarily from solar energetic particles (SEPs) and galactic cosmic rays (GCRs). With the goal of manned Mars exploration, the production of fresh food during long duration space missions is critical for meeting astronauts' nutritional and psychological needs. However, the biological effects of space radiation on plants have not been sufficiently investigated and characterized. This comprises a significant knowledge gap in terms of future NASA interplanetary missions and for establishing permanent inhabited bases.This pilot study is to evaluate the effect of simulated GCRs on Arabidopsis thaliana seeds using the NASA Space Radiation Laboratory (NSRL) facility at Brookhaven National Lab (BNL). The imbibed Arabidopsis seeds were exposed to two simulated GCR scenarios of combined ions including protons, helium, oxygen, titanium, and/or iron ions. The exposures were conducted acutely or at a low dose rate over a 4 hr time period. Some seeds were also exposed to individual high-LET ions (protons, helium, or titanium ions). Control and irradiated seeds were then transferred to a hydroponic system for growth within an environmentally controlled chamber with light intensity at 150 _mol?m-2?s-1. Six days after planting, morphological parameters were measured to evaluate radiation induced damage in the seedlings. Simulated GCR induced transcriptomic changes in 10 day Arabidopsis seedlings were also investigated using the same GCR scenarios mentioned above.Exposure to simulated GCRs or individual high-LET ions had no impact on the germination rate of both control and irradiated seeds. However, the morphological changes of the seedlings cultured from irradiated seeds were found to be dose- and ion quality-dependent, with heavier ions causing more severe damages. Transcriptomic profiles were significantly altered in the seedlings exposed to charged particles. Estimate hits/tracks per imbibed seed, root meristem and shoot meristem regions in a mature Arabidopsis embryo were also determined. More experiments need to be performed to complete the study using more dose- and time-points and to explore the mechanisms underlying heavy ions induced damage in Arabidopsis and other model plant organisms, especially those that have been identified as potential candidate crops for astronaut consumption and have been or will be grown on ISS.
- Publication:
-
42nd COSPAR Scientific Assembly
- Pub Date:
- July 2018
- Bibcode:
- 2018cosp...42E3845Z