Biological effects of high-LET particles on corn-seed embryos in the Apollo-Soyuz Test Project--Biostack III experiment.

Abstract

High-LET particle hits in embryos of Zea mays corn seeds, flown as part of Biostack III in the Apollo-Soyuz Test Project, were determined via plastic nuclear track detectors. Based on etched particle-track measurements, 41 embryos were hit in seed layer 1 which contained 80 seeds, and 49 hits occurred in layer 2 which contained 79 seeds. The mean LET value and range of atomic numbers of recorded hits is, respectively, 210 +/- 57 keV micrometers -1 and 9 < or approximately Z < or approximately 26. Detailed analysis of one particular seed showing marked growth anomalies revealed two hits in the central region of the embryo. These two hits had LET values in the region of 100-150 keV micrometers-1, and Z > or approximately 20.