Cytological Effects of Aerospace Flight and ~(60)Co-γ-Rays Irradiation on the Seeds of Lactuca indica L

The experiment was carried out to compare the cytological effects induced by aerospace and 60Co-γ-rays irradiation on the root tip cells of Lactuca indica L. seeds treated by recoverable satellite and irradiation at different dose 60Co-γ-rays in the range from 0 to 30Gy, respectively. The results show that aerospace flight stimulated the cell mitosis, but 60Co-γ-rays irradiation inhibited cell mitosis. With the increased dosage of 60Co-γ-rays irradiation, mitosis rate decreased. Both aerospace and 60Co-γ-rays irradiation induced various aberrations in root tip cells, such as micronucleus, chromosome fragment, chromosome conglutination, lagging chromosome, dissociative chromosome and bridge. However, the aberration rate caused by aerospace environment was lower than that caused by 60Co-γ-rays irradiation. The higher dosage of 60Co-γ-ray applied, the higher rates of single micronucleus、mutil-micronucleus, and total chromosome aberration occurred.