Revision 1
March 19, 1998
by Radiation, Science, and Health, Inc.,
Edited by J. Muckerheide

1.3
Animal & Plant Biology

1.3.3
Plants

"A significant observation was that there was no difference in the frequency of somatic mutations in the stamens following exposures at dose-rates of 0.03 mR/hr (control), 0.08 mR/hr, 0.16 mR/hr, 0.32 mR/hr, 0.65 mR/hr and 1.30 mR/hr for 280 days. The total exposure at the end of 280 days was 0.201R (0.201 cGy) for the control and 8.736 R (8.736 cGy) for the maximally exposed groups therefore the somatic mutation frequencies for the control and the and the maximally exposed groups were 2.77 +/- 0.706 and 3.63 +/- 0.819 respectively. It is evident that a ‘linear, no threshold’ relationship between the frequency of somatic mutations in the stamen hairs of Tradescantia and chronically accumulated total dose of 8.74 cGy does not exist. Mutations in the stamen hairs form a sensitive system. There was however, a demonstrable mutagenic activity associated with the content of alpha-emitting radionuclides in the plant tissue"

"The observation that the plants which accumulate large amounts of radionuclides have considerable meiotic abnormalities, but the seeds, which they set, give rise to almost normal plants suggests that certain mechanisms to sieve out genetically imbalanced gametes/zygotes must be operating. In this regard, the occurrence of apoptosis in plant systems (Greenberg et al 1994, Mittler and Lam 1995) is of relevance for further studies in the plant communities of HBRA. Similarly, the significance of apoptosis as a part of biological defense mechanism of mammalian systems is being increasingly appreciated"