EFFECT OF IONIZING RADIATION ON MICROSPOROGENESIS IN PINUS RIGIDA MILL
A cesium/sup 137/ (9500 curies) source was placed in a natural pitch pine-oak forest at the Brookhaven National Laboratory Beginning on November 22, 1961, the forest was exposed to gamma rays during 20 hours each day. Pinus rigida trees were exposed to radiation levels ranging from a high of 960 r/day to a level of normal background radiation. Microsporangiate strobili were collected and evaluated at regular intervals to follow the effects of gamma radiation on the cytology of microsporogenesis. In addition, mature pollen of Pinus rigida and Pinus strobus were exposed to acute gamma radiation for a period of 16 hours from a cobalt/sup 60/ source of approximately 3200 curies at levels ranging from 1 to 300 Kr. Trees receiving 82 r/day and higher were unable to resume cell division and differentiation during the spring of 1962, while microspore mother cells were formed on trees receiving 75 r/day. At 56 r/day meiosis with subsequent formation of tetrads took place, and the highest level at which viable microspores were collected was 11 r/day. A slight reduction in the length of the strobili was observed at 0.4 r/day, and at 3.7 r/day they were significantly shorter than the controls. The percentage of cells with visible chromosome aberrations increased with an increase in exposure: 0.4 r/day = 1%; 7 r/day = 2%; 11 r/day = 12%; and 17 r/day = 76%. Pollon abortion increased with an increase in radiation, and at 7 r/day, approximately 50% of the pollen grains were aborted. At 3 to 5 r/day, germination in vitro was reduced to 50% of the controls. Pollen tube length was not related to exposure. Mature pollen of Pinus rigida and Pinus strobus was able to grow normal pollen tubes in vitro after exposure to 300 Kr. Illustrations of the various observations are given, and the results are discussed in relation to physiological and genetic implications. (auth)
- Research Organization:
- Yale Univ., New Haven. School of Forestry, CT (US) Brookhaven National Lab., Upton, NY (US)
- DOE Contract Number:
- AT(30-1)-2755
- NSA Number:
- NSA-18-013443
- OSTI ID:
- 4083839
- Report Number(s):
- BNL-6991
- Resource Relation:
- Other Information: Orig. Receipt Date: 31-DEC-64
- Country of Publication:
- United States
- Language:
- English
Similar Records
EFFECT OF IONIZING RADIATION ON FOREST TREES--ITS GENETIC AND CYTOLOGICAL IMPLICATIONS. Progress Report, June 1, 1961-May 31, 1962
PREDICTION OF THE SENSITIVITY OF PLANTS TO CHRONIC GAMMA IRRADIATION