Dormant cuttings of Salix nigra Marsh, were exposed to gamma radiation from a cobalt-60 source at a dose rate of 1110 roentgens (r) per minute. Exposure doses ranged from 50 r through 100 Kr with 100% mortality at 10 Kr. Low doses of ionizing radiation apparently stimulated growth, while higher doses progressively retarded growth. The growth of the staminate catkins was inversely proportional to total exposure dose (increased dose resulted in progressively decreased growth). Determination of growth rates at different intervals post-irradiation indicated recovery of the surviving fraction of the irradiated cuttings. At ninety days, the highest growth rate occurred at the highest surviving exposure dose. It was also noted that total RNA and protein concentrations were sensitive even to the lowest exposure doses. The effects of gamma radiation on development of viable pollen grains were scored on the basis of the aniline-blue (cotton blue) lactophenol test. Pollen grain viability was found to increase with increasing gamma radiation up to 100 r. Progressively lower pollen viability was recorded from 400 r up to 4 Kr.
Gehring, Roy Z.
"Effects of Gamma Radiation on Salix nigra Marsh Cuttings,"
Journal of the Arkansas Academy of Science: Vol. 39
, Article 11.
Available at: http://scholarworks.uark.edu/jaas/vol39/iss1/11