RADIO-ECOLOGY
13687
foliage consistently has higher K but lower Cs in the upper than in the lower
leaves. This would be in accord with a previous study (Rediske and Selders,
1953) which showed Cs to function as a relatively immobile element in bean
plants. Data from additional field samples of a greater number of plant species
are being accumulated at present with the hope of establishing more clearly the
differences between species in this respect and the significance of the sharp
differences between the older and youngerleaves.
The K and Cs-187 contents of field-collected Ieachates from Rongelap soil
have been shownto be greatest immediately following a dry period (Cole et al.,
1960). Since there are marked seasonal differences in precipitation at Rongelap
Atoll this may have a bearing on some of the results which have been discussed.
REFERENCES
1. Core, D. W., Gessex, S. P., and Herp, E. E. 1960. Tension lysimeter studies in glacial
2.
till and coral atoll soils. Proc. Soil Sci. Soc. Amer. (in press).
Jenny, H., Viamis, J., and Maatiy, W. E, 1950. Hilgardia 20: 1-8.
3. Nisuira, H., Romney, E. M., ALEXANDER, G. V., and Larson, K. H. 1960. Soil Science
89: 167-76.
4, RepisxE, J. H. and Sevpens, A. A. 1953. The uptake and translocation of cesium byplants.
U.S. Atomic Energy Commission, Tech. Information Service, HW-35174. 19 pp.