Plants, terrestrial radiation

Acute biological effects of the Chernobyl accident on local natural resources were documented by Sokolov et al. (1990). They concluded that the most sensitive ecosystems affected at Chernobyl were the soil fauna and pine forest communities and that the bulk of the terrestrial vertebrate community was not adversely affected by released ionizing radiation. Pine forests seemed to be the most sensitive ecosystem. One stand of 400 ha of Pirns silvestris died and probably received a dose of 80 to 100 Gy other stands experienced heavy mortality of 10- to 12-year-old trees and up to 95% necrotization of young shoots. These pines received an estimated dose of 8 to 10 Gy. Abnormal top shoots developed in some Pirns, and these probably received 3 to 4 Gy. In contrast, leafed trees such as birch, oak, and aspen in the Chernobyl Atomic Power Station zone survived undamaged, probably because they are about 10 times more radioresistant than pines. There was no increase in the mutation rate of the spiderwort, (Arabidopsis thaliana) a radiosensitive plant, suggesting that the dose rate was less than 0.05 Gy/h in the Chernobyl locale. 

Table 32.19 Radiation Effects on Selected Terrestrial Plants...

D. M. Hunten, Atmospheric evolution of the terrestrial planets. Science 259, 915-920 (1993) J. F. Kasting, Earth s early atmosphere. Science 259, 920-926 (1993) R. A. Berner, Atmospheric carbon dioxide levels over phanerozoic time. Science 249, 1382-1386 (1990) R. A. Berner, Paleozoic atmospheric CO2 importance of solar radiation and plant evolution. Science 261, 68-70 (1993). 

The geochemical balance of carbon changed dramatically during Devonian and Carboniferous times. At those times the main evolutionary radiation of terrestrial vascular plants occurred. These events flowed from the development of various parts of higher plants, such as roots, stems, leaves, and reproductive apparatus enabling the colonization of a new ecological niche. This colonization and accumulation of... 

M.M. Caldwell, A.H. Teramura, M. Tevini, J.F. Bornman, L.O. Bjorn, G. Kulan-daivelu (1995). Effects of increased solar ultraviolet radiation on terrestrial plants. Ambio, 24,166-173. 

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