NUKLEONIKA 2005, 50(4):161-166

Effects are described of internal exposure doses of ionizing radiation in above- and underground parts of test plants under natural conditions and in roots of Lepidium sativum L. from accumulated ¹³⁷Cs under laboratory conditions. In the region most contaminated after the Chernobyl accident, in the tested 10 plant species for ¹³⁷Cs ionizing radiation the internal exposure doses 3.5 times exceeded those in the Ignalina Nuclear Power Plant environment. Under laboratory conditions the effect of low internal (0.6–600 mSv) and external (40–5500 mSv) exposure doses from ¹³⁷Cs on garden cress, Lepidium sativum L. roots was, practically, the same. Both internal and external exposure doses stimulated the plant root growth by 12 and 33%, respectively. Different effect of external and internal exposure on the developing plant cells was observed by analyzing the results of morphometric investigations of the primary root cap cells of Lepidium sativum L.