Abstract
In normal and tumorous tobacco calluses treated with hydroxyurea RNA synthesis was investigated with the use of NaH232PO4 as precursor and the method of fractionation on MAK columns. Low inhibitor concentrations show a specific action, and the influence of this compound on the RNA of the two tissues is different. In tumour tissue the population of the rapidly labelled RNA localized in region IV of the elution profiles exhibits remarkable resistance to hydroxyurea (HU). Moreover, disturbances of equilibrium between synthesis and degregation of heavier RNA, indicating inhibition of its degradation, are observed.