Localization of Nucleic Acid Synthesis in Root Meristems

Adenine-8-C114 was supplied to roots of Vicia faba and Allium ascalonicum and its incorporation into DNA was studied from autoradiographs of hydrolysed sections. These roots have a quiescent centre to the meristem where the cells do not synthesize DNA and probably, therefore, play no part in the construction of the root. The boundary between the quiescent centre and the central cap initials is clearly defined and this suggests that there is as little cell interchange between the histogens as there is in roots with visibly discrete histogens.