Species of RNA synthesized during early germination in the radicle of the lentil embryo

Abstract

RNA synthesis is activated in cells of the plant embryo very soon after the start of imbibition by the seed. This study was undertaken to determine whether synthesis of one particular RNA or all the major RNA species was initially activated in the radicle of lentil embryos (Vicia lens). Two different methods were used after incorporation of radioactive precursor to identify the newly synthesized RNA species. First, RNA was extracted and analyzed using gel electrophoresis, gel filtration, affinity chromatography and base composition analysis. The second method was to localize the labelled RNA molecules within cells using autoradiography of sections of embryonic radicles. The data indicate that newly synthesized heterogeneous nuclear RNA and possibly messenger RNA, transfer RNA, 5S ribosomal RNA and precursor of ribosomal RNA are detectable 3 h after the start of imbibition of the decoated embryo and before completion of initial water uptake. It is concluded that synthesis of all major species of RNA is simultaneously initiated in the radicle of the germinating embryo.