Effects of high temperature on RNA-synthesis during germination of maize (Zea mays L.)

Abstract

Maize seeds imbibing at high temperatyres (above 37°C) germinate poorly, and their embryos show a low rate of protein-synthesis. Extracts of embryos imbibing at normal and high temperatures were able to translate exogenous mRNA, and poly (A) RNA obtained from them stimulated polypeptide synthesis by reticulocyte and maize cell-free extracts.

Embryos imbibing at 41°C incorporated insignificant amounts of [³H] adenine into poly (A) RNA and high M_r rRNA. Autoradiography showed that little transcription occurred in these embryos. Chromatin remained aggregated throughout imbibition at this temperature.

The results suggest that synthesis of new mRNA is essential for germination to proceed. Poor germination of maize at high temperature is probably due to the inhibition of transcription.