[Cell cycle phases: determination of G1, S e G2 by fluorometry (author's transl)]

The G1, S and G2 phases of the cell cycle in Allium cepa root tips were determined in Acriflavin--Feulgen--stained material. Pigeon erythrocyte nuclei were employed as standard for DNA dry mass determinations. Micro-interferometric and fluorometric measurements gave the average of 77,1. 10(-12) g for the G1 nuclei from the root tips.