1971 年 36 巻 3 号 p. 529-533
Nucleolus organizers in meiotic prophase of Lilium longiflorum microsporocytes were studied with the electron microscope and found to be less electron-dense than the majority of the chromatin and the nucleolus. The structural units of the nucleolus organizers were observed to be loosely arranged fibrils, 75-125 A in diameter. This organization was interpreted as an intermediate stage in chromatin condensation, indicating decreasing synthetic activity, as was suggested by previous workers on mitotic nucleolus organizers.