Cell Ultrastructure of Mirovia macrophylla (Florin) Nosova (Pinopsida) from the Lower Cretaceous of Yakutia

The results of cytochemical and anatomical study of a leaf of the Lower Cretaceous conifer Mirovia macrophylla from the Lena Coal Basin in Yakutia are presented. For the first time, the presence of cells with preserved nuclei was revealed for an early Cretaceous conifer, although the DNA deoxyribose skeleton, serving as a target for the Schiff reagent during the Feulgen reaction, was not preserved in the nuclear chromatin. Chloroplasts with a thylakoid system were also found in the leaf cells, and inclusions were observed in the chloroplasts, the larger ones probably starch grains and the smaller ones plastoglobuli. In some cells, grooved globules were found, presumably tannins.