The First Appearance of Polyploid Nuclei in Primary Roots of Two Diploid Angiosperms

In Anchusa capensis, where the polyploid divisions are restricted to a particular time and place in germination, cytophotometric analysis showed that the polyploid cells arise at the time of conversion of the globular-shaped embryo to the heart-shaped embryo. In Spinacia oleracea, where the divisions occur throughout the growth of the root, these polyploid cells do not arise during embryogenesis but during germination and subsequent growth.