Dry mass content in nuclei and cytoplasm during differentiation of the root cortex cells of Helianthus Annuus.

Dry mass content in nuclei and cytoplasm as well as its concentration during the growth and differentiation of the root cortex cells of Helianthus annuus were investigated by means of interference microscopy. Moreover, by incubation with radioactive thymidine, the endopolyploidization at the level of 4C was found to exist in this species. It was found that during the growth and differentiation of the root cortex cells, the average dry mass content in nuclei essentially does not increase, whereas its content in cytoplasm increases significantly. At the same time the progressive decrease of dry mass concentration takes place in both nuclei and cytoplasm. This drop is connected with their growth and results from the considerable hydratation of karyoplasm and cytoplasm.