Rhythmic increase in DNA content and incorporation of [(3)H]thymidine in the developing wheat embryo during seed germination.

The DNA content and incorporation of [(3)H]thymidine into DNA have been studied during the development of Triticum aestivum (L.) embryo at various stages of seed germination up to 102 h (18°C). The DNA content of the embryos increased in a rhythmic way, when superimposed on an increasing basal content of DNA from 12 h onwards of germination. A temporary depression in DNA content was observed before the peaks of cell division (which has earlier been published by the author). The peaks of [(3)H]thymidine incorporation coincided with the peaks of cell division.