Do sieve tube cells have any extrachromosomal circular DNA at maturity?
This ref. says that the plastids and mitochondria are still intact.
Found by searching for &quot;sieve cell development&quot;
Neuberger, D.S., Evert, R.F. Structure and development of sieve cells in the primary phloem ofPinus resinosa . Protoplasma 87, 27–37 (1976). https://doi.org/10.1007/BF01623956
https://link.springer.com/article/10.1007/BF01623956