Question

In the absence of nucleus how are the functions of a sieve tube maintained?

Answer 1

he phloem is the tubes located to the outer edge of the tree, lie just underneath the bark. It is made up of cells named sieve tube members, companion cells and parenchyma cells.

The nutrients travel through the sieve tube members, which do not contain a nucleus, since their function is to move the nutrients. A nucleus would just get in the way and hinder the traveling of the nutrients. The function of the companion cells is to take over metabolism for the sieve tube members. Companion cells apparently function with the enucleate sieve-tube elements and die when they break down.