In which zone of root growth would a sieve tube member likely lose its nucleus?

In the zone of differentiation, specialized cells undergo changes that prepare them for their specific functions in the plant. Sieve tube members, which play a critical role in transporting nutrients within the phloem, lose their nucleus during this process. This loss is significant because it allows for the creation of a more efficient transportation system, as the absence of a nucleus provides more space for the cytoplasm, facilitating transport functions. The differentiation phase is crucial for cells to become proficient in their specific roles, like conducting photosynthates in the case of sieve tube members.

In contrast, the other zones do not involve the same specialization. In the zone of cell division, cells are actively dividing and have fully functional nuclei. The zone of elongation involves growth as cells increase in size, and while they are developing, they still maintain their nuclei. The zone of maturation involves the final structural adjustments but does not specifically relate to the loss of the nucleus in sieve tube members. Thus, the zone of differentiation is the correct context for understanding why sieve tube members lose their nucleus.