sieve-tube member

A sieve-tube member is a living cell found in the phloem of vascular plants, specifically in angiosperms. These cells are crucial for transporting food, primarily sugars produced during photosynthesis, from the leaves to other parts of the plant.1

Key characteristics of sieve-tube members include:
* Enucleation: They lack a nucleus at maturity, with their nuclei fragmenting and disappearing.1
* Sieve Plates: Their end walls are perforated with sieve-like pores called sieve plates, which allow for the passage of nutrients between cells.1
* Companion Cells: Sieve-tube members are closely associated with companion cells, which are believed to support their metabolic functions.12

These specialized cells form sieve tubes, enabling the efficient movement of sugars throughout the plant.3