. A mature sieve tube differs from a vessel
A: In lacking a functional nucleus
B: Absence of lignified walls
C: Being nearly dead
D: Lacking cytoplasm
- A mature sieve tube is a stack of vertical cells and its lateral walls have perforated sieve plates because it serves as phloem’s main conducting element.
- It does not have lignin in its wall.
- And they retain protoplast during differentiation but nucleus is absent.
- While vessels are dead elements of xylem that conducts water. It lacks nucleus and cytoplasm.
- Vessel’s secondary walls are thick because of lignin deposition.
Final Answer :
Hence, the correct option is B, i.e. Absence of lignified walls.