Vessels
Explanation
Phloem is a complex permanent tissue responsible for the transport of organic food materials (photosynthates) from leaves to other parts of the plant. In angiosperms, phloem consists of four distinct elements: sieve tube elements, companion cells, phloem parenchyma, and phloem fibers.
Option Analysis
- Sieve tubes: These are long, tube-like structures arranged longitudinally and are the primary conducting elements in angiosperm phloem. Therefore, they are present.
- Companion cells: These are specialized parenchymatous cells closely associated with sieve tube elements, helping regulate their function. Therefore, they are present.
- Vessels: Vessels are long, cylindrical tube-like structures characteristic of xylem tissue in angiosperms. They are responsible for the conduction of water and minerals, not food. Therefore, they are absent in phloem.
- Phloem parenchyma: These are living parenchymatous cells present in the phloem of most dicotyledonous angiosperms, used for storage and lateral conduction. Therefore, they are present.
Key Takeaway: The fundamental difference in vascular tissue composition is that Xylem contains vessels and tracheids for water transport, while Phloem contains sieve tubes and companion cells for food translocation.