Xylem
Explanation
Vascular plants possess a specialized transport system consisting of complex permanent tissues known as vascular tissues. These tissues are responsible for the conduction of water, minerals, and organic nutrients throughout the plant body.
Analysis of Options:
- Xylem: This tissue is primarily responsible for the transport of water and dissolved mineral salts from the roots to the stems and leaves. The flow of materials in the xylem is unidirectional (upward from roots to the aerial parts), driven largely by transpiration pull and root pressure.
- Phloem: This tissue is responsible for the translocation of organic nutrients (photosynthates like sucrose) from the leaves (source) to storage organs or growing parts (sink). The transport in phloem is multidirectional (bidirectional).
- Parenchyma: This is a simple permanent tissue involved in functions such as photosynthesis, storage, and secretion, but it is not the primary tissue for long-distance transport.
- Collenchyma: This is a simple permanent tissue that provides mechanical support and flexibility to growing parts of the plant. It does not conduct water or minerals.
Key Takeaway: In vascular plants, Xylem conducts water and minerals unidirectionally, whereas Phloem translocates food materials multidirectionally.