Wood is xylem, specifically secondary xylem.
According to the provided information, wood is identified as secondary xylem. This means that wood tissue is derived from the vascular system of plants responsible for transporting water and minerals. Let’s break down what this implies:
Understanding Xylem
Xylem is a vascular tissue in plants. Its primary function is to transport water and dissolved minerals from the roots to the rest of the plant. Here’s how it does this:
- Water Transport: Xylem's structure, largely composed of dead cells, creates continuous pathways for water to move upwards, a process driven by transpiration (water evaporation from leaves).
- Structural Support: Additionally, the woody nature of xylem provides structural support to the plant, allowing it to grow taller and withstand external pressures.
Understanding Phloem
Phloem, on the other hand, is another type of vascular tissue. Its role is entirely different:
- Sugar Transport: Phloem transports sugars produced during photosynthesis from the leaves to other parts of the plant, such as roots, stems, and developing fruits.
- Living Cells: Unlike xylem, phloem is mainly composed of living cells. These cells form pathways for the translocation of sugars.
Wood: Specifically Secondary Xylem
The reference material explicitly mentions that wood is **secondary xylem** consisting largely of dead cells involved in the transport of water and minerals as well as support. Thus, wood is not phloem, but a specialized form of xylem. Secondary xylem is generated by lateral meristems, which contribute to the growth in width of stems and roots. In contrast, primary xylem is generated by apical meristems and involved in height growth.
Key Differences Summarized
Here's a table summarizing the differences between xylem and phloem:
| Feature | Xylem | Phloem |
|---|---|---|
| Primary Function | Water and mineral transport; support | Sugar transport |
| Cell State | Mostly dead cells | Living cells |
| Direction of Transport | Upward from roots | Bidirectional (mainly from leaves) |
| Wood Composition | Secondary Xylem is the core component | Not involved in wood production |
Therefore, to be absolutely clear, wood is specifically secondary xylem and not phloem.
