Question

Describe and explain the adaptations of xylem and how they are adapted for its function?

Answer 1

Adaptations of Xylem for its FunctionThe main purpose of the xylem is to transport water and minerals up the stem, from theroots to the leaves. In order for a xylem to carry out its functions successfully and efficiently, it musthave to be adapted.One of the main adaptations of the xylem is the ring of lignin that forms a spiral pattern around the xylem tube. Dueto the immense strength of the lignin, it helps to be asupportive structure for the plant, either woody or nonwoody. Furthermore the lignin prevents the walls of the xylemfrom collapsing under pressure, which would be caused by thehydrostatic pressure of the transpiration pull, and the rootpressure made from high pressure water being pushed up thexylem. Additionally lignin is waterproof, which means it willprevent any water from leaking out of the xylem (diffusing inand out), so that the maximum amount of water travels upthe plant to the leaves. Lastly, lignin is very rigid which helpsto keep the walls stiff, so that it can resist the strain of physical forces.Another adaptation of the xylem is it being made up of dead cells, which will enable it tocarry water through it, as, when it dies, it shrivels up causing the cell inside the cell wall to die andmean that it is hollow within the cell wall. When the cell dies, this means that the nucleus,cytoplasm, chloroplasts and mitochondria are all disintegrated to form a clear tunnel so that thewater is not impeded.A further adaptation of the xylem (tracheid) is the pits that form inthe walls of the xylem, which helps to transfer water from one tracheid toanother, which allows the water to move from side to side even though thereis waterproof lignin. The xylem transfers water so that the xylem walls dontcollapse in when water is being sucked up the stem of the plant. Also thereare pits in the xylem so that water can be transferred to neighbouring cellsnear the xylem that require water to stay turgid, and those needed tophotosynthesis so that it can produce glucose.Additionally, xylems have adapted by removing end walls of the cells(perforation plates), so that the open ends of the cells can join together toform a long, open, hollow tube. This then allows the water to move up a continuous column, withoutit having to diffuse by osmosis from one cell to another. As a result this means water is transportedquicker up to the leaves so that more photosynthesis can occur, as the hollow tube increases thesurface area to volume ratio. The perforation plates help to facilitate water movement in the xylem,meaning water can pass freely.

Answer 2

The vascular plant tissue xylem transfers water and nutrients from the soil to the stems and leaves.

About Xylem:

• Xylem is a vascular tissue found in plants that transports water and dissolved minerals from the roots to the rest of the plant while also providing physical support.
• Tracheary elements are specialized, water-conducting cells that make up xylem tissue.
• A mature woody stem or root is mostly composed of xylem cells.
• They are piled end to end in the plant's core, producing a vertical column that transports water and minerals received by the roots up the stem to the leaves.
• The tension caused by transpiration "pulls" water in the plant xylem, pushing the water upward in the same way as sucking on a straw draws water higher.
• As the top-most water is drawn toward the stomata, cohesion (water adhering together) causes additional water molecules to fill the gap in the xylem.

Xylem adaptations:

• The xylem cells have adapted to their role by losing their end walls, resulting in a continuous, hollow tube.
• They are reinforced by a chemical known as lignin.
• Lignin provides the plant with strength and support.
• Because xylem cells lack cytoplasm and end walls, they form a tube through which water may easily travel, allowing water transfer.

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