Xylem Cells

In a plant, the water and mineral ions which are absorbed by the roots need to be transported up to the rest of the plant. They do this by travelling through a series of tubes called the xylem.

Diagram of a plant. The roots are shown underground, then there is a main stem with several shoots coming off it with leaves on them. At the top of the stem are some flowers. A blue line with arrows on it shows the xylem carrying water and mineral from the roots up to the rest of the plant. There is also a yellow line to show something called the phloem, which carries the products of photosynthesis from the leaves to the rest of the plant.

The xylem, shown in blue in this diagram, carries water and mineral ions from the roots up to the rest of the plant. Image: Xylem and phloem diagram.svg by Nefronus on Wikimedia Commons (CC BY-SA 4.0 - creativecommons.org/licenses/by-sa/4.0/deed.en).

The xylem will be covered in more detail later in the course when we look at transport in plants. For now, we will just focus on the cells that make up the xylem and their adaptations.

Microscope image of a cross section of a plant root. The image contains many circular cells packed together. They have been treated with a stain that colours the cell walls. Most of the cells have green cell walls, but there are a group cells in the centre with red cell walls. These are the xylem cells. The xylem cells are very large cells and they are arranged in the shape of a cross. No cell contents are visible in any of the cells in the image.

Microscope image of a cross section of a plant root. The cells have been treated with a stain that colours the cell walls. The xylem cells are the ones in the centre that form a cross shape. Their cell walls have been turned red by the stain. Image: Xylem Stained.jpg by Nicholas.H.Hale on Wikimedia Commons (CC BY-SA 4.0 - creativecommons.org/licenses/by-sa/4.0/deed.en).

The function of a xylem cell is to transport water and mineral ions.

Adaptations of xylem cells

A diagram of a xylem cell is shown below:

Labelled diagram of a xylem cell, showing that it is a hollow dead cell with no cytoplasm or other contents, it has no end walls and it has lignin in its cell wall.

A xylem cell

The adaptations of xylem cells include the following:

AdaptationHow it enables a xylem cell to carry out its function of transporting water and mineral ions.
It is a hollow, dead cell with no cytoplasm or other contents.This allows water and mineral ions to flow through it easily.
It has no end walls.This enables it to join together with other xylem cells to form a continuous tube for water and mineral ions to flow through.
It has a substance called lignin in its cell wall.The lignin in the cell wall strengthens the cell to prevent it from collapsing. It also helps to waterproof the cell to prevent water from leaking out.

Flashcards

Flashcards help you memorise information quickly. Copy each question onto its own flashcard and then write the answer on the other side. Testing yourself on these regularly will enable you to learn much more quickly than just reading and making notes.

1/5

What is the function of a xylem cell?

2/5

What adaptations does a xylem cell have that enable it to carry out its function?

3/5

How does being a dead, hollow cell enable a xylem cell to carry out its function?

4/5

How does having no end walls enable a xylem cell to carry out its function?

5/5

How does having lignin in its cell wall enable a xylem cell to carry out its function?

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