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xylem

Primary Information
Secondary Information

Definition

Xylem is a vascular tissue in plants that transports water and dissolved nutrients from the roots to the leaves. It is made up of long, hollow cells called tracheids and vessels.

Xylem is an important part of the plant's vascular system, which also includes the phloem. The phloem transports sugars and other organic molecules from the leaves to the rest of the plant.

Xylem is made up of four main types of cells: tracheids, vessels, parenchyma cells, and fibre cells. Tracheids and vessels are the most important xylem cells for transporting water. Parenchyma cells store water and nutrients, and fibre cells provide support.

Xylem is an essential part of plant life. It helps plants to get the water and nutrients they need to survive and grow.

How can the word be used?

The xylem transports water and dissolved minerals from the roots to the leaves.

xylem

Different forms of the word

Noun:

  • xylem (the vascular tissue in plants that transports water and dissolved minerals).
  • xyleme (British spelling of xylem).

Etymology

The word "xylem" comes from the Greek word "xylon" (wood). The first recorded use of the word "xylem" in English was in 1875.

Question

What is the difference between xylem and phloem?

AQA Science Exam Question and Answer

Question:

Describe the role of xylem in plant physiology and its function in the movement of water and minerals. Explain how the structure of xylem vessels supports its transport function.

Answer:

Xylem is a crucial tissue in plants responsible for transporting water, dissolved nutrients, and minerals from the roots to other parts of the plant. This process, known as transpiration, is driven by the movement of water molecules from an area of high concentration (root cells) to an area of low concentration (atmosphere), facilitated by the cohesion and adhesion properties of water.

The structure of xylem vessels is well-suited to support efficient water and mineral transport. Xylem vessels are composed of elongated cells called tracheids and vessel elements. These cells are dead at maturity, forming long, hollow tubes that create a continuous pathway for water movement. They are strengthened by lignin, providing structural support and preventing collapse under negative pressure.

Furthermore, the interconnectedness of xylem vessels enables capillary action, where water molecules adhere to vessel walls and are drawn upward through the plant. This capillary action, combined with transpiration and the cohesion of water molecules, creates a continuous flow of water from roots to leaves.