Xylem Facts: Read About This Type Of Transport Tissue In Plants

Rajnandini Roychoudhury
Dec 15, 2022 By Rajnandini Roychoudhury
Originally Published on Apr 28, 2022
Fact-checked by Amatullah Gulbargawala
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cross section of stem plant tissue and under a light microscope

Plants derive their food and energy by themselves through the process of photosynthesis.

The uptake and transportation of water and nutrients from the roots to the tip of the shoots are done through xylem and phloem tissues in plants. The xylem tissue is the sole carrier of water and dissolved minerals required to nurture young plants and their old counterparts.

The word xylem was first put to use in 1858 by Carl Nageli. In flowering plants or trees, xylem tissues are found as tubular xylem vessels.

These remain hollow from within, allowing an easy passage of water throughout the trees. The xylem cell walls join together from end to end and form a hollow pipe-like structure. It remains bound by a hard division of cells.

Like the xylem, another vital plant tissue is the phloem that supports the tree with constant food and energy transport. Let us see how xylem present in trees or saplings help in their growth and maintenance.

Importance Or Significance Of Xylem

Xylem is present in all plant parts, starting from its roots to its stem and shoots.

Xylem cells bind together in vascular plants, forming the xylem tissue that becomes rigid and ultimately dies.

A chemical substance called lignin strengthens and hardens the thick cell walls of xylem vessels. It is because of this that ligneous plants usually stand tall and hard as lignified xylem cells give them support to stand erect.

The primary function of xylem cells is to transport water that the plant takes in from its roots from deep inside the soil. The tubular structure of the cells of the xylem in vascular plants allows the easy transportation of water upward, acting against gravity.

Unlike the phloem, xylem cells do not require any energy to carry the water to different plant parts. As transpiration results in the loss of water from the surface of the plants and their leaves, a natural vacuum gets created that pulls up the water from the root to different parts of the plant or tree.

The presence of both xylem and phloem is important at the site where active photosynthesis occurs in the plants. As water is rapidly lost through transpiration, the inability to replenish the water requirement will slow down the rate of photosynthesis, diminishing the production of nutrients for the plants.

Insufficient water at the surface of leaves will also malfunction the stomatal openings, causing reduced transpiration.

Different Types Of Xylem

Depending on the type of plant and its growing stage, the xylem vessel has different types of elements.

In young vascular plants, the tracheids act as the primary xylem cells that form a tubular shape with a narrow ending. Tracheids are commonly seen in juvenile conifers and ferns.

The primary xylem is found at the edges of roots, shoots, and flower buds. Apart from supplying water and dissolved minerals, they are responsible for making a tree grow taller and longer during its first growing season.

The secondary xylem emerges in trees that have secondary growth. Here the primary xylem is replaced by the secondary xylem made up of cambium. The lignin lining is the greatest in the secondary xylem. These trees emerge to grow wider and stronger with enlarged shoots and tree trunks.

Location And Size Of Xylem

Both xylem and phloem are located inside plants' roots, stems, leaves, and flower buds that are not visible to the naked eye.

Xylem is found in the central portion of the vascular bundle. It comprises a tubular structure consisting of the xylem elements tracheids, xylem vessels, and fiber.

In woody plants, the outermost wooden part comprises the dead xylem tissue that has been hardened by ligneous cells and supports the structure. While the phloem tissue can be found in the outer lining of the vascular bundles.

Together xylem and phloem make up the vascular bundles in plants and trees that aid in the passage of water and food to their aerial parts.

Xylem cells are microscopic, and their size differs due to plant-to-plant variations. The elongated tracheid cells join up to form the long connective tubular vessel enabling the free flow of water through capillary action.

As water is transported even to the tip of the tallest trees, the xylems also reach great heights.

As studies in plant sciences advanced, we got a clearer picture of how the plants absorb water and sucrose internally all by themselves. If the carriers of water and food, xylem, and phloem tissues are ruptured, the plants will eventually dry out of thirst and malnourishment, leading to their death.

FAQs

How does the xylem transport water?

Xylem transports water through its pipe-like vessels in an upward motion from the roots bound in the soil primarily through capillary action.

Which cell is not present in the xylem?

Since the phloem tissue is different from the xylem, the cells present in the phloem are not a part of the xylem. Cells like sieve cells and companion cells are not found in the xylem.

How many cells does xylem have?

Xylem is built up of four distinct cells out of which some are living while others are dead cells. The xylem parenchyma is composed of living cells. The tracheid, fibers, and xylem vessels are composed of dead cells.

How big is the xylem?

As the xylem runs through the entire length of the plant or tree, it extends from the innermost tip of the root to the outermost tip of its shoots.

Why is the xylem important?

Xylem is a vascular tissue that helps in the storage and transportation of water and water-soluble nutrients across the entire length and breadth of the plants, without which plants wouldn't survive.

What is xylem made of?

Xylem comprises elongated tracheid cells, shorter vessels, xylem fibers, and the thin xylem parenchyma.

What is unique about the xylem?

Water transportation through the xylem does not require any energy, even when traveling anti-gravitationally. The transpiration creates a deficiency at the stomatal openings that enable capillary action of drawing in more water from the plant's roots.

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Written by Rajnandini Roychoudhury

Bachelor of Arts specializing in English, Master of Arts specializing in English

Rajnandini Roychoudhury picture

Rajnandini RoychoudhuryBachelor of Arts specializing in English, Master of Arts specializing in English

With a Master of Arts in English, Rajnandini has pursued her passion for the arts and has become an experienced content writer. She has worked with companies such as Writer's Zone and has had her writing skills recognized by publications such as The Telegraph. Rajnandini is also trilingual and enjoys various hobbies such as music, movies, travel, philanthropy, writing her blog, and reading classic British literature. 

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Fact-checked by Amatullah Gulbargawala

Bachelor of Arts specializing in English, Bachelor of Education specializing in the Language Arts

Amatullah Gulbargawala picture

Amatullah GulbargawalaBachelor of Arts specializing in English, Bachelor of Education specializing in the Language Arts

Amatullah is a passionate student pursuing a Bachelor of Arts and Bachelor of Education from Ashoka College of Education. With a keen interest in literature, she has excelled in elocution competitions and is an accomplished writer. She has completed courses like "History of English Language and Literature", "Introduction to Western Political Thought and Theory", and "Development of Soft Skills and Personality". In her free time, Amatullah enjoys reading books and writing poetry.

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