Difference Between Tracheids And Vessels

Tracheids

Tracheids are elongated cells present in the xylem of vascular plants which serve in the transportation of water and mineral salts. One of the two types of tracheary elements is tracheids and the other is vessels (which will be described further). Tracheids and Vessels have similar functions but we can spot the difference between tracheids and vessels. One is Tracheids that do not have perforation plates like vessels. Later in this article, a tabular chart will be used to differentiate between tracheids and vessels. 


Talking about Xylem, it is one of the two types of transport tissues in vascular plants and phloem being the other. Xylem’s function is to transport water from roots to stems and leaves, it can also transport various nutrients.


Vessels

Vessels in plants can be defined as elements found as one of the cell types found in xylem which is the water conducting tissue of plants. Vessels are found in angiosperms, also known as flowering plants but are absent from the most gymnosperms like conifers. Vessels transport water, nutrients and minerals through the plant and are vascular tissues.


So, it can be said that the xylem vessels and tracheids are the main elements that play major roles in water conducting in different kinds of plants. Both are tracheary elements and highly specialized cells that are devoid of protoplast when they mature. Also, are non-living which are elongated in shape with lignified cell walls. However, they differ in their diameter and the efficiency in their functions. More differences between tracheids and vessels are detailed below.


(image will be uploaded soon)


Difference Between Tracheids and Vessels

Characteristics

Tracheids

Vessels

Definition

These are part of xylem which are elongated narrow tube-like dead, empty cells having thick and lignified walls and large cell cavities.

These are cylindrical tubular in structure and form a row of cells that are placed end to end. The cells in vessels are connected with the help of plates with pores which help in moving water upward.

Examples

These are found in all vascular plants such as the wood of ferns as well as gymnosperms like pines. 

These are only found in angiosperms such as Mango trees.

Function

Xylem Tracheids function: Its conduction of water and minerals helps in providing mechanical support to the whole plant. 

Xylem Vessels function: Its conduction of water all the way from root to the leaves help in providing mechanical support to the plant. 

Origin

These originate from a single cell.

These elements originate from a longitudinal file of cells and produce continuous tubes.

Diameter

Tracheids consist of a narrow lumen.

Vessels consist of a wide lumen.

Cells 

These are imperforated cells.

These are perforated cells.

Efficiency

These are inefficient in the conduction of water as they lack perforations.

These are efficient in water conduction as are perforated cells.

Cell wall thickness

They consist of thin cell walls.

They consist of highly thickened cell walls.

Cross-section

They contain polygonal cross-sections.

These consist of circular cross sections.

Length

They have average 1 mm length, which is comparatively shorter to vessels.

Vessel cells are longer, which is about 10 cm in length, much longer than tracheids.

Structure of Ends

These have conical end walls.

These have diagonal or transverse sidewalls.

Connection

These are connected laterally to each other.

These are connected from end to end.

Surface/Volume Ratio

These consist of a high surface/volume ratio.

These consist of a low surface/volume ratio.

Air Embolism

Tracheids help in preventing air embolism due to their high adhesion strength in the narrow tube.

These do not help in preventing air embolism.


Similarities Between Tracheids and Vessels

Having discussed the differences between tracheids and vessel, let’s now know about their similarities which are listed below :

  • Tracheids and vessels, both are the two components of the xylem.

  • Both the elements are tubular cells.

  • Both of these are dead at maturity since they possess secondary lignification.

  • Both tracheids and vessels are present in both primary and secondary xylem.

  • Both tracheids and vessels function in water conduction along the stem and also provide mechanical support to the plant.

FAQs (Frequently Asked Questions)

1. What are Xylem and Phloem?

Ans. Xylem and phloem are the two types of transportation tissues in vascular plants that are responsible to transport water, sugars and other nutrients around a plant. Xylem is considered as complex, dead and permanent tissues that carry nutrients and water whereas phloem is a soft permanent tissue that transports food and other organic material produced by the green plants, through photosynthesis by the leaves of plants. Tracheids and vessel elements are the two different elements of Xylem whereas companion cells, sieve tubes, phloem fibres and phloem parenchyma are the various elements of Phloem.

2. What are Tracheids?

Ans. Tracheids are highly specialized non-living cells that are present in the xylem of plants. These elements help in water conduction and provide mechanical support to the plants. They are not perforated and are found in seedless vascular plants and gymnosperms such as cedar, pine, ferns, mosses, etc. These are present in the form of a single elongated cell with pointed ends and thickened cell wall. Another element of xylem is phloem that also helps in conduction more efficiently than tracheids as these have perforated in nature.