Two types of vascular tissues, xylem and phloem, transfer food, nutrients, water and minerals from roots to leaves. With the help of tracheids and vessels, xylem tissue carries water and minerals from the roots to other areas of the plant. Tracheary elements are another name for these Xylem tissues.
Tracheid and vessel cells die at maturity, have lignified walls, and are found in both primary and secondary Xylem.
Vessels and Tracheids – Similarities
In a lot of aspects, the tracheids and vessels are comparable. Here are some examples of parallels:
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The complicated xylem tissue is made up of tracheids and vessels.
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Both aid in water conduction down the stem and provide mechanical support for the plant.
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Both cells have tubular structures.
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In both cells, secondary lignification is evident. When they reach adulthood, they die.
Tracheids and Vessels – Introduction
The two water-conducting elements found in the xylem are tracheids and vessels. In ferns and gymnosperms, tracheids are the primary conductors. Angiosperms are the only plants that have vessels. The tracheids have a smaller diameter than vessels. Perforation plates are also present at the ends of the cells in vessels. As a result, water conduction efficiency in vessels is higher than in tracheids. The plants’ mechanical strength is provided by both tracheids and vessels. The fundamental distinction between tracheids and vessels is their diameter and water conduction efficiency.
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.
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. |
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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. |
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Diameter |
Tracheids consist of a narrow lumen. |
Vessels consist of a wide lumen. |
|
Cells |
These are imperforated cells. |
These are perforated cells. |
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Efficiency |
These are inefficient in the conduction of water as they lack perforations. |
These are efficient in water conduction as are perforated cells. |
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Cell wall thickness |
They consist of thin cell walls. |
They consist of highly thickened cell walls. |
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Cross-section |
They contain polygonal cross-sections. |
These consist of circular cross sections. |
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Length |
They have an 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. |
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Structure of Ends |
These have conical end walls. |
These have diagonal or transverse sidewalls. |
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Connection |
These are connected laterally to each other. |
These are connected from end to end. |
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Surface/Volume Ratio |
These consist of a high surface/volume ratio. |
These consist of a low surface/volume ratio. |
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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. |