Hydroids
Hydroids are vascular cells seen in bryophytes. Mature hydroids are thin, colourless, long structures that contain water. They do not have a living protoplasm. They act as conducting tissue (hydrome) that transports minerals and water from the soil. They are similar to the xylem tracheids seen in vascular plants.
Leptoids
The hydroids are surrounded by living cell structures called leptoids. The leptoid bundles carry nutrients and sugar molecules. These are also conducting cells seen in some bryophytes. They are similar to the sieve elements of phloem. The mature leptoids have inclined cell walls with minute pores and nuclei.
Difference between Hydroids and Leptoids
Hydroids |
Leptoids |
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They are mineral and water-conducting cells seen in some bryophytes. |
They are sugar and nutrient conducting cells seen in some bryophytes. |
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Hydroids are similar to the xylem tracheids. |
Leptoids are similar to the sieve elements in the phloem. |
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They are the innermost cell structures of the stem. |
They are the cell bundles that surround the hydroids. |
Also Read: Difference between Xylem and Phloem
Frequently Asked Questions
What is a stereid?
A stereid is a plant cell that has a thick cell wall. It provides mechanical support to the cell. These stereids are usually present in hydroids and are absent in most leptoid cells.
What are tracheids and vessels?
They are the water-conducting components of the xylem tissue. These are tubular cells that also provide mechanical support to the plant. Most angiosperms use vessels as their tracheary element.
What are sieve elements?
They are specialised cells that are vital for the functioning of phloem. They aid in conducting sugar molecules over long-distance. The two types of sieve elements are – sieve tubes and sieve cells.
Also see: Difference between Tracheids and Vessels
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