As plants prepare their food, they have a specialized type of conductive cells that carry out the process of transportation in plants. Plants can mainly be divided into two types, based on their conductive system; vascular plants & non-vascular plants. Vascular plants are those plants which have specialized conductive cells, Xylem and Phloem, whereas non-vascular plants lack these tissues and get transportation using the simpler tissues. Xylem tissue is responsible for transportation of water from roots to the other parts of the plant while phloem tissue transports food from the leaves of the plant to the other parts. The xylem tissue mainly comprises of two type of cells; Tracheids, which are the long elongated cells, and Vessels, which are the shorter and wider cells. Tracheids are present in all vascular plants; in gymnosperms, they occur alone in the woody area of the plant while in angiosperms they are associated with vessels. On the other hand, vessels are typically found only in the angiosperms.
What are Tracheids?
Tracheids are the lignified and elongated cells situated in the layer of Xylem tissues; they are present in every of the vascular plant. In gymnosperms, tracheids are located in the woody area of the plant while in angiosperms, they are associated with the vessels. They are usually the large cells with the pointed ending with lacking the perforations. Their major function in the plants is the transportation of minerals and water and providing the mechanical support to the plant body. These cells are derived from the single individual cells and lack protoplasm as like vessels. Tracheids have the higher surface to volume ratio as compared to the vessels that is why they can resist gravity and have the ability to retain the water. These are imperforate cells, which have large pits that are less in number and have a narrow diameter as compared to the vessels.
What are Vessels?
Vessel elements are the lignified cells present in the angiosperm plants; they are surrounded by the parenchymal cell. These cells are situated in the Xylem of the plant are responsible for the transportation of sap from the roots to the other parts of the plant and give the required mechanical support to the plant body. These cells perform quite the similar function as tracheids do, although they are absent in gymnosperms, whereas tracheids are present both in angiosperms and gymnosperms. With wide diameter and perforations, vessels are comparatively the better transporter of water due to the presence of perforations. The longitudinal bundle of cells is divided into different portions to from these vessels that is why they vary in length. Even after dividing these vessels are associated with each other through the perforations, which makes them a tube-like structure that is wider regarding the diameter. These vessels are named according to their shapes due to the perforations, the one with simple perforation is called simple perforations, the vessel with ladder-like perforation is called scalariform perforation, the vessel with several round openings is called forminate perforation, and lastly, the vessel with the net-like pattern is called reticulate perforation.
Tracheids vs. Vessels
- Tracheids are the long elongated cells, whereas vessels are wider and shorter cells.
- Tracheids are present in all vascular plants; in gymnosperms, they occur alone in the woody area of the plant while in angiosperms they are associated with vessels. On the other hand, vessels are typically found only in the angiosperms.
- Tracheids have the higher surface to volume ratio as compared to the vessels that is why they can resist gravity and have the ability to retain the water.
- Tracheids are formed with the division of single individual cells, on the other hand, the longitudinal bundle of cells is divided to form vessels.
- Tracheids are imperforate cells, which have large pits that are less in number while vessels have smaller pits which are multiple in numbers.