Answer:
The odd one out in the given options is (d) Tracheids.
Step-by-step explanation:
Sieve tubes, companion cells, and phloem fibers are all components of the phloem tissue, which is responsible for transporting organic nutrients, such as sugars and amino acids, throughout the plant. On the other hand, tracheids are a type of xylem cell involved in water transport.
Sieve tubes are long, cylindrical cells found in the phloem tissue of flowering plants. They are responsible for transporting organic materials, primarily sugars, from photosynthetic tissues to non-photosynthetic parts of the plant. Sieve tubes have perforated end walls called sieve plates that allow for the movement of nutrients between adjacent cells.
Companion cells are closely associated with sieve tubes and provide metabolic support to them. They are connected to sieve tubes by plasmodesmata, which are small channels that allow for communication and transport between cells. Companion cells play a crucial role in maintaining the function and integrity of sieve tubes.
Phloem fibers, also known as bast fibers, are elongated cells that provide mechanical support to the phloem tissue. They have thick cell walls containing cellulose and hemicellulose, which give them strength and rigidity. Phloem fibers help in maintaining the structural integrity of the phloem tissue and provide support to the plant.
Tracheids, on the other hand, are a type of xylem cell involved in water transport within plants. Unlike sieve tubes, tracheids do not have perforated end walls but instead have tapered ends with pits that allow for water movement between adjacent cells. Tracheids are responsible for conducting water and dissolved minerals from the roots to other parts of the plant.
In summary, while sieve tubes, companion cells, and phloem fibers are all components of the phloem tissue involved in nutrient transport, tracheids are a type of xylem cell involved in water transport. Therefore, tracheids are the odd one out in the given options.