Question

The elements of xylem tissue that store tannins are
A. Tracheids
B. Vessels
C. Xylem parenchyma
D. Xylem fibers

Answer 1

Hint:
The element that stores tannins are the only component in the xylem that is made of living cells. This element assists in the transportation of water over short distances. The cells have prominent nuclei and large vacuoles.

Complete answer:
The elements of xylem tissue that store tannins are xylem parenchyma.
Xylem parenchyma is the only component of the xylem that is made of living cells. The cells have abundant cytoplasm and prominent nuclei. One of the main functions of xylem parenchyma is to store starch, fats, crystals, and tannins. The cells of xylem parenchyma are also involved in the maintenance of the xylem transport capacity.

Additional information:
Now, let us discuss the other elements of xylem:
Tracheids:
They are tube-like non-living cells with tapering ends. They are predominantly found in gymnosperms and lower angiosperms. The cell wall is highly lignified. The main function of tracheids is the transportation of water and minerals.
Vessels:
Vessels are tube-like structures with a cylindrical appearance. They are composed of non-living tube-like cells. The cell walls are lignified and even have a central cavity. The cells are connected with the help of perforations present in common walls. Vessels help in the conduction of water and minerals and also provide mechanical strength to the plant.
Xylem fibers:
Xylem fibers are similar to tracheids and vessels. They are made up of non-living cells and have lignified walls. They are involved in the transportation of water and providing mechanical support to the plant.

Note: Tannins are metabolites that are produced by plants. They are derived from phenolic acid and they protect the plant against insect herbivores. Tannins even protect the bark of trees from fungi and bacteria infections.