Question

Xylem translocates.
A. Water only
B. Water and mineral salts only
C. Water, mineral salts and some organic nitrogen only
D. Water, mineral salts, some organic nitrogen and hormones

Answer 1

Hint:- Xylem and phloem are called as the vascular tissues of the plant as the conducting region of the plant is made up of these tissues. They are a type of complex permanent tissues as they consist of many types of cells.

Complete Answer:-Xylem is the chief conducting tissue of vascular plants responsible for the conduction of water and dissolved mineral salts, some organic nitrogen and hormones.
There are four components of a xylem tissue:
Tracheids- It is the main conducting element in pteridophytes and gymnosperms. It consists of an elongated cell with tapering ends. The cells of this element are devoid of protoplasm and hence dead. The walls constituting the tracheids are hard, thick and lignified. The secondary walls are deposited in the form of thickening of lignin on the inner surface of the original cell wall.
Vessels- These are made up of rows of cells, placed one above the other with their intervening walls absent due to dissolution. Vessels at maturity like tracheids lack the protoplasm. Their cell cavity or lumen is wide. These are mainly found in the angiosperms.
Xylem fibres- These are sclerenchymatous cells associated with the xylem tissue. These are abundant in secondary xylem where they provide mechanical strength.
Xylem parenchyma- These are the living parenchymatous cells associated with xylem. The walls of xylem parenchyma cells are thin and made up of cellulose. The main function of these cells is storage of food but they help in lateral conduction of water and minerals.

So the correct answer is D. Water, mineral salts, some organic nitrogen and hormones.

Note:- The other conducting tissue of the plants i.e. phloem is responsible for translocation of organic solutes. It consists of four elements- sieve elements, companion cells, phloem parenchyma and phloem fibres.