Question

The transport system in plants consists of two kinds of tissues X and Y. The tissue X is made up of living cells and consists of two components A and B. The component A has tiny pores in its end walls and contains only cytoplasm but no nucleus. On the other hand, component B has cytoplasm as well as nucleus. The tissue Y is made up of dead cells and consists of two components C and D. The component C has open ends whereas component D does not have open ends. In flowering plants, either only C or both C and D transport water but D is the only water conducting tissue in non-flowering plants.
(a) What is (i) tissue X (ii) component A, and (iii) component B?

Answer 1

(i) Tissue X is phloem.

• Phloem is a vascular tissue in plants responsible for the transport of food and other materials (plant hormones) to different parts of the plants.

(ii) Component A is the sieve tube
(iii) Component B is the companion cell.

• Both sieve tube and companion cells are living and joined together side by side.
• The Sieve tube has tiny pores in its end walls and contains only cytoplasm but no nucleus. On the other hand, companion cell has cytoplasm as well as nucleus.