Question

(a) Draw a labelled diagram of (i) a xylem vessel, and (ii) a sieve tube (or phloem).
(b) What are the differences between the transport of materials in xylem and phloem?

Answer 1

(a) Structure of a xylem vessel



Structure of sieve tube (or phloem)


(b) Difference between transport of materials in xylem and phloem:

Transport of materials in xylem	Transport of materials in phloem
Xylem involves the transport of water and minerals from the soil via roots to the rest of the plant body.	Phloem involves transport of food materials from the leaves to different parts of the plant body.
Movement of water is unidirectional, i.e. upwards from the roots to the aerial parts of the plant.	Movement of food is bidirectional, i.e. both upward and downward.
Transport of material in xylem requires physical forces such as transpirational pull.	Transport of material in phloem requires energy in the form of ATP.