Question

Bidirectional translocation of solutes takes place in

(a) parenchyma

(b) cambium

(c) xylem

(d) phloem.

Answer 1

Answer is (d) phloem.

Explaination:

The high concentration of organic solutes such as sugar inside the cells of the phloem at a source, creates a diffusion gradient which draws water into the cells from the adjacent xylem.

This creates turgor pressure also called as hydrostatic pressure in the phloem.

Movement of phloem sap occurs by bulk flow from the sugar sources to sugar sinks.

Thus, the movement in phloem is bidirectional whereas it is unidirectional in xylem.

The phloem has the cells which have end walls with perforations. So, it has a two way flow.

It translocates water and food materials.

The xylem vessel has the cells with no end walls between the cells so it has one way flow only.

It translocates water and minerals ony.