Question

Which of the following is true/false regarding transport of substances in plants?
(i) Mass flow is the movement of substance in bulk as a result of pressure difference.
(ii) Bulk flow is achieved only through a positive hydrostatic pressure gradient.
(iii) The apoplast system is the system of interconnected protoplasts.
(iv) Most of the water flow in the roots occurs via the apoplast since the cortical cells are loosely packed, and offer no resistance to water movement.

• A. (i) and (iv) are true; (ii) and (iii) are false.
• B. (i) and (ii) are true; (iii) and (iv) are false.
• C. (ii) and (iii) are true; (i) and (iv) are false.
• D. (i), (ii) and (iv) are true; (iii) is false.

Answer 1

The correct option is D (i), (ii) and (iv) are true; (iii) is false.

(i) The movement of a substance in bulk as a result of pressure difference is called mass flow.

(ii) A positive hydrostatic pressure gradient usually results in mass flow.

(iii) The system of interconnected protoplasts is known as a symplastic system.

(iv) Most of the water flows in the via the apoplasts since the cortical cells are loosely packed, and offer no resistance to water movement.

So, the correct answer is '(i), (ii) and (iv) are true; (iii) is false.'