Opening and closing of stomata are due to the:

1. Hormonal change in guard cells

2. Change in Turgor pressure of guard cells

3. Gaseous exchange

4. Respiration

Mark the statements true (T) or false (F).

A. Less than 1 percent of water reaching the leaves is used in photosynthesis and plant growth.

B. Cellulose microfibrils of guard cells are oriented longitudinally, making it easier for the stoma to open.

C. Transpiration can create pressure sufficient to lift a xylem sized column of water over 130 metres high.

D. C₄ plants lose only half as much water as a C₃ plant for the same amount of CO₂  fixed.

     A      B      C       D

1.  F      T       F       T

2.  F      T       F       F

3.  T      F      T        T 

4.  T      F      F        T

Which of the following facilitates opening of stomatal aperture?

The inner wall of guard cell is not