Question

Select the correct match.

Apparatus	Function
A. Ganong potometer	(i) Rate of growth
B. Cobalt chloride paper	(ii) Rate of transpiration
C. Pfeffer's auxanometer	(iii) Differential transpiration
D. Porometer	(iv) Opening and closing of stomata

• A. A- (ii), B- (iii), C- (i), D- (iv)
• B. A- (i), B- (ii), C- (iii), D- (iv)
• C. A- (iv), B- (i), C- (iii), D- (ii)
• D. A- (iii), B- (i), C- (iv), D- (ii)

Answer 1

The correct option is A A- (ii), B- (iii), C- (i), D- (iv)

Potometer is an instrument for measuring rate of transpiration by shoots through measuring the rate of their water absorption, as the two are nearly equal, e.g., Ganong's potometer.
Dry cobalt chloride is blue, while the moist one is pink. Change in colour of cobalt chloride filter paper from blue to pink indicates transpiration. There will be more transpiration from lower surface as their are more number of stomata on the lower surface.
Auxanometer is used to measure growth in terms of elongation of plant axis.
Porometer was developed by F. Darwin in 1912. It is an instrument that gives a rough idea about the degree of stomatal opening.