Transpiration is measured by
a)	Photometer	b)	Porometer	c)	Auxanmeter	d)	Respirometer

(a)

The rate of transpiration can be measured by Farmer’s protometer or Ganong’s photometer. These are based on the assumption that the rate of transpiration is nearly equal to the rate of absorption of water. The opening and closing of stomata are measured by porometer.