Question

The major driving force for transport of water through xylem during the day is _________ and during the night, it is ________.

a) root pressure, transpiration
b) transpiration, root pressure
c) diffusion, osmosis
d) active transport, transpiration

Answer 1

Correct answer is (b)

The major driving force for the transport of water through xylem in plants during day is transpiration. It creates a suctional force called the transpiration pull which pulls the water all the way up even in tall trees. During the night, root pressure is reponsible for transportation of water. Transpiration cannot happen during the night due to the lack of sunlight.