The relay pump theory was given by

Solution (By Examveda Team)

The relay pump theory was given by Godlewski.
Godlewski (1884) proposed his clambering or relay-pump theory to explain the vertical movement of water through the plant.
He thought that a rhythmic change in the water potential of the living cells like the xylem parenchyma and medullary rays caused a pumping action to raise water vertically against gravity.