Which evidence supports the theory of water movement by root pressure in flowering plants? 1 When the rate of transpiration of a tree is maximum, the diameter of the trunk is minimum. 2 When a plant shoot is removed close to the base of the stem, sap leaks out from the cut. 3 Evaporation of water from a porous pot can exert a force that draws water up a glass tube attached underneath the pot. 4 Droplets of water form at the edge of leaves of plants growing in conditions of soil with high water content and air with high humidity.