Explanation

Due to continuous transpiration from the leaves surface, mesophyll cells of leaves withdraw water from deeper cells as its molecules are binded by hydrogen bond. Deeper cells obtain water from tracheary elements, which in turn cause a tension in water column of tracheary elements. As this tension is created by transpiration, it is referred to as transpirational pull. On account of this tension, the water column of plant is pulled up passively below the top most part of plant. A transpiration pull of 10-20 atm is sufficient to left the water up to the height of tallest plant over 130 metre