Question

Which two forces cause water and minerals to move up the xylem?

Answer 1

Cohesion-tension-transpiration pull and root pressure.

1. The two forces that are involved in the ascent of xylem sap are cohesion-tension-transpiration pull and root pressure.
2. Cohesion-tension-transpiration pull model was originally proposed by Dixon and Jolly in 1894 and further improved by Dixon in 1914.
3. According to this theory, due to transpiration, the water column inside the plant is pulled up and that leads to ascent of sap.
4. Root pressure is the transverse osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves.
5. In simple words, when root pressure occurs solution/water does not need to enter again (twice) that can be prevented by osmotic pressure.