Question

Which of the following pressures is sufficient to lift the water up in small plants.

Answer 1

Root pressure or it is sometime called + pressure or pushing force it is Maxx when there is less transpiration

Answer 2

The answer is root pressure.  

Root pressure is the osmatic pressure within the plant cells of a root which results in pushing the sap upwards through the plant stem to the leaves. Root pressure arises in the xylem of vascular plants.

When moisture level in soil remains high either at night or when transpiration remains low during daytime, root pressure gets optimum.