Question

Explain capillarity theory given by Boehm for ascent of sap.

Answer 1

Boehm gave the theory of capillary force in 1809. It states the following:
Xylem vessels are arranged one above the another and forms a sort of continuous channels. Their arrangement resembles that of the capillary tube. So, it was thought that just like in capillary tube, the water rises due to capillary force, ascent of sap also takes place in the xylem of the plants which are arranged in the same manner as capillary tube.