The most widely accepted theory of ascent of sap is
Options
(a) capillarity
(b) pulsatory movement of living tissue
(c) role of atmospheric pressure
(d) transpiration pull and cohesion
Correct Answer:
transpiration pull and cohesion
Explanation:
Cohesion and transpiration pull theory was proposed by Dixon and Jolly in 1894. This theory is based on two parts
(i) Transpiration pull exerted on the water column.
(ii) Cohesive property of water molecules forms and unbroken column or water in the xylem. Root pressure theory was put forward by Priestley. Root pressure is a positive pressure that develops in the xylem sap of the root of some plants. It is a manifestation of active water absorption. Vital force theory (pulsation theory) about ascent