Question

The continuity of water column in xylem is maintained due to

• A. Presence of air bubbles
• B. Cohesive property of water
• C. Evaporation power of water
• D. None of the above

Answer 1

The correct option is B Cohesive property of water

According to the most widely accepted theory of Dixon and Jolly for ascent of sap; the ascent of sap in plants is a passive physical process, which occurs under the influence of transpiration pull generated due to loss of water from aerial parts. Other than the pull, a continuous column of water is also essential for rise of water in xylem elements. The continuous column of water is maintained by cohesion forces between water molecules and adhesive forces between water molecules and vascular elements of the plant.