The most widely accepted explanation for the ascent of sap in trees is
Correct answer: D. Transpiration cohesion theory of Dixon
- A. Capillarity
- B. Role of atmospheric pressure
- C. Pulsating action of living cells
- D. Transpiration cohesion theory of Dixon
Explanation
The transpiration cohesion theory states that water molecules in the xylem of a tree are held together by cohesion, or the attraction between water molecules. The water molecules are also attracted to the walls of the xylem vessels, creating tension. The tension in the water column is what pulls the water up the tree.
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About Forms and Functions of Plants
Plant nutrition and transport cover mineral uptake, photosynthesis, xylem movement of water and minerals, and phloem translocation of sugars. Plant growth regulators include auxins, gibberellins, cytokinins, abscisic acid and ethene, whose effects on cell division, elongation, dormancy, fruit ripening and tropic responses should not be confused with mineral nutrition.
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