Which property of water enables it to move from the roots to the leaves of a plant?

Question

Which property of water enables it to move from the roots to the leaves of a plant??  
A. Heat capacity  
B. Conductivity  
C. Solution  
D. Cohesion

Accepted Answer

Correct Answer: (D)Cohesion. 
Rationale: The cohesive property of water is primarily responsible for its ability to move from roots to leaves in tall plants.The movement of water and dissolved minerals upward through the xylem vessels of a plant is explained by the cohesion-tension theory. Cohesion refers to the attraction between water molecules due to hydrogen bonding. This attraction allows water to form a continuous column within the narrow xylem tubes. As water evaporates from the leaves through stomata (transpiration), it creates a negative pressure or tension. This tension pulls the cohesive water column upward from the roots, much like sucking on a straw. Adhesion, the attraction between water molecules and the walls of the xylem vessels, also helps support the column against gravity. The combined forces of cohesion and adhesion, driven by transpiration, enable water transport to great heights.A) Heat capacityWater's high specific heat capacity allows it to absorb and release large amounts of heat with minimal temperature change. This property is crucial for temperature regulation in organisms and ecosystems, but it does not directly contribute to the upward movement of water in plants.B) ConductivityConductivity generally refers to the ability to conduct heat or electricity. Water is a good conductor of heat and, when ions are dissolved, electricity. However, this property is not the mechanism for bulk water flow in xylem. The xylem conducts water via mass flow, not via thermal or electrical conduction.C) SolutionWater's excellence as a solvent creates the xylem sap, a solution of minerals and ions. This property is important for nutrient transport, but the physical movement of the solution itself is driven by the cohesion-tension mechanism, not simply its solubility.D) CohesionCohesion is the key property that allows water to be pulled up as a continuous column under tension. Without the strong hydrogen bonds between water molecules, the column would break under the stress of evaporation and gravity, and water transport would be limited to very short distances.ConclusionWhile water's solvent properties and heat capacity are vital for life, the specific challenge of lifting water against gravity in tall plants is solved by its cohesive nature. Cohesion, coupled with adhesion and the driving force of transpiration, forms the basis of the cohesion-tension theory, which explains the ascent of sap.

Which property of water enables it to move from the roots to the leaves of a plant?

A
Heat capacity

B
Conductivity

C
Solution

D
Cohesion

The cohesive property of water is primarily responsible for its ability to move from roots to leaves in tall plants.

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Related Questions

Which property of water enables it to move from the roots to the leaves of a plant?

A Heat capacity B Conductivity C Solution D Cohesion

The cohesive property of water is primarily responsible for its ability to move from roots to leaves in tall plants.

Topic Flashcards

Mini Quiz

Related Questions

A
Heat capacity

B
Conductivity

C
Solution

D
Cohesion