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प्रश्न
Explain capillarity theory.
Answer the following question.
Explain capillarity theory of water translocation.
उत्तर
Capillarity theory of water translocation:
- This theory was put forth by Boehm in (1863).
- According to this theory, physical forces and dead cells are responsible for the ascent of sap. For e.g. Wick dipped in an oil lamp, shows capillarity due to which oil is raised upwards. The conduction of water in a straw dipped in water is raised to a certain height because of capillarity. The height to which water is raised depends on the diameter of the straw.
- Capillarity is because of surface tension, and forces of cohesion (attraction between like molecules) and adhesion (attraction between unlike molecules).
- Xylem vessel/ tracheid with its lumen can be compared with straw.
- Water column exists because of combined cohesive and adhesive forces of water and xylem wall, due to capillarity.
- Due to capillarity, water is raised or conducted upwards against gravity, to few centimeters only.
संबंधित प्रश्न
Very short answer question.
In which conditions transpiration pull will be affected?
Answer the following question.
Discuss theories of water translocation.
Answer the following question.
Define and or explain the term:
Ascent of sap
Long answer question.
Explain cohesion theory for translocation of water.
Find the physical process NOT involved in absorption of water in plants.
Oozing of sap from the cut end of herbaceous plants is due to ____________.
Root pressure theory was proposed by ______.
Arrange and rewrite the terms in group in correct order to be in a logical sequence, beginning with the term that is underlined:
Water vapour, Soil water, Leaves, Ascent of Sap.
What are the four main forces which contribute to the ascent of sap (upward movement of water and minerals) ? Name them and explain in short.
How is transpirational pull caused?
