Explain the mechanisms by which water moves from roots to leaves?

Question

Explain the mechanisms by which water moves from roots to leaves?

Answer 1

water potential = pressure p., solute p., matric p.  hypothesis #1 water moves up xylary elements via capillarity.  #2 water is pushed up xylary elements by atmospheric pressure.  #3 water is pumped up the xylary elements. #4 water is pushed up by root pressure.  #5 water is pulled up by evaporation.   the transpiration-cohesion hypothesis (#5) best explains how water moves in xylem.  the driving force for the movement of water is a water-potential gradient generated by transpiration.  transpiration from the leaves lifts water up plants.  cohesion of water molecules prevents the columns of water from breaking, and adhesion of water molecules to cell walls prevents gravity from draining the water column

Answer 2

There is a higher concentration of soluble substances inside the cells of the roots.  As a result, water will flow into the roots from the soil particles when root hairs make contact with the particles.  Water can flow through the cell walls, across the plasma membrane of the cells until it reaches the tissue called the endodermis.  The endodermis has a water proof region called the Casparian strip that forces all the water through the cytoplasm of the cell.  From there, transpiration through the leaves of the plant creates a negative pressure in the xylem cells of the root pulling water to the top of the plant.

Answer 3

simpler way is.....capillary action and transpiration both occuring at opposite ends to favour each other!! d 1st one at roots n d 2nd on leaves!!