Transpiration and root pressure cause water to rise in plants by:
pushing it upward
pushing and pulling it, respectively
pulling it upward
pulling and pushing it, respectively
As discussed in
Cohesion tension or transpirational pull theory -
There is a continuous column of water from root through the stem and into leaves. Water molecules are attached with each other by cohesion force, and by walls of tracheary by adhesion force.
- wherein
Given by Dixon and Jolly (1894).
As discussed in
Root pressure theory -
Due to movement of water from soil into the root hair and from there to xylem cells, a hydrostatic root pressure develops which pushes the water up in the xylem vessels.
- wherein
Given by Priestly (1916), the magnitude of pressure is too small for tall trees, hence present in only herbaceous plants.
Transcriptional pull theory and Root pressure theory.
Option 1)
pushing it upward
This solution is incorrect.
Option 2)
pushing and pulling it, respectively
This solution is incorrect.
Option 3)
pulling it upward
This solution is incorrect.
Option 4)
pulling and pushing it, respectively
This solution is correct.