Question

Transpiration cohesion theory explains that, the upward pull of water is transmitted from top to bottom by cohesion of molecules caused by

• A. Hydrophilic cell walls
• B. Hydrogen bonds
• C. Oxygen bonds
• D. Surface tension

Answer 1

The correct option is B Hydrogen bonds

Transpiration cohesion theory explains that the upward pull of water was proposed by botanist Henry Dixon in 1939. When the plant leaves transpire water, this results in the creation of tension to pull water from roots to leaves. This tension has to be kept maintained because water molecules display an attraction to one another called cohesion. Because of this cohesive force between the water molecules, the water column doesn't break. Hydrogen bonds among water molecules prevent division, so water is pulled upward through the continuous fluid column.

So, the correct answer is option B.