Question

Which of the following factors affect the absorption of water by roots?

• A. Soil temperature
• B. Soil aeration
• C. Relative humidity of the atmosphere
• D. All of the above

Answer 1

Answer: (D)

All of the above

• Water is lost from plants due to transpiration from aerial parts. This creates a transpiration pull in the vascular system which is ultimately responsible for passive absorption of water from the soil.
• Transpiration loss of water depends on vapour pressure gradient between leaf mesophyll tissue and atmosphere. Thus, atmospheric humidity is an important factor that determines absorption of water from soil.
• Water can also be absorbed actively from soil. Active absorption depends on cellular respiration which produces ATP. Hence, soil aeration and temperature are also important factors which can affect water absorption from soil.
• Both high temperature and low aeration will discourage cellular respiration in roots.