Question

Guttation is the release of liquid water from veins at the leaf margins. It is caused by

• A. Transpiration
• B. High leaf pressure
• C. High root pressure
• D. Clogged tracheids or vessel elements.

Answer 1

Answer: (C)

High root pressure

Guttation is the process of loss of impure water (a dilute solution of different organic and inorganic substances) from plant infact, mostly from margins of leaves. It occurs when transpiration rate is very low as compared to rate of water absorption. Due to this root pressure is developed and water is pushed out through specialised pores at vein endings called hydrathodes. Each hydrathode is made up of group of loosely arranged achlorophyllous or colourless and parenchymatous cells called epithem. These cells help in absorbing a good percentage of inorganic and organic solutes present in the exudate. Thus guttation is due to the positive pressure in the xylem developed due to the root pressure.

So, the correct answer is option C.