Question

Water potential in leaf tissue is 'positive' (near zero) during

• A. Low transpiration
• B. Excessive absorption
• C. Excessive transpiration
• D. Guttation

Answer 1

Answer: (D)

Guttation

Transpiration is the process of evaporation of water from the upper surface of the leaves.

(A)Low transpiration indicates the low level of water evaporated and the water potential is negative.

(B)Excessive absorption indicates the entering of the molecule to bulk phase and the water potential is negative.

(C)Excessive transpiration indicates the high level of water evaporated and the water potential is negative.

(D)Guttation occurs due to root pressure. It is the loss of water through leaves in the absence of photosynthesis. Due to root pressure water moves upwards and at this point, the amount of water is more in leaves than the atmosphere so water potential is positive.

So, the correct answer is 'Guttation'.