Question

a potometer was used to measure the rate of uptake of water by a leafly shoot under shoot under four different condition ; A) leave in still air with no petroleum jelly applied to them. B) leave is moving air with no petroleum jelly applied to them. C) leaves in still air with the lower leaf surface covered in petroleum jelly. D) leaves is moving air with lower leaf surface leaf surface covered in petroleum jelly.
1)rank the expected rated to uptake of water for condition A to D, from highest to lowest.
2) explain your answer.

Answer 1

1] B,A,D,C

2] Leaf b has no petroleum jelly on its lower surface and is in moving wind which increases rate of transpiration hence it has highest rate of water intake. Leaf A's stomata is not covered but it is in still wind. Hence it ranks lower than B. D has petroleum jelly on it but is in moving air hence it ranks higher than C as C is in still air and has petroleum jelly covering its stomata. Hence C has the least rate of uptake of water due to least transpiration and ranks lower than d and has the lowest ranking.

Note: rate of intake of water depends mainly on transpiration rate.