[Campbell Biology P.833] A plant is exposed to extremely dry conditions, causing its stomata... | Practice Question

A plant is exposed to extremely dry conditions, causing its stomata to close. What is the most likely immediate consequence for water transport within the plant?

  • A: The rate of water absorption by root hairs will significantly increase to compensate for dryness.
  • B: The negative pressure (tension) in the xylem will decrease, leading to a reduced rate of water and mineral transport to the shoots.
  • C: Sugars will be preferentially transported to the roots to encourage new growth.
  • D: Positive pressure will build up in the xylem, leading to guttation.

Explanation

Transpiration, the evaporation of water from leaves through stomata, generates the negative pressure tension that pulls water up the xylem. When stomata close, transpiration is reduced, thereby decreasing the tension and the rate of water transport to the shoots, consistent with Concept 36.3 and 36.4.