Q. Which of the following statements is/are not true? I.In CAM plants, stomata open during dark and remain closed during the day. II.Role of $Na^{+}$ in stomatal opening is now universally accepted. III.The water potential of root cells is higher than the water potential of soil. IV.Capillarity theory is the most accepted theory of water movement through plants. V.The walls of xylem vessels made up of lingo-cellulose have strong affinity for water molecules.
A) II, III and V
B) II, III and IV
C) I, II and III
D) II and III
Explanation
Sodium, which is essential for animals is not required by most of the plants. Water potential is the difference between the free energy of water in a system and free energy of pure water at atmospheric pressure. The water potential of root cells is lower than the water potential of soil. Cohesion-tension or transpiration pull theory is the most accepted theory of water movement in plants.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.