Q11
The water potential of pure water is
Correct Answer
Option D
Solution
(d) By convention, water potential of pure water at standard conditions = 0.
Transport in Plants
Q12
The principal pathway of water translocation in angiosperms is
Correct Answer
Option C
Solution
(c) Water moves primarily through xylem vessel system (tracheary elements).
Q13
Which of the following is used to determine the rate of transpiration in plants?
Correct Answer
Option B
Solution
(b) Potometer measures rate of water uptake as a proxy for transpiration rate.
Q14
An adaptation for better gaseous exchange in plant leaves is
Correct Answer
Option D
Solution
(d) Stomata on lower surface exchange gases efficiently while reducing water loss.
Q15
Which is produced during water stress that brings stomatal closure?
Correct Answer
Option B
Solution
(b) ABA (abscisic acid) = stress hormone; causes K+ efflux from guard cells → stomata close.
Q16
Plants die from prolonged water-logging because
Correct Answer
Option B
Solution
(b) Water-logging deprives roots of oxygen, stopping aerobic respiration → root death.
Q17
Which of the following plant is found to have minimum transpiration?
Correct Answer
Option A
Solution
(a) Nerium is xerophytic with sunken stomata, minimizing transpiration.
Q18
Stomata open and close due to
Correct Answer
Option D
Solution
(d) Turgor pressure changes in guard cells control stomatal opening and closing.
Q19
Stomata of a plant open due to
Correct Answer
Option B
Solution
(b) K+ influx into guard cells increases osmotic pressure → water entry → turgidity → stomata open.
Q20
Potometer works on the principle of
Correct Answer
Option B
Solution
(b) Potometer: water absorbed ≈ water transpired — measures rate of water uptake.
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