Question
Biology Question on Principles of Inheritance and Variation
Stomatal aperture is surrounded by guard cells and widens (opens) when guard cells are _____________.
A
(A) flaccid
B
(B) turgid
C
(C) bean shaped
D
(D) dumb-bell shaped
Answer
(B) turgid
Explanation
Solution
Explanation:
Stomatal aperture is surrounded by guard cells and widens (opens) when guard cells are turgid. The kidney-shaped cells surrounding each stoma are guard cells. They regulate the rate of transpiration by opening and closing the stomata. When the guard cells are turgid, or swollen, the stomatal opening is widened. This turgidity is due to accumulation of K+ ions. Potassium ions move into the vacuoles. The water moves into the vacuoles, following potassium ions. As a result, the guard cells expand and the stoma opens.Hence the correct option is (B).