Stomatal Apparatus and Stomata Structure — NEET Biology
📚 Practice ConceptWhat is stomatal apparatus? Explain the structure of stomata with a labelled diagram.
Which of the following statements regarding the stomatal apparatus and associated epidermal structures are NOT correct? S1: Stomata, crucial for transpiration and gaseous exchange, are exclusively found on the adaxial epidermis of dorsiventral leaves. S2: The inner walls of guard cells, which are towards the stomatal pore, are characteristically thinner and more elastic than their outer walls. S3: Subsidiary cells are specialized epidermal cells that are always present around guard cells, forming an indispensable part of the stomatal apparatus. S4: Guard cells, uniquely among epidermal cells, possess chloroplasts enabling them to regulate stomatal movement through turgor changes driven by photosynthesis. S5: In grasses (monocotyledons), the guard cells are distinctly dumb-bell shaped, whereas in most dicots they are bean-shaped. S6: The complete stomatal apparatus comprises the stomatal aperture, the guard cells, and any surrounding subsidiary cells, if present.
View solution & NCERT explanation
Correct answer: A — S1, S2 and S3 only
Let's evaluate each statement to identify the incorrect ones: S1: This statement is NOT correct. While stomata are present on leaves, dorsiventral (dicot) leaves generally bear more stomata on the abaxial (lower) epidermis than the adaxial (upper) epidermis. Also, monocot (isobilateral) leaves have stomata on both surfaces. Thus, they are not exclusively found on the adaxial epidermis. (NCERT Page 76, Section 6.2.5; Page 77, Section 6.2.6) S2: This statement is NOT correct. The outer walls of guard cells (away from the stomatal pore) are thin, while the inner walls (towards the stomatal pore) are highly thickened. (NCERT Page 72, Section 6.1.1) S3: This statement is NOT correct. Subsidiary cells are specialised epidermal cells that are found *sometimes* in the vicinity of guard cells. They are not *always* present, nor are they an indispensable part of the apparatus in all cases, though they are part of the stomatal apparatus *when present*. (NCERT Page 72, Section 6.1.1) S4: This statement is correct. Guard cells are unique among epidermal cells in containing chloroplasts, allowing them to perform photosynthesis and regulate stomatal opening and closing via turgor changes. (NCERT Page 72, Section 6.1.1) S5: This statement is correct. Guard cells are indeed dumb-bell shaped in grasses and bean-shaped in most dicots (general shape). (NCERT Page 72, Section 6.1.1) S6: This statement is correct. The stomatal aperture, guard cells, and surrounding subsidiary cells (if present) together constitute the stomatal apparatus. (NCERT Page 72, Section 6.1.1) Therefore, statements S1, S2, and S3 are NOT correct.
What does NCERT say about What stomatal apparatus Explain?
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.