What anatomical adaptation enables hydrophytic plants like water lettuce (Pistia) and water hyacinth to float buoyantly on water surfaces?
Answer and explanation
Correct answer: C. spongy aerenchyma tissue containing extensive air spaces within petioles and leaves
- Step 1: Hydrophytes require buoyancy to keep photosynthetic leaves at the water surface. Step 2. They possess aerenchyma (spongy parenchyma with large intercellular air chambers), which provides both buoyancy and internal gas transport. Answer: spongy aerenchyma tissue containing extensive air spaces within petioles and leaves. Why not the others: Lignified wood would sink the plant; submerged parts lack thick cuticles; free-floating hydrophytes lack benthic taproots.
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