Which xerophytic adaptation is characterized by a green, flattened, succulent stem that carries out photosynthesis while leaves are reduced to spines?
Answer and explanation
Correct answer: B. Phylloclade in Opuntia
- Step 1: In extreme arid conditions, plants minimize transpirational surface area by reducing leaves to spines.
- Step 2: The stem takes over the photosynthetic role by becoming green, succulent, and flattened with unlimited growth (phylloclade), as seen in Opuntia.
- Step 3: (In Euphorbia, the phylloclade is fleshy and cylindrical).
Answer
Phylloclade in Opuntia
Why not the others: 'Cladode in Asparagus' is a green photosynthetic branch of limited growth (usually one or two internodes); 'Phyllode in Australian Acacia' is a modified, flattened photosynthetic petiole, not a modified stem; 'Stolon in Fragaria' is a sub-aerial runner for vegetative propagation.
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