Question

Which of the following is NOT the characteristic feature of xerophytic plants?

• A. Lacks Aerenchyma
• B. Chlorophyll mostly in stem and leaves
• C. Palisade generally on both sides of leaves
• D. Thin walled epidermal cells

Hint:

When thinking about xerophytes, always consider adaptations that would help a plant survive a drought. Thick cuticle, sunken stomata, reduced leaves, and deep roots are all features that reduce water loss or increase water uptake. Thin cell walls would do the opposite.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
The question asks to identify a feature that is NOT an adaptation found in xerophytes (plants adapted to survive in arid conditions). Xerophytic adaptations are primarily aimed at reducing water loss and storing water.
Step 2: Detailed Explanation:
Let's analyze the features listed:

(A) Lacks Aerenchyma: Aerenchyma is a spongy tissue with large air spaces found in aquatic plants (hydrophytes) for buoyancy and gas exchange. Xerophytes, living in dry conditions, do not need this tissue. Its absence is characteristic of them.

(B) Chlorophyll mostly in stem and leaves: In many xerophytes, leaves are reduced to spines to minimize water loss (e.g., cactus). In such cases, the stem becomes flattened, green (containing chlorophyll), and takes over the function of photosynthesis. This is a common xerophytic adaptation.

(C) Palisade generally on both sides of leaves: Leaves that are exposed to high light intensity from all angles (isobilateral leaves) often have palisade mesophyll on both the upper and lower sides to maximize photosynthesis. This is a common feature in xerophytes.

(D) Thin walled epidermal cells: This is not a xerophytic feature. To prevent water loss through transpiration, xerophytes have very thick-walled epidermal cells, often covered by a thick waxy cuticle and multiple layers of epidermis. Thin walls would offer little resistance to water loss.

Step 3: Final Answer:
Thin-walled epidermal cells are characteristic of hydrophytes or mesophytes, not xerophytes. Therefore, this is the feature that is not characteristic of xerophytic plants.