Question

An additional apoplastic route that allows direct access to xylem is along the secondary roots because they ______.

• A. do not pass through endodermis
• B. have plasmodesmata
• C. develop from pericycle
• D. are made up of non-living cells

Hint:

Secondary roots arise from the pericycle, which lies just inside the endodermis.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept
Casparian strips in the endodermis normally block the apoplastic movement of water into the stele.

Step 2: Origin of secondary roots
Secondary (lateral) roots arise from the pericycle, the layer just inside the endodermis.

Step 3: Effect
As a young lateral root grows outward, it pushes through the endodermis and cortex. The endodermal barrier is broken at the point of emergence, so water in the cell walls can reach the xylem directly.

Final Answer:
The extra route exists because secondary roots develop from the pericycle. \[ \boxed{\text{(C) }\text{develop from pericycle}} \]