Question

An additional apoplastic route that allows direct access to xylem in plants is along the secondary roots because they __________

• A. have no casparian strips
• B. have plasmodesmata
• C. develop from the pericycle
• D. are non-living cells

Hint:

Secondary roots break through the endodermis, so a barrier is missing at those points.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept
In roots, the apoplast pathway is blocked at the endodermis by Casparian strips.

Step 2: Secondary roots
Secondary roots arise from the pericycle and push through the endodermis.
At these points no Casparian strips are present, so water can move in the apoplast directly to the xylem.

Step 3: Conclusion
The reason is that they have no Casparian strips.

Final Answer:
Secondary roots lack Casparian strips, giving direct apoplastic access to xylem. \[ \boxed{\text{(A) }\text{have no casparian strips}} \]