Question

Assertion :Long distance flow of photoassimilates in plants occurs through sieve tubes. Reason: Mature sieve tubes have parietal cytoplasm and perforated sieve plates.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
• C. Assertion is correct but Reason is incorrect.
• D. Assertion is incorrect but Reason is correct.

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Sieve tubes are living cells, which are specialized for long distance transport of sugars. The mature sieve tubes have parietal cytoplasm and have clusters of pores in the cell walls, known as sieve areas, which have either small pores or large pores; the latter are known as sieve plates. Sieve plates are mostly located on the overlapping adjacent end walls. Thus, the correct answer is option A.