Question

All the following statements regarding sieve tube elements are true except

• A. Their end walls have perforated sieve plates, which become impregnated with lignin at maturity.
• B. They possess a peripheral cytoplasm as well as large vacuole.
• C. Distinct proteinaceous inclusions, the P-proteins are seen evenly distributed throughout the lumen.
• D. Long, slender, tube-like structures arranged in longitudinal series.
• E. They are devoid of nucleus at maturity.

Answer 1

Answer: (A)

Their end walls have perforated sieve plates, which become impregnated with lignin at maturity.

Sieve tube elements are one of the components of phloem and are involved in food transport from leaves to other plant tissues. These are long, slender, tube-like structures arranged in longitudinal series with perforated seive plates. They are interconnected by sieve plates. These are living cells which lose nucleus at maturity and are not lignified at maturity.
Thus, the correct answer is option A.