Class 11 NEET Biology Anatomy of Flowering Plants Questions Part 1

(c) : In pteridophytes and gymnosperms, sieve tubes are not arranged in linear rows and hence called sieve cells. Sieve tube elements are the conducting element of phloem. These are arranged end to end in linear rows with septa (sieve plate) between two sieve tube elements. In the sieve plate, there are present sieve pores. Sieve tube elements are living and have thin cellulosic walls in young cells but they become thick walled and are without nuclei at maturity.