Question

Sieve cells and sieve tubes are known as sieve elements.

• A. True
• B. False

Answer 1

The correct option is A True

Both sieve cells and sieve tubes are sieve elements. But Sieve cells, which occur in pteridophytes and gymnosperms, are single cells with less specialized sieve areas usually in their lateral walls, whereas sieve tubes, which occur in angiosperms, are longitudinal file of cells with highly specialized sieve area (sieve plate) usually in or near an end wall. The most characteristic feature of sieve tubes is the presence of thickened cross walls between two adjacent sieve tube members, which are known as sieve plates.