Question

Lignified cell wall is characteristic feature of
A) Vessels
B) Sieve cells
C) Sieve tubes
D) All of above

Answer 1

Hint:Cell wall is defined as a structural layer which surrounds some type of cell. The cell wall can be flexible, rigid and tough. It provides the support and protection to the cell. The cell wall surrounds the plasma membrane of the plant cell. The cell wall is absent in animal cells.

Complete answer:
->A vessel element is a cell type found in xylem.
->The Vessel elements are found in flowering plants.
->Vessels form an important system for transporting water from root to the leaves and other parts of plants.
->The cell wall of the vessel element is strongly lignified.
->The cell wall of the vessel element is made of lignin.
->Sieve elements are cells that are important for the function of phloem.
->There are two types of sieve elements – sieve tubes and sieve cells.
->Sieve tubes help in transport in phloem. The sieve tube is formed from elongated cells which are interconnected by perforations in their walls.

Hence the correct answer is option ‘A’ vessels .

Note: The side walls of vessel elements have pits. The main difference between sieve cells and sieve tube members is the absence of sieve plates in sieve cells. Vessel elements are the main distinguishing feature between hardwood of angiosperms and softwood of conifers. The vessel elements are absent from most gymnosperms such as conifers. Lignin is a class of organic polymers that is a structural material in the support tissues of vascular plants.