Anatomy Of Flowering Plants

The phloem consists of sieve elements, companion cells, phloem fibres and phloem parenchyma. Sieve tube members are long, slender, tube-like cells joined end to end to form long tubular channels, the sieve tubes.

The cells of sclerenchyma are long or short, narrow, thick walled and lignified. These are dead cells and do not perform any metabolic function. Tracheids (tracheary element) are elongated cells with tapering ends. The wall of tracheids is moderady thick and usually lignified.

It is a zone of low mitotic activity located in the sub-apical region of root.

Sclerenchyma consists of long, narrow cells with thick and lignified cell walls having a few or numerous pits. They are usually dead and without protoplasts. Sclerenchyma is the chief mechanical tissue which provides mechanical support to mature plant organs.

Medullary rays or Wood rays are made up of xylem parenchyma.