NCERT Books for Class 9 Science Chapter 6

Xylem transports water and minerals absorbed by the roots of the plants to different parts of the plant, which does not have a sufficient amount of water and minerals. It consists of four parts, which are - 

• Vessels

• Tracheids

• Xylem fibers

• Xylem parenchyma 

Phloem: Phloem is the tissue that transports plant food created in leaves with the help of photosynthesis to the different parts of the plant. It also consists of four parts.

• Sieve tube

• Companion cells

• Phloem parenchyma

• Phloem fibers

Permanent tissues are formed from the cells which have lost their ability to divide and are formed from meristematic tissues. And simple permanent tissues are permanent tissues which are formed only of 1 type of cell.

The simple permanent tissues are classified in three categories which are - 

• Parenchyma: Parenchyma are loosely packed living cells, which provide support to the structure of the plant and store excess plant food. These types of cells have relatively thin cell walls.

• Collenchyma: It consists of elongated living cells with irregularly thick walls at the corners. The cell walls in them are created of cellulose and pectin. They have relatively small intercellular space.

• Sclerenchyma: These are long, dead cells with thick cell walls. The cell walls have a deposition of lignin in their cells.