ICSE Class 8 Answered

Components of Phloem

Component

Characteristics

Location

Function

Sieve tubes

• Tubular cells with perforated walls and arranged end to end.
• As they mature, they lose the nuclei and most of the other organelles in the cytoplasm. The remaining cell organelles stick to the inside of the cell wall.
• The rest of the cytoplasm moves from cell to cell to carry substances.
• Structural component of the phloem.

• Translocation of organic substances through perforated walls from one adjacent cell to another.

Companion cells

• They surround sieve tube elements.
• Cells are living and keep their nuclei and other organelles throughout their life.
• Structural component of the phloem.

• Help to control the activity of sieve tube elements.

Phloem fibres

• Elongated tapering dead cells.
• Cell walls are thickened.
• Found particularly in the stem.

• Provide mechanical strength to the plant.

Phloem parenchyma

• Cells are alive and filled with cytoplasm.
• Cell walls are thin.
• Cells form the packing tissue between all the other types of cells.
• Structural component of the phloem.

• Stores compounds such as starch.
• Transports food, i.e. sugars and amino acids from leaves to other non-green parts of plants such as growing stems and roots.