SPECIALISED CELLS

Phloem fibres and sclereids

Distribution : in the primary phloem but are more
common in the secondary phloem of dicotyledons.
to support other phloem cells when the plant is
growing.

Phloem parenchyma
only found in dicotyledonous plants.
act as packaging tissue in the primary phloem.
In secondary phloem, the cells form radial medullary
rays.

Functions of phloem

Translocation of soluble organic products of
photosynthesis.
Sugars and amino acids for example, are translocated
from the leaves ("source") to other parts ("sinks") of
the plant such as the meristem and roots where they
are utilised or stored.
The companion cells are closely associated with the
sieve elements.
They actively move substances such as sugars and
amino acids into the sieve elements.











DISTRIBUTION OF PLANT TISSUES