noun, plural: phloems
A vascular tissue in plants that functions primarily in transporting organic food materials (e.g. sucrose) from the photosynthetic organ (leaf) to all the parts of the plant
In plants, the different types of tissues include the meristematic tissues, the permanent tissues, and the reproductive tissues. The permanent tissues are further classified into fundamental tissues and the complex permanent tissues. The complex permanent tissues include the vascular tissues, particularly, xylem and phloem.
The phloem is a vascular tissue responsible for the translocation, i.e. a process in plants responsible for transporting the photosynthate materials to all parts of a vascular plant. It is comprised of the following major components:
(1) sieve elements
(2) companion cells
(3) phloem sclerenchyma
(4) phloem parenchyma
The phloem may be classified into the following based on the stage or origin of growth:
In woody plants, particularly trees, the phloem is the innermost layer of the bark, next to the wood. It usually contains a large proportion of woody, fibrous cells, and is, therefore, the part from which the fibre of the plant is obtained, as that of hemp, etc.
Word origin: Greek phloos (bark)