Characteristics and functions of vascular tissues in plants

– vascular tissues consist of xylem and phloem
xylem is mainly made up of dead cells, vessels and tracheids
– highly lignified
– hollow and possess no cytoplasm
– perforated at both end and generally tapered
– cylindrical in shape
– normally joined end to end forming tube/pipe
– structure is highly suited for maintaining a continuous column of water molecules
– facilitates movement of water and mineral nutrients from column to leaves.
phloem is mainly made up of sieve tubes (elements)
– cells contain cytoplasm and cytoplasmic strands
– companion cells are also present
– these retain their nuclei
– end plates are perforated
– may or may not possess pits which may be open or have regulatory covers/appendages/torus
– cytoplasmic strands aid cell to cell communication through end plates
– companion cells provide metabolic energy needed for active transport of materials
– pits assist in transverse movement of materials
– whole system facilitates translocation of organic materials from sources of sinks.

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