It is this cell turgor that gives the plant support. If however, plant cells are surrounded by a solution with a stronger solute concentration than the cell sap, then the vacuole loses water and as a result there is no hydrostatic pressure acting against the cell wall, such cells are said to be flaccid or plasmolysed . Turgid and plasmolysed cells can be seen when pieces of the thin membrane from a red onion are placed in different solutions of different concentrations . While turgor and osmosis play an important role, other factors are also involved. When transverse sections of dicotyledons stems are observed, vascular tissue arranged in vascular bundles can be seen situated near the periphery of the stem.
Vascular tissue is involved with the transport of material.
Phloem is a specialised form of parenchyma, made up of sieve elements and companion cells, whose function is the transport of materials produced during photosynthesis. Fibres within the phloem tissue help in supporting the plant. Figure 4 Vascular bundle Xylem, which does not contain living material, transports water and dissolved mineral salts from the roots and also plays an important role in support. Xylem tissue is made up of tracheary elements, which conduct water and dissolved minerals, together with thick non conducting fibres. The hollow tubes of xylem tissue are usually strengthened with lignin, the woody material we are familiar with in trees and shrubs.