Hello!
According to my Campbell Biology 9th ed.book Pg762 Tracheids and vessel elements-," the water- conducting cells of xylem , have thick walls and are dead at functional maturity".
Sclerenchyma cells-Fibers and sclereids-" have thick, lignified walls that help support mature, non-growing parts of the plant".
I am wondering if the answer is Tracheids and vessel elements or Sclerenchyma cells?
Sorry if I posted this in the wrong place!
Thank You,
Abaddon
Tracheids are elongated cells in the xylem of vascular plants that serve in the transport of water and mineral salts. Tracheids are one of two types of tracheary elements, vessel elements being the other. All tracheary elements develop a thick lignified cell wall, and at maturity the protoplast has broken down and disappeared.
The two major functions that tracheids may fulfill are
- part of the transport system
- structural support
In most cases, the prime function of tracheids is transporting water. They occur in vascular bundles throughout the non-woody parts of the vascular plant and provide water and minerals collected by the roots to leaves and other parts of the plant (stem, flowers, fruits etc).
A good example of structural support is in softwoods where tracheids are the major cell type. Tracheids give softwood its strength.
Because tracheids have a much higher surface to volume ratio compared to vessel elements, they serve to hold water against gravity (by adhesion) when transpiration is not occurring. This is likely one mechanism that helps plants prevent air embolisms.
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