Vascular Plants with Seeds

C9L3P2

Plant Tissues

tissuea group of similar cells

working together to perform a particular function

A typical plant has 3 distinct kinds of tissue

• Dermal tissue

• Ground tissue

• Vascular tissue

Dermal TissueProtection

Prevent loss of water

Examples: epidermis, periderm

Ground TissueMetabolismStorageSupport

Examples: parenchyma, collenchyma, schlerenchyma

Vascular TissueTransport water and sugar

Examples: xylem, phloem

Vascular Tissue

The plant’s sap-conducting tissues

Two types: xylem & phloem

Xylem: transports water and dissolved minerals (one kind of sap) upward (long, thick-walled cells)

Phloem: transports food manufactured in the leaves (the other kind of sap) downward

Vascular TissueIn leaves and in non-woody plants, the xylem and phloem are usually arranged in vascular bundles (veins). Vascular bundles are often supported by thick-walled cells called fibers.

Fibrovasular bundles: xylem and phloem surrounded by supporting tissues

Two kinds of xylem cells are tracheids and vessel elements.

All vascular plants have xylem that is composed of tracheids.

Tracheid cells die at maturity, leaving a hollow tube that water can flow through freely.

Xylem

Xylem in flowering plants also includes cells called vessel elements.

The end of vessel elements have larger openings than those found in tracheid cells. Water can pass through easily.

Xylem

Another type of vascular tissue—phloem—carries dissolved sugars throughout a plant.

Phloem is composed of two types of cells—sieve-tube elements and companion cells.

Phloem

Sieve-tube elements are long, thin cells stacked end-to-end to form long tubes.

A companion cell helps control the functions of the sieve-tube element.

Phloem

Vascular Tissue

Vascular Tissue

XylemPhloem

Vascular Tissue

Vascular Tissue

Vascular TissueSunflowerStem

Vascular Tissue