Anatomy SWBAT discuss the methods of support found in plants; describe the function and structure of xylem and phloem; describe or give a function of cork, fibers, epidermis, and bark; identify annual rings and explain how they can be used to reveal a trees history

Facets of Botany: Story in the Woods – Tree Rings How do annual rings form in trees? –Springwood is produced in spring and early summer from the xylem, when there is a lot of water and sugar to transport, making it lighter in color. Then in late summer and early autumn summer wood is made which has thicker cell walls and appears darker, giving the tree what looks like rings in a cross section.

Facets of Botany: Story in the Woods – Tree Rings What information can annual growth rings give us? –Growth rings can show the relative amount of sun and water and if the tree received damage or was knocked over. What is the difference between heartwood and sapwood? –Heartwood is xylem that no longer carries water and accumulates other materials that make it harder and darker. It protects the tree from parasites. The sapwood still has working xylem and is softer than heartwood.

Anatomy What two characteristics are especially important to the survival of plants? Why? –Cell walls support plants by bearing weight and producing cellulose to help keep cell walls rigid –Plastids are required for photosynthesis Plastid –The organelle in which photosynthesis occurs

Anatomy What two systems support plants? –Cell walls are rigid and support weight –Turgor pressure keeps the cell walls rigid, and upright What is xylem? –They are like straws. They are made up long, hollow cells and carry water from the roots up the stem to the leaves of a plant or tree.

Anatomy What is phloem? –Tissue in plants that carries sugar from the leaves to other parts of the plants. It conducts liquids but carries different fluids than xylem, and its cells are not completely hollow. Vascular bundles –Arrangement of xylem and phloem together in a plant. They are often supported by thick walled cells called fibers

Anatomy Fibers –Long, narrow cells with thick walls. Not hollow tubes, but they taper to points Epidermis –Outermost tissue of leaves, young roots, and young stems. They are made up of flat cells that are effective against water loss. Secretes cuticle

Anatomy Cuticle –Protective waxy layer that covers leaves. Bark –Outside the xylem of a tree Vascular cambium –Makes new xylem and phloem cells. It is located inside the bark

Anatomy Cork –Found in the bark and is made up of dead cells with thick walls. It forms a waterproof coating that keeps harmful organisms out and moisture in. Cork cambium –Living cells inside the cork that divides and produces new cork cells

With a partner With a partner, draw a cross section of a tree and label where you would find the xylem, phloem, fibers, epidermis, bark, vascular cambium, cork, and cork cambium.