Understanding Stem Anatomy
Describe the functions of a stem. Recognize the external structures of a stem. Analyze the internal structures of a stem. Distinguish between the different types of specialized stems.
What are the functions of a stem? Responsible for the size and shape of a plant Made of different materials Wood Herbaceous or soft
What are the functions of a stem? Support the leaves Move water, minerals, and food throughout the plant Translocation Help produce food through photosynthesis Store food that has been manufactured
What are some of the structures on the outside of a stem? Terminal bud Growing point at the tip of the stem Lateral bud Side bud on the stem Node Where the leaf is attached to the stem Internode The area between leaves Leaf scar Scar where leaf falls off of the stem Bud scale scar Scar left behind from last year’s growth Lenticels small spots on the stem that allow exchange gases with its environment
What are some of the structures on the outside of a stem?
What are some of the structures inside a stem? Two ways interior stem tissue is organized Scattered bundles found in monocots. Rings found in dicots.
What are some of the structures inside a stem? Three important internal tissues Xylem Transports the water and minerals throughout the plant Found closer to the center of the stem Phloem Transports food that is produced in the leaf to the rest of the plant Found toward the outside of the stem Cambium Responsible for the production of new xylem and phloem Causes growth in girth of the stem Found between the xylem and the phloem
How can we use the internal structure of a tree stem? Heartwood Darker wood to the center of the tree Provide strength and no longer function in conducting materials Sapwood Lighter wood circling the heartwood Actively conducts water and dissolved minerals
How can we use the internal structure of a tree stem? The age of a tree can be determined by counting annual growth rings. Rapid growth (spring and early summer) = large cells with thin walls = large in diameter Slow growth (mid-to-late summer) = smaller cells and have thicker walls
What are some different kinds of specialized stems? Bulb Very short flattened stem that has several fleshy leaves attached to it found beneath the soil Example = onion Corm A spherical structure Entire structure is stem Example = gladiolus
What are some different kinds of specialized stems? Rhizome A thick underground stem that lies horizontally Example = Hostas and Mother-in-law’s Tongue Tuber A swollen tip that stores food Example = Irish potatoes Stolon A horizontal stem that lies above the ground that are involved in the spreading of the plant Example = Strawberries
What are some different kinds of specialized stems?