Notes Section 5-1 Characteristics of Seed Plants 1. Use pollen and seeds to reproduce. a. Pollen—contain cells that will later become sperm cells. b. Seed---structure that contains a young plant inside a protective covering. 2. Have vascular tissue. a. Phloem--- Carries food from leaves to other parts of the plant. b. Xylem---Carries water from the roots to other parts of the plant. Seeds: Function of a Seed: 1. Partially developed plant 2. Grows into a new plant if the conditions are favorable Seed Structure: 1. embryo--- young plant that develops from the zygote or fertilized egg 2. stored food---cotyledons (seed leaves) can store food in many seeds 3. seed coat---outer covering that protects it from drying out Seed Dispersal: Promote better chance of survival 1. inside a fruit/eaten by an animal 2. Carried on animals fur 3. wind 4. water 5. mechanically propelled Germination: Occurs when the embryo begins to grow and pushes out of the seed. Roots: Function of a Root: 1. Anchor a plant in the ground 2. Absorb water and minerals from the soil 3. Sometimes store food Types of Root systems: 1. Fibrous root—similar sized roots spread out over wide area in a tangled mass 2. Tap root—has one main root that goes deep into soil and smaller roots branching off the main root Root Structure: 1. Root cap—Protects the root from injury as it grows through the soil. 2. Area of dividing cells—where new growth occurs called the cambium 3. Root hairs—Increase surface area so the root can absorb more water and help to anchor the plant. 4. Vascular tissue—transports food and water through the plant Stems: Function of a Stem: 1. Carries substances between the roots and leaves. 2. Provides support for the plant. 3. Holds up the leaves so they are exposed to the sun. Stem Structure: 1. Herbaceous—contain no wood and are often soft. Ex: tomato plant 2. Woody—hard and rigid Ex: maple tree a. Bark—outer protective layer and inner layer of phloem b. Cambium—divides to make new phloem and xylem c. Xylem—Sapwood: active xylem Heartwood: inactive xylem that provides support Annual rings—summer growth is light colored large cells Late summer/fall growth is dark colored small cells Leaves: Function of a Leaf: 1. Capture the sun’s energy 2. Carry out the food-making process of photosynthesis. Leaf Structure: 1. Cuticle—controls water loss 2. Upper leaf cells—packed cells trap the energy in sunlight 3. Lower leaf cells—widely spaced cells the allow carbon dioxide in for photosynthesis 4. Stomata—tiny pores that let carbon dioxide in and oxygen and water vapor out 5. Vascular tissue—in veins through the leaf 6. Chloroplast—capture the sun’s energy, in the upper and lower leaf cells Transpiration: Process by which water leaves a plant through the stomata in the leaves.