Structures of Seed Plants

Structures of Seed Plants Quick Review What are the two kinds of vascular tissue and what are their jobs? What are the four groups of plants and the example for each? Why do seeds provide a survival advantage? (2 things) Why are flowers & fruits advantageous? What is the structure on all plants that helps them avoid drying out? What lives in the pollen grain? Explain the life cycle of all plants. Plant Systems ** Just like we have body systems to different jobs (circulatory, respiratory, etc.), so do plants 1. Root System - made up of only roots 2. Shoot System - stems and leaves ** The vascular tissues of the two systems are connected so the water/food go through the whole plant Roots - Functions Mostly underground Supply plants with water and dissolved minerals from the soil (move up xylem) Hold plants securely in the soil Store extra food (sugar) made during photosynthesis (moved down the phloem) Roots - Structure Outer layer of cells - Epidermis Center of root holds vascular tissue Water diffuses from epidermis to xylem Tip of root - Root Cap Root cap produces slime to help root push through the soil as it grows longer Roots - 2 Types Taproot (found mostly in dicots) – one main root growing downward with tiny small roots that branch out – get water deep underground (carrot) Fibrous (found mostly in monocots) – several roots spread out from the base of the stem – they’re all about the same size – get water close to the surface (grass) Stems - Function Usually located above ground Connects the roots to leaves and flowers Supports the plants body Leaves get better sunlight Flowers are off the ground to be closer to animals for seed dispersal/pollination Some stems store materials (cactus) Stems - 2 Types Herbaceous Stems – soft, thin and flexible – Ex: beans, wildflowers, clovers Woody Stems – rigid stems made of wood and bark – Ex: trees and shrubs Leaves - Function Make food for the plant (sugar) Absorb Carbon Dioxide (CO2) *Photosynthesis Equation* Water + CO2 + light energy --> sugar +O2 Leaves - Structure Outer surface - covered in a cuticle to prevent water loss Epidermis - single layer of cells beneath the cuticle (light can pass through) Stomata: openings in the epidermis that let CO2 into the leaf Guard Cells: open and close the stomata Palisade Layer - one of the middle layers that has many chloroplasts (for photosynthesis!) Spongy Layer - where xylem & phloem are found Leaf Diagram Gas Exchange in Leaves CO2 enters the plant’s leaves through the stomata Stomata: holes in the leaf’s epidermis; surrounded by guard cells which open and close the stomata Water can also escape through these stomata (BAD!). This loss of water from leaves is called Transpiration. Flowers - Function Adaptations for sexual reproduction Colorful flowers attract animals for pollination Flowers produce nectar, which animals drink and thus pollinate the plant Flowers - Basic Parts 4 Basic Parts: Sepal - modified leaves that make up the outermost ring of flower to protect the bud Petal - broad, flat, thin leaf-like parts of a flower; attract animals to pollinate Stamen - male reproductive structure; made up of a filament and an anther Pistil - female reproductive structure on a flower; made up of the stigma, style and ovary Flower Diagram Pollination & Fertilization Pollination: the transfer of pollen from the male to female structure on a plant Fertilization: when a sperm fuses with an egg inside an ovule Pollination & Fertilization Flower to Fruit to Seed From Seed to Plant Seeds can be dormant (inactive) for long periods of time if the environment is not suitable. Once they are planted in a good environment (water, air, warmth), the seeds germinate (sprout).

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